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As an important part of the fields such as renewable energy and electric vehicles, electrochemical energy storage technology faces significant challenges in improving energy density, extending battery life and improving safety. We successfully prepared a composite battery separator of polyvinylidene fluoride-chlorotrifluorinylene (PVDF-CTFE) and fluorinated polyimide (F-PI) -based materials, mixed it with different contents of boehmite nanoparticles, and then modified it by different doses of electron beam irradiation to improve the performance, especially to overcome the problem of maintaining capacity decline in high-speed charging environment. The results showed that the prepared battery separators exhibited outstanding thermal stability, electrochemical properties and ionic conductivity with 12 % boehmite nanoparticles. After 1000 high-speed charge and discharge cycles in current density of 10C, the battery based on the modified separator still maintained a capacity retention rate of 84.4 %, with the initial discharge specific capacity of 111.9 mAhg−1. This means that irradiated separators not only maintain a high energy density in a high-speed charging environment, but also overcome the problem of maintaining capacity decline. Electron beam irradiation further improved the comprehensive performance of the separator. After 1000 and 1500 cycles at the current density of 10C and 15C, the specific discharge capacity of the battery can still retain more than 90 % and 80 % of the initial specific discharge capacity, which provides a longer life in practical applications. [Display omitted] • PVDF-CTFE/F-PI separator containing 12 % boehmite was modified by differnt does of electron beam irradiation for high-rate lithium-ion batteries. • The prepared separators showed outstanding thermal stability, mechanical properties and electrochemical properties. • After 1000 and 1500 cycles at the current density of 10C and 15C, the specific discharge capacity of the battery can still retain more than 90 % and 80 %. [ABSTRACT FROM AUTHOR]

Conventional separators applied in lithium batteries face limitations like low porosity, poor electrolyte wettability, lower cation selectivity, and thermal instability, which impact battery performance and safety characteristics. Besides the challenge in separator design, transition metal ion migration from positive electrodes during cycling greatly accelerates capacity fading because of unrestricted diffusion of transition metal cation across the separator. This study explores an innovative strategy for the separator design by incorporating MXene (spraying MXene solution on both sides of the separator), a two-dimensional material, into electrospun Polyacrylonitrile/Polyetherimide membranes with the function of cation selection. Li+ can be accelerated, and its transference number increases along with the anion limitation in the MXene layer. Ni, Co, and Mn ion dissolution from the positive electrode is inhibited due to the cation selectivity of the MXene layer. Leveraging electrospinning advantages, the resultant membranes exhibit high porosity, excellent liquid absorption, mechanical strength, and superior thermal properties. Benefiting from MXene's layered structure and excellent adsorption ability, the membrane significantly inhibits the dissolution of transition metal ions while enabling smooth lithium deposition due to its cation selectivity. Eventually, the Li||NMC811 batteries deliver outstanding cyclic performance (91.3 % capacity retention after 200 cycles) and robust lithium dendrite suppression (800 h of stable cycling). Moreover, the MXene-modified membrane demonstrates exceptional electrolyte wettability, significantly improving ionic transference number (0.67) and conductivity (1.6 mS/cm). Modification of membrane surfaces with MXene offers insights into addressing transition metal ion migration from the positive electrode material perspective, providing a promising avenue for high-performance LIBs. [Display omitted] • Uniformly sized nanofiber membranes were obtained via electrospinning with uniform MXene composite. • MXene modified membrane exhibits cation selectivity: only Li ion transferred while transition metal ions retained. • The excellent interlayer spacing of MXene restricts lithium deposition in the vertical direction to inhibit dendrite growth. • Li.||NCM811 batteries exhibit a capacity retention rate of 91.3 % with deposition-stripping cycling for 600 h at 2 mA cm−2. [ABSTRACT FROM AUTHOR]

Chemical stability and the trade-off between ion conductivity and dimensional stability are two primary challenges for the development of suitable anion exchange membranes (AEMs). Herein, a series of non-crosslinked poly(norbornene derivatives)-based AEMs containing a bulky steric hindrance hydrophobic arylene substituent were prepared by vinyl addition polymerization (VAP), ring-opening metathesis polymerization (ROMP), and ROMP followed post-hydrogenation, respectively. Compared with ROMP and hydrogenated type membranes, VAP-type membranes, especially the VAP-N-50, exhibited excellent dimensional stability with limited swelling ratio (SR = 27.9 %) while higher water uptake (WU = 213.8 %) at 80 °C, which is attributed to its rigid VAP-type cyclic chain backbone. Microtopography study demonstrated the existence of nanoscale phase separation in VAP-type AEMs and its association with water uptake and swelling behavior. VAP-N-60 showed excellent hydroxide conductivity up to 105.5 mS cm−1 at 80 °C, while exhibited superior alkaline stability that was not found in ROMP-type membrane ROMP-N-50 and the hydrogenated-type membrane H-ROMP-N-50. After being immersed in 2 M NaOH solution at 80 °C for 1200 h, the hydroxide conductivity loss of VAP-N-60 was only 3.0 %. Furthermore, a H 2 /O 2 single cell using VAP-N-50 membrane achieved the highest peak power density of 722 mW cm−2 at 60 °C without back pressure. [Display omitted] • A novel VAP-type poly (norbornene derivatives)-based AEMs were explored. • The performance of the VAP-type AEMs were compared with those of the ROMP-type and theirs hydrogenated AEMs. • The VAP-type AEMs exhibited excellent dimensional stability and alkaline stability. • The VAP-type AEMs exhibited high ionic conductivity and peak power density. [ABSTRACT FROM AUTHOR]

The well-ordered microstructure has been demonstrated to accelerate the proton conduction process through reducing proton conduction resistance. In this research, the proton exchange membranes (PEMs) with sandwich-like microstructure have been constructed based on Kevlar nanofibers and bifunctional nanofibers of chitosan (CS) with polyvinyl alcohol (PVA). The CS/PVA bifunctional nanofibers (CPNF) layer has been prepared with electrospinning process, which is stably adhered to the Kevlar nanofibers layer owing to compatible interfacial property. The fine structure stability without layer separation is achieved even with phosphoric acid (PA) molecules doping in the prepared PA doped composite membranes. The fibrous microstructure accelerats proton conduction through regulating proton conduction pathways. The objective of accelerating proton conduction at subzero temperature has been realized, reflecting in high and stable proton conductivities. For instance, the (Kevlar/CPNF/Kevlar)/PA membrane exhibits proton conductivities of 9.75 × 10−3 S/cm at −30 °C and 8.22 × 10−2 S/cm at 30 °C. Most importantly, the fine proton conductivity stability is identified by the results of the cycle test and long-term test. Specifically, the proton conductivities are respectively 8.62 × 10−3 S/cm at −30 °C and 8.07 × 10−2 S/cm at 30 °C after a five heating/cooling cycle process. The proton conductivities remain 2.97 × 10−2 S/cm at −25 °C and 7.19 × 10−2 S/cm at 30 °C after a 1032 h non-stop test. Additionally, the single proton exchange membrane fuel cell with the (Kevlar/CPNF/Kevlar)/PA membrane exhibits the peak power densities of 279.5 mW/cm2 at 100 °C and 352.7 mW/cm2 at 130 °C. [Display omitted] • Bifunctional nanofibers were used to construct proton exchange membranes. • Accelerating proton conduction at subzero temperature was achieved. • Conductivity reached 2.97 × 10−2 S/cm at −30 °C after a 1015 h non-stop test. [ABSTRACT FROM AUTHOR]

It is an attractive way to produce hydrogen for energy storage via water electrolysis by using unstable energy sources changing with time and geographical location. However, water electrolysis still suffers some problems from such as low operating current density. We herein propose a novel bipolar membrane crosslinked with bipyridine covalent triazine frameworks (bipCTF) based on sulfonated poly (4,4′-diphenylether-5,5′-bibenzimidazole) (SOPBI). The prepared bipCTF-SOPBI membranes exhibit the highest ionic conductivity of 143 mS cm−1 to protons, and of 48.0 mS cm−1 to hydroxide ions at 80 °C after doping with H 2 SO 4 /NaOH, respectively. Using the proposed membrane as the diaphragm for the acid-alkaline amphoteric water electrolysis, a current density of 1.29 A cm−2 is achieved at a voltage of 2.5 V at 80 °C. The electrolytic cell system could work stably at a current density of 100 mA cm−2 at 20 °C for 90 h. [Display omitted] • Crosslinking of the sulfonated polymer SOPBI with covalent triazine framework (bipCTF). • Enriched acid-base pairs endow the membrane bipCTF-SOPBI with superior ionic conductivity. • An amphoteric water electrolytic cell with bipCTF-SOPBIdiaphragm exhibits 1.29 A cm−2 of current density at 2.5 V & 80 °C. • The assembled cell system could work stably for 90 h at a current density of 100 mA cm−2. [ABSTRACT FROM AUTHOR]

Recently, sodium-ion batteries have received great attention primarily due to the scarcity of lithium resources and fluctuations in lithium prices, but sodium-ion batteries have relatively low energy densities. One solution to the low energy density is to employ sodium metal anode, and the risks associated with using metallic sodium could be mitigated by constructing sodium-metal batteries (SMBs) with polymer electrolytes. In this paper, we would like to report a novel gel polymer membrane composed of a cellulose polymer, which not only has a wide electrochemical window, but also has excellent mechanical strength and thermal stability. Moreover, the prepared membrane exhibits high ionic conductivity, thus it can be used as separator and/or electrolyte for ionic batteries. The sodium-metal battery constructed with the prepared gel cellulose electrolyte has been further evaluated by cycling at 0.1C and 60 °C. The solid electrolyte interphase (SEI) layer formed on the surface of the sodium metal anode has been carefully examined using various characterization techniques. The results verify that the ionic-liquids based gel polymer electrolyte (IGPE) is thermally and electrochemically stable, and suitable for high-voltage SMBs. [Display omitted] • Preparation of ionic gel polymer electrolyte (IGPE) from natural abundant biodegradable cellulose derivative. • IGPE membrane: transparent, flexible, thermal/electrochemical stable and ionic conductive. • High electrochemical window of the IGPE membrane (5.46V). • Ionic conductivity of IGPE membrane suitable for separators/electrolytes. • Excellent battery performance of assembled sodium metal battery with IGPE membrane. [ABSTRACT FROM AUTHOR]

Polycyclic norbornene derivatives, dicyclopentadiene (DCPD) and tricyclopentadiene (TCPD), have rigid structures with ease of accessibility and high chemical reactivity. After vinylic-addition polymerization, the resultant polynorbornenes (PNBs) possess high thermal stability, excellent mechanical integrity, and chemical inertness due to the retention of the rigid polycyclic norbornene motifs along the polymer backbones. Herein, we first report polycyclic PNBs composing DCPD or TCPD and an alkyl-bromide-substituted norbornene as comonomers to prepare high performance anion-exchange membranes (AEMs). The two double bonds in DCPD/TCPD can be used for vinylic-addition polymerization and thiol-ene click cross-linking reactions, respectively. By comparing with previously reported cross-linked PNB AEMs without polycyclic structures, it is unambiguously confirmed that the involvement of DCPD/TCPD significantly improved the mechanical strength (the stress-at-break of 34 MPa vs 28 MPa), the hydroxide conductivity (212 mS cm−1 vs 199 mS cm−1 at 90 °C), and the alkaline stability (93 % vs 81 % conductivity remaining after treating in 1 M KOH at 80 °C for 1200 h). The successful application of the AEMs with excellent durability for over 500 h prove that the involvement of polycyclic structures is a convenient strategy to enhance the performance of aromatic-free AEMs. [Display omitted] • Vinylic addition polynorbornene backbones composed of polycyclic structures and pendant alkenes. • Pendant alkenes were used for efficient dithiol cross-linking. • Polycyclic structures improved the mechanical strength, ionic conductivity, and chemical stability. • Ultrahigh hydroxide conductivities and excellent alkaline stability were achieved. [ABSTRACT FROM AUTHOR]

Carbazole and its derivatives have recently shown considerable potential for application in anion exchange membranes (AEMs), yet only a few studies have been reported so far. Herein, a carbazole derivative with multiple phenyls was synthesized, which was copolymerized into the polymer backbone, subsequently by densely piperidinium-functionalized, yielding a series of copolymers named PIP-PAESK-Cz- x as AEMs. The prepared membranes indicated well-defined microscopic morphology due to the drastic polarity contrast between the hydrophilic units and hydrophobic polymer backbone. Furthermore, compared with another analogous AEM, the presence of rigid carbazole significantly improved the water adsorption and alleviated the aggressiveness of OH− for PIP-PAESK-Cz- x. Consequently, the PIP-PAESK-Cz-25 membrane demonstrated decent hydroxide conductivity of 61.5 mS cm−1 at 80 °C, and stable performance upon treatment with harsh alkaline environments at 30 °C or 60 °C. In addition, a maximum power density of 407.8 mW cm−2 in the H 2 /O 2 fuel cell was also achieved. This work presented a novel strategy to exploit the carbazole, which is expected to provide additional ideas for more carbazole-based AEMs in the future. [Display omitted] • A novel strategy to exploit the carbazole for AEMs is investigated. • Densely piperidinium-modified carbazole derivatives are formed in the main chain. • Well-defined microscopic morphology promotes the hydroxide conductivity of AEMs. • Carbazole alleviates the aggressiveness of OH− toward adjacent cationic groups. [ABSTRACT FROM AUTHOR]

Anion-exchange membranes (AEMs) have gained widespread attention as another rising star among the core components of fuel cells. However, the disadvantages of low electrical conductivity and poor chemical stability greatly limit its development. Here, indeno carbazole monomers were introduced into the ether-free backbone and hydrophilic alkoxy side chains were suspended from the side chains to prepare a series of poly (indeno carbazolyl-aryl) piperidine membranes. Indeno carbazole is a nitrogen-containing heterocyclic compound with a large conjugation system, which provides a large volume of space to avoid close stacking of polymer molecules, and provides a place for the aggregation of water molecules without excessive swelling. The hydrophilic alkoxy side chain, as a hydrophilic group, absorbs a large amount of water and at the same time the oxygen atom will form cation-dipole interactions with the cation to induce cation aggregation. In addition, the polarity difference between the hydrophobic main chain and the hydrophilic side chain creates an obvious microphase separation structure, and the high-water absorption generated by the two can also reduce the attack of alkali on the cations, thus further improving the chemical stability of the membrane. At 80 °C, the relatively low IEC qPTP-IC-O-9% membrane instead achieved the highest ionic conductivity (137.5 mS cm−1) and peak power density (406 mW cm−2), and the conductivity retention was at 97.9% after 1300 h of immersion in 3 M NaOH at 80 °C. In addition, the qPTP-IC-O-9% membrane maintained 71.7% of the initial voltage after 30 h durability test at 80 °C, 0.05 A cm−2. To sum up, the qPTP-IC-O-9% membrane has a very bright future in promoting the further rapid development of hydroxide fuel cells. [Display omitted] • Introduction of bulky monomers to increase free volume and cation clusters. • Grafting alkoxy chains build polar differences and cation-dipole interactions. • Main and side chains synergistically optimize conductivity and alkali stability. [ABSTRACT FROM AUTHOR]

Anion exchange membranes (AEMs) are key core materials in water electrolysis, requiring excellent conductivity and chemical durability. In this study, the suspended dense alkyl ether linkages and 1,2,4,5-tetramethylimidazolium ions with high stability are introduced into the polymer structure (PAES-FTMI-x, x = 0.15–0.30) for AEMs. The obtained AEMs with ion exchange capacity of 1.22–1.74 mmol g−1 exhibit high conductivity and dimensional stability. Their hydroxide ionic conductivity and swelling ratio are in the range of 76.28–113.17 mS cm−1 and 9.7%–17.0 % at 80 °C, respectively. The conductivity retention for the representative sample PAES-FTMI-0.25 achieves 90.6 % after soaked in 2 mol L−1 NaOH and 80 °C for 480 h. The assemble water electrolyzer based on PAES-FTMI-0.25 shows 734.97 mA cm−2 of current density at 2 mol L−1 NaOH and 2.0 V of voltage when the temperature is RT. It also has good durable stability at a current density of 500 mA cm−2 for 480 h with only 0.02 V decrease of voltage. This work would provide an effective strategy for the collaborative design and modification of AEMs for alkaline electrolyzed water. [Display omitted] • Suspended side-chain-type 1,2,4,5-tetramethylimidazolium AEMs were prepared. • Dense flexible alkyl ether linkage improved ionic conductivity of membranes. • The multi-substituted imidazolium cations enhanced alkaline stability of AEMs. • Excellent dimensional stability as well as good water electrolyzer properties. [ABSTRACT FROM AUTHOR]

Poly (ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) are restricted in commercial applications due to the low ionic conductivity at ambient temperature and fragile mechanical properties. Polyurethanes (PUs) are unique materials coupled with superior rigidity and flexibility. Herein, we designed a novel polyurethane polymer of intrinsic microporosity (PPU), which was incorporated with PEO-based polymer electrolyte to prepare composite polymer electrolyte (CPE). The physicochemical and electrochemical properties of CPE membranes were explored. The high ionic conductivity (1.82 × 10−3 S cm−1 at 50 °C) and superior interfacial stability with the lithium anode was obtained. Furthermore, the rate performances and the cycling properties of CPE in LiFePO 4 (LFP) batteries were extensively studied. The CPE-15% PPU film showed the excellent electrochemical stability of 84.3% capacity retention after 890 cycles at 0.5 C and 82.4% capacity retention after 500 cycles at 1.0 C at 50 °C. Especially, the CPE matched with high-voltage LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) cathode delivered long-term stable cycling performances. The novel polymer electrolyte acquired could open up a new horizon to achieve high stable lithium metal batteries. [Display omitted] • A novel polyurethane polymer of intrinsic microporosity (PPU) is designed. • The PEO-based composite polymer electrolyte (CPE) mixed with PPU is fabricated. • The stable electrode-electrolyte interface is achieved. • The CPE owns superior cycling performance under high-voltage atmosphere. • The Li metal battery equipped with CPE exhibits a long-term cycling stability. [ABSTRACT FROM AUTHOR]

Concerted motions of ions arising due to ion aggregation and counterion condensation are often neglected when interpreting salt transport in ion exchange membranes. In this study, we apply the Onsager transport framework to atomistic molecular dynamics simulations to study the impact of such physics on salt transport properties in a model cation exchange membrane as a function of membrane water volume fraction, sulfonation fraction, and cation identity. Cations and anions, distinct cations, and distinct anions tend to move in the same direction due to the formation and resulting motion of ionic aggregates. Such motions, in general, increase the salt diffusion coefficient and decrease the conductivity relative to "ideal" values which envision the ions to move independently of each other. In contrast, condensation-induced slowdown inhibits the motion of ionic aggregates since the condensed counterions serve as a connection between aggregates and the immobile polymer matrix. Such effects decrease deviations of salt transport properties from the ideal assumption. We demonstrate that experimentally extracted cation/anion self-diffusion coefficients can exhibit significant errors if correlated motions arising from ion aggregation are neglected. • Ionic aggregate motion significantly effects salt transport properties. • Counterion condensation inhibits aggregate motions by slowing down associated ions. • The Onsager framework can probe the impact of aggregate motions on salt transport. • Ion aggregation should be accounted for in investigations of salt transport. [Display omitted] [ABSTRACT FROM AUTHOR]

Porous separators are essential for alkaline electrochemical energy technologies, such as alkaline water electrolyzers (AWEs). These separators are promising alternatives to dense membranes because they offer the potential for low cost and high ionic conductivity. However, two significant challenges in developing efficient and durable alkaline energy systems are the suppression of hydroxide ions-induced degradation and the reduction of gas permeation in porous separators. Compared to hydrophobic polysulfone (PSF), KOH-doped poly (oxindole biphenylene) (POBP) is a highly stable ion-solvating polymer that can conduct both potassium and hydroxide ions. Building upon this, a series of porous separators based on POBP polymer with different zirconia loads were designed using NIPS to investigate the chemical stability and water electrolysis performance where the Z60 separator exhibits remarkable characteristics, including low area resistance (0.227 Ω cm2), high bubble point pressure (0.813 MPa), low H 2 permeability (0.5 L min−1·cm−2) and exceptional 5040 h of ex-situ durability in 6 M KOH at 80 °C. Furthermore, the Z60 diaphragm showed a higher breaking time and lower weight loss after 261 h at 80 °C in the Fenton reagent, with the remaining mass being Z60 was 38 %. Notably, the Z60 diaphragm, when equipped with Ni–Al catalysts, achieved a current density of 0.5 A/cm2 at 1.7 V, which surpasses that of Zirfon (0.5 A/cm2 at 1.8 V). More importantly, when using Ni foam catalysts, the Z60 diaphragm demonstrated stable operation under 0.125 and 0.5 A/cm2 current densities at 80 °C for more than 900 h and 1200 h, significantly improving the durability of the porous separators. The results of this study showed that the blending of POBP can lead to the development of highly chemically stable porous diaphragms, thereby opening up a new avenue for advanced AWEs. This work developed POBP/ZrO 2 porous composite separators exhibited superior alkaline water electrolysis performance and excellent durability. [Display omitted] • The chemical stability of POBP/ZrO 2 porous composite separators was significantly improved. • The separator with thin skin layer showed low area resistance, high bubble point pressure and low H 2 permeability. • The Z60 diaphragm exhibited superior water electrolysis performance and excellent durability. [ABSTRACT FROM AUTHOR]

Fabricating the cross-linked network is an efficient strategy for improving the mechanical and electrochemical performances of polymer electrolytes (PEs). However, present methods used for the preparation of the cross-linked PEs is difficult to remove the residual catalyst and avoid the side reactions, and the ion conduction in solid PEs is often confined. Herein, we report that the deep eutectic solvent (DES) via the Li–N interaction of 1,2-dimethylimidazole (DMIm) and bis(trifluoromethane)sulfonimide lithium (LiTFSI) displays synergistic effects in inducing the ring-opening polymerization (ROP) of trimethylene carbonate (TMC) and thiol-Michael addition reaction, permitting in situ preparation of PEs with a cross-linked structure. Moreover, DMIm-based DES not only endows PEs with the flame-retardant property but also promotes the conduction of Li ions (Li+) in PEs, leading to a good ionic conductivity at 60 °C (1.8 × 10−4 S cm−1) and Li+ transference number (0.41). Notably, no obvious short-circuit at 0.1 mA cm−2 appears during the deposition process of lithium symmetric batteries assembled with PEs after 1200 h. [Display omitted] • Polymer electrolytes formed via DES-induced in situ polymerizations. • Desirable interfacial compatibility for lithium metal batteries. • Li.| |LiFePO 4 cell with an excellent cycling stability. [ABSTRACT FROM AUTHOR]

As the core material of alkaline fuel cells, anion exchange membranes (AEMs) are one of the keys to determining the comprehensive performance of fuel cells. However, drawbacks, such as impoverished alkali stability, insufficient mechanical properties, and particularly low ionic conductivity, affect their application in fuel cells. Herein, a series of AEMs based on a new arylfluoroketone monomer [1-bromo-3- (trifluoroacetyl phenyl)-propane, TFAP-Br] was prepared using a backbone modification strategy. This study aims to investigate the effects of introducing TFAP-Br for copolymerization on the microphase separation, ionic conductivity, and mechanical properties of AEMs. Due to the presence of long side chains of alkylfluoroketone and arylfluoroketone, the AEMs exhibit a prominent microphase separation state, and the OH− conductivity can reach 156 mS cm−1 at 80 °C (IEC = 2.73 meq g−1). QBPNP-10 shows excellent mechanical properties with the elongation at break up to 91% in wet state and good alkali resistance with 95.2% OH− conductivity retention in a NaOH solution (2 mol L−1, 80 °C, 1560 h). Moreover, the peak power density (PPD) of a single cell assembled with QBPNP-10 can reach 852 mW cm−2 (80 °C), and the membrane has good in-situ durability. [Display omitted] • The QBPNP-10 AEM shows excellent mechanical properties with elongation at break up to 91% in wet state. • The QBPNP-10 AEM exhibits a highest ionic conductivity of 156 mS cm−1 at 80 °C. • The peak power density of QBPNP-10 in a H 2 /O 2 single cell is 852 mW cm−2. [ABSTRACT FROM AUTHOR]

Anion-exchange membrane fuel cells (AEMFCs) have garnered substantial attention over the past two decades due to their numerous advantages, positioning them as promising alternatives to proton exchange membrane fuel cells (PEMFCs). However, their rapid development faces notable challenges, including the limited high-temperature and alkaline stability of anion-exchange membranes due to the incorporation of cationic functional groups, as well as intricate preparation processes. In this study, we propose a high-temperature inorganic anion exchange membrane based on layered double hydroxide doped with K 2 CO 3 prepared by a simple process. This innovative approach optimizes the ionic transport pathway within the LDHs inorganic membrane and enhances water retention performance at elevated temperatures. The maximum cross-plane ionic conductivity of the membrane can reach up to 10−2 S cm−1. Remarkably, the peak power density attains an impressive level of 215.2 mW cm−2 at 110 °C and 200 kPa during the fuel cell testing. [Display omitted] • Inorganic anion exchange membranes (AEMs) are applied for fuel cells. • The hygroscopicity of K 2 CO 3 boosts the hydration and ionic conductivity of AEMs. • Working temperature goes up to 110 °C. • The peak power density of inorganic AEMFCs reaches 215 mW cm−2 at 110 °C. [ABSTRACT FROM AUTHOR]

The stability and the performance of the bipolar membrane (BPM) are the critical issues to be resolved. The layer thickness plays an important role in improving the performance of bipolar membrane. Here, an efficient transparent asymmetric bipolar membrane has been fabricated by a layer-by-layer solution casting technique comprising cation and anion exchange layers. The thickness of the anion exchange layer was reduced to improve the performance in term of product purity and recovery by minimizing the co-ion leakage. The interface of BPM acts as a catalytic junction for dissociating the water into H+ and OH− ions. A clear membrane interface was confirmed by the scanning electron microscopy (SEM). All three BPMs show the adequate physicochemical and electrochemical properties in term of ionic conductivity and water uptake. Effect of applied potential was studied on the membrane performance through BMED for the dissociation of NaCl. We also performed the bipolar membrane electrodialysis (BMED) for the hydrolysis of different organic and inorganic salts into corresponding acid and alkali. Among the bipolar membranes, BPM with 40 % less AEL thickness (BPM-60 membrane) shows the better performance. BPM-60 shows the highest water splitting rate and alkali recovery of 0.491 g h−1 and 95.5 %, respectively with lowest energy consumption of 1.11 kW h kg−1 and high current efficiency of 90.32 %. Conversion of NaCl in to NaOH and HCl gives the highest product recovery as compared to other salts, due to higher dissociation of NaCl. BPM-60 with higher water splitting rate, lower energy consumption and higher current efficiency for conversion of salt into corresponding acid and alkali made asymmetric bipolar membrane as industrially applicable with high performance. [Display omitted] • Layer-by-layer solution casting provides the strong adhesion among the layers of BPMs. • Reduction in AEM improved the water splitting efficiency and stability. • 95.5 % product recovery was obtained using BPM-60 membrane by BMED. • BPM-60 shows better current efficiency and energy consumption as compared to reported membranes. • No delamination after multiple use of the membranes. [ABSTRACT FROM AUTHOR]

Anion exchange membrane (AEM) with high ionic conductivity and stable dimension is urgently needed to improve cost-effective anion exchange membrane fuel cells (AEMFC). In this study, a dibenzofuran-containing poly(terphenyl furan piperidinium) (QPTFP) membrane is successfully synthesized in large quantities with a yield exceeding 500 g for the purpose of large-scale AEM production. The introduction of non-rotatable dibenzofurans results in an acceptable swelling ratio of 25 % and high ionic conductivity of 155 mS cm−1 at 80 °C. It also exhibits a favorable tensile strength of 52.6 MPa and excellent alkaline stability of 2200 h at 80 °C in 1 M KOH. Furthermore, the AEMFC employing QPTFP membrane achieves remarkable peak power densities at 80 °C for H 2 –O 2 (2 W cm−2) and H 2 -Air (1.2 W cm−2), and demonstrates excellent stability of over 90 h at 70 °C and a current density of 0.2 A cm−2. [Display omitted] • Poly(aryl furan piperidinium)s are prepared for the continuous production of anion exchange membranes. • The membrane shows the highest conductivity of 155 mS cm−1 and excellent stability of >2200 h. • The fuel cell exhibits the highest peak power density of 2 W cm−2 (H 2 –O 2) and 1.3 W cm−2 (H 2 -Air). • The QPTFP-25 AEM is stabilized of fuel cell operation for 90 h at 70 °C. [ABSTRACT FROM AUTHOR]

Single-ion polymer electrolytes (SIPEs) with high Li-ion transference number (t Li +≈1) are promising candidates for inhibiting the growth of lithium dendrites in lithium metal batteries (LMBs). However, it remains challenging to develop SIPEs applicable to high-performance LMBs due to their relatively low ionic conductivity and poor mechanical strength. Herein, an aromatic single-ion conductor (LiPSBI) with high Li-ion concentration is elaborately designed, yielding porous and mechanically robust SIPE membranes (NSIPM) when mixed with aliphatic poly (vinylidene fluoride-hexafluoropropylene) P(VDF-HFP) binder via "structural self-assembly" method. As expected, the as-prepared NSIPM porous membranes can simultaneously exhibit a high porosity of 41.4%, a considerable organic solvent uptake of 181.0%, and excellent mechanical strength of 20.5 MPa. Notably, the LiPSBI-based gel NSIPM demonstrates an ionic conductivity of 8.15 × 10−5 S cm−1 at 25 °C, which is almost twice that of the single-ion electrolyte with low Li-ion concentration (4.74 × 10−5 S cm−1). Consequently, the Li||LiFePO 4 cells using the gel NSIPM display remarkable cycling durability for several hundred cycles while delivering high discharge specific capacities of 148.4 mA h g−1 and 122.9 mA h g−1 at 0.2C and 1 C, respectively. In addition, the Li/Li symmetric cells assembling the gel NSIPM can effectively alleviate concentration polarization and inhibit the lithium dendrites growth, which is responsible for an exceptionally steady striping/plating process with a low overpotential over 1300 h at 2.5 mA cm−1 at 25 °C. This work provides a new strategy to prepare high-performance SIPEs by increasing the concentration of charge carriers. [Display omitted] • A new single-ion conductor containing high Li-ion concentration is well-designed. • The SIPE-based porous membranes are prepared via structural self-assembly method. • Ionic conductivity and mechanical strength of the gel SIPEs are highly improved. • Li.||LiFePO 4 cells with the gel SIPEs run stably at 1 C for 1000 cycles at 25 °C [ABSTRACT FROM AUTHOR]

Garnet-type oxide Li 7 La 3 Zr 2 O 12 (LLZO) has attracted considerable attention as promising solid-state electrolyte (SSE) owing to the exceptional bulk ion conduction. However, the Li+ transfer capacity of most LLZO-based solid electrolytes remains inadequate, primarily due to the presence of extensive grain boundaries and excessive thickness. Herein, we report the fabrication of a LLZO-based lamellar composite inorganic solid electrolyte (LLZO/LIC LISE) by in-situ sintering Li 3 InCl 6 (LIC) in LLZO lamellar framework. LIC can act as an effective Li+-conductive grain boundary modifier within the electrolyte, leading to a remarkable reduction in grain boundary resistance of LLZO/LIC LISE (<9.2 Ω cm2), which is much lower than that of LLZO lamellar framework (827.2 Ω cm2). Together with the reduced internal grain boundary of LLZO nanosheet, a high ionic conductivity of 3.22 × 10−4 S cm−1 at 25 °C is obtained for LLZO/LIC LISE. In addition, combining with the thin thickness of 29 μm, LLZO/LIC LISE obtains high ionic conductance of 223 mS and exceptional energy density of 246 Wh kg−1, surpassing most developed SSEs. As a result, the cell assembled with LLZO/LIC LISE achieves superior cycling performance of 144.2 mAh g−1 after 200 cycles at 0.5C with a capacity decay of only 0.055% per cycle. This study may present a facile approach to effectively eliminate the grain boundary resistance of inorganic solid electrolytes toward high-performance all-solid-state lithium batteries. [Display omitted] • A 29 μm-thick LLZO/LIC lamellar composite solid electrolyte is fabricated. • The presence of LIC imparts ultralow grain boundary resistance (<9.2 Ω cm2). • The interfacial interaction between LLZO and LIC improves electrolyte stability. • The thin thickness affords high ionic conductance and energy density. • Superior performance with capacity of 144.2 mA h g−1 after 200 cycles is attained. [ABSTRACT FROM AUTHOR]

Anion exchange membranes (AEMs) based on non-aryl ether–type poly(aryl piperidinium) have recently drawn significant attention because of their excellent ion exchange capacity (IEC), chemical stability, and ionic conductivity. However, the reactivity of poly(aryl piperidinium) varies significantly depending on the type of monomer used and is also accompanied by very rapid polymerization. These limitations have hindered the development of an AEM with controllable morphology. In the present study, AEMs with the desired morphology were obtained using hydrophilic and hydrophobic monomers; indeed, a well-controlled morphology was achieved even though they were random copolymers. Specifically, hydrophilic dibenzofuran and hydrophobic p -terphenyl were used as raw materials to develop the novel AEM material p(BF-TP)-Pip-x, i.e., a poly(dibenzofuran- p -terphenyl-piperidinium)-based copolymer. The dibenzofuran content relative to p -terphenyl was 5%, 10%, and 30%, resulting in three types of p(BF-TP)-Pip-x-based membranes. Their properties were compared with a poly(p -terphenyl-piperidinium)(pTP-Pip)-based AEM, a homopolymer composed solely of p -terphenyl. p(BF-TP)-Pip-10, a membrane with a dibenzofuran content of 10%, exhibited excellent mechanical properties with a tensile strength of 42 MPa and an elongation of break of 9.7%, along with high ionic conductivity at 144 mS cm−1 at 80 °C, owing to its well-developed, phase-separated morphology. Furthermore, its conductivity retention was 93% after treatment in a 2 M KOH solution at 80 °C for 960 h. For a given IEC, excellent alkaline stability was achieved compared to existing poly(aryl piperidinium)-based AEMs. p(BF-TP)-Pip-10 also exhibited excellent thermal and oxidative stability. In AEM water electrolysis tests, the membrane showed a very high current density of 1309 mA cm−2 at 1.8 V, a 120% improvement over pTP-Pip. [Display omitted] • Poly(dibenzofuran- p -terphenyl piperidinium)s were prepared as new materials for anion exchange membranes. • Hydrophilic-phobic random type copolymer has been prepared. • Effect of phase separation was investigated. • Good phase separation helped to enhance ion conductivity, alkaline stability and cell performance. [ABSTRACT FROM AUTHOR]

The thermal safety of lithium-ion batteries (LIBs) is a major obstacle to expanding LIBs applications. High-safety separators with a thermal shutdown feature are considered the most promising and appealing thermal protection strategy for LIBs to avoid thermal runaway. Herein, a high-safety poly (ethylene-co-vinyl acetate)/poly (ether ether ketone)/poly (ethylene-co-vinyl acetate) (EVA/PEEK/EVA) composite separator is fabricated by dip-coating and thermally induced phase separation. Once the operating temperature exceeds 80 °C inadvertently (the thermal runaway onset temperature), the EVA layers of the EVA/PEEK/EVA separator are converted into barrier membranes to cut off ion transport and prevent battery reactions. Meanwhile, the PEEK substrate remains dimensionally stable even at temperatures up to 240 °C to avoid the dangers associated with thermal inertia after shutdown. Moreover, compared to the polyolefin separator (commercially available), the EVA/PEEK/EVA separator shows an increase of 42% and 77.1% in ionic conductivity and discharge capacity at the rate of 4C, respectively. Therefore, the EVA/PEEK/EVA separator can secure the LIBs without sacrificing electrochemical performance, and further expand the application of LIBs. [Display omitted] • Once the temperature exceeds 80 °C, the separator will achieve thermal shutdown. • The separator can remain dimensionally stable even at temperatures up to 240 °C. • The ionic conductivity of the separator is 42% higher than the commercial separator. [ABSTRACT FROM AUTHOR]

Anion exchange membranes (AEMs) are the core component of anion exchange membrane fuel cells (AEMFCs), among which poly(aryl piperidinium) (PAP) based AEMs have been studied. Herein, we report some scalable di-piperidinium cationic crosslinkers to enhance the mechanical properties, ionic conductivity and alkaline stability of PAP-based AEMs. The results show that the morphology of AEMs can be affected by adjusting the length of crosslinker. PTP-DPC/C6-50% shows a high OH− conductivity (80 °C, 131.2 mS cm−1) due to its microphase separation. It also has excellent elongation at break (20.8%) and tensile strength (36.5 MPa). The peak power density of the PTP-DPC/C6-50% based cell can reach 616.2 mW cm−2 under H 2 –O 2 conditions. The crosslinked network formed by long alkyl spacer chains is helpful to improve the alkaline stability of the AEM. After alkaline stability test, the conductivity of the PTP-DPC/C10-50% membrane maintained at 92.2%. [Display omitted] • Di-piperidine crosslinkers of different lengths are used in crosslinked membranes. • PTP-DPC/C6-50% has an obvious microphase separation morphology. • High conductivity and excellent alkaline stability can be obtained. • The highest power density is 616.2 mW cm−2 in a H 2 –O 2 single cell. [ABSTRACT FROM AUTHOR]

Quaternary ammonium-functionalized anion exchange membranes (AEMs) have important potential application value in water electrolysis. In order to further improve the ionic conductivity and stability of AEMs, a series of crosslinked AEMs based on poly (aryl ether sulfone)s (Co-PAES-QA-x-m, "x" represents the functionalized polymer segment, "m" represents the crosslinking ratio) are prepared by introducing dense quaternary ammonium cations on the side chains via Menshutkin reaction. Their polymer structures are characterized by hydrogen nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy FT-IR, and the microscopic phase separation structure of the obtained membranes is observed by atomic force microscope AFM. The ion exchange capacity (IEC) of Co-PAES-QA-x-m (x = 25%, m = 40%–100%) is between 2.03–2.48 mmol g−1, and their water uptake (WU), swelling ratio (SR) and ionic conductivity are in the range of 26.9–56.7%, 6.3–12.9% and 53.43–119.43 mS cm−1 at 80 °C, respectively. The test of chemical stability show that the ionic conductivity retention ratio of these AEMs reaches 84.7% after soaking in 2 mol L−1 NaOH solution for 480 h at 80 °C. The water electrolyzer assembled with representative Co-PAES-QA-25-60 reaches 1646.7 mA cm−2 in 2 mol L−1 NaOH solution at 2.0 V and 80 °C, and the durability test shows that its voltage only rises by 5% after 480 h at the current density of 500 mA cm−2. This work is expected to provide an effective modification method for high-performance AEMs which are used in water electrolyzer. [Display omitted] • Crosslinked AEMs with dense cations on the side chains were designed. • The crosslinked structure forms ionic network and improves the alkaline stability. • Remarkable dimensional stability and superior current density are achieved. [ABSTRACT FROM AUTHOR]

The emergence of alkaline polyelectrolytes (APEs) with high stability and high ionic conductivity has greatly improved the power density of alkaline polyelectrolyte fuel cells (APEFCs), now the cell stability has become an urgent problem to be addressed. The uneven distribution of humidity and hydration state inside large-scale electrodes will cause the membrane to swell and shrink repeatedly, resulting in the membrane rupture and/or the peeling off of catalyst layers, which is a fatal problem affecting the stability of APEFCs. In the present work, we report a new APE, self-crosslinked quaternary ammonia poly (N-methyl-piperidine-terphenyl and 7-bromo-tri-fluoro-heptanone), denoted as x QAPTF. The crosslinking network inside the membrane can be formed without introducing additional crosslinking agents, and can effectively limit the membrane swelling degree in water (only 4% at 80oC). More importantly, the x QAPTF membranes exhibit excellent mechanical strength and flexibility even after multiple all-wet-all-dry cycles. Under the dry-wet alternating condition (RH repeatedly switched between 100% and 50%), the APEFC using x QAPTF membrane run stably, with the cell voltage switching accordingly and steadily. Such a unique quality of APE membranes has so far not been reported in the literature, which strongly enhances the practicality of APEs, as well as the APEFC and relevant technologies. [Display omitted] •Self-crosslinked alkaline polyelectrolyte membrane. •High in mechanical strength and low in swelling degree. •Exceptionally stable under dry-wet alternating conditions. •An important step towards practical application of APEFC. [ABSTRACT FROM AUTHOR]

In this study the effect of CO 2 , HCO 3 ‾ and CO 3 2‾ on the ionic conductivity and water uptake properties of anion exchange membranes (AEMs) was investigated in order to better understand the detrimental effect of ambient air feed on the performance of AEM fuel cells. Three types of AEMs were examined, including Poly(hexamethyl- p -terphenyl benzimidazolium) (HMT-PMBI), Fumatech® FAA-3, and poly(phenylene oxide) functionalized with imidazole (PPO-Im). The effect of temperature and humidity on AEM properties in their different anion forms was studied, including both steady state and dynamic measurements. In addition, the response to changes in CO 2 concentration and to application of ex-situ electric current was examined. Results showed that an increase in humidity leads to an increase in water content and an increase in conductivity of the AEMs, regardless the anion type. It was found that both temperature and relative humidity improve conductivity in carbonated forms, however relative humidity has the most significant impact. The carbonation process in 400 ppm CO 2 is slightly quicker in AEMs with low conductivity, lasting ca. 40 min; however it was shown that a reverse process can be achieved by applying an electric current through the AEMs. An increase by 2–10 fold in conductivity is obtained using this method, which is analogous to the changes observed during operation of the fuel cell. This work provides important data that needs to be taken into account in future work in order to ultimately mitigate the carbonation effects and improve the performance of AEM fuel cells running with ambient air. Image 1 • The effects of HCO 3 ⁻ and CO 3 2⁻ anions on AEM properties is reported. • (Bi)Carbonate anions lower AEM anion conductivity by 6–10 times. • Self-purging by applying electric current restores high anion conductivity in AEMs. • For this first time the transient behavior of AEMs under CO 2 -environment is studied. [ABSTRACT FROM AUTHOR]

Ionic conductivity and water transport through alkaline Anion Exchange Membranes (AEM) are key properties for application in Alkaline Membrane Fuel Cells (AMFC), Redox-Flow-Cells, or Alkaline Membrane Electrolysis. AEMs consist of a polymer domain with cationic side groups and a pervading water domain through which anions are conducted. In this study, Quasielastic Neutron Scattering (QENS) is employed to study water rotational and diffusive dynamics in the hydroxide form of a model AEM (Fumatech FAA-3) at water contents relevant for application. Two distinct diffusion time- and length-scales are accessed: "Localized" diffusion at the lower Ångstrom/tens of picosecond scale and "extended" diffusion at the higher Ångstrom/hundreds of picosecond scale. The localized diffusion length scale is smaller than the membrane's water domain thickness and its diffusion coefficients remain close to the value of bulk water even at decreasing water content. Extended diffusion approaches the thickness of the water domain and its diffusion coefficients decrease strongly with decreasing water content. A master curve links water domain thickness to the extended water diffusion coefficients for the alkaline hydrocarbon model AEM and literature data on acidic per-fluorinated Proton Exchange Membranes. Image 1 • Quasielastic Neutron Scattering (QENS) study of sub-nanosecond water transport in AEMs. • Bulk-like water diffusion on short timescales in ion exchange membranes. • Evolution of water diffusion coefficients from sub-nanosecond to millisecond timescale. • Master curve linking water domain thickness and diffusion coefficients for AEM and PEM. • Influence of water domain thickness on water diffusion. [ABSTRACT FROM AUTHOR]

Advanced alkaline water electrolysis for hydrogen production necessitates the development of new membranes with high ionic conductivity, gas-tightness, and structural robustness in the alkaline environment. To this end, a benzimidazole-linked polymer (BILP) based composite membrane is prepared by forming a BILP-101 dense layer via interfacial polymerization (IP) on top of a commercial porous polyethylene (PE) substrate membrane. The density and thickness of the dense layer are easily adjustable by changing the acid content in the aqueous phase and the IP time, respectively. The BILP-PE composite membranes exhibit an area resistance of only ∼75 mΩ cm2 at 30 °C and <30 mΩ cm2 at 80 °C in 1 M KOH. While their H 2 gas crossover rate is ∼4 × 10−14 mol cm s−1 cm−2 kPa−1, nearly two orders of magnitude lower than that of commercial Zirfon UTP-500 diaphragm. The BILP-PE membranes also show a very low swelling ratio of ∼4% and high tensile strength of >100 MPa. Soaking in 30 wt% KOH solution at 60 °C, the BILP dense layers would lose their weight at an ever-decreased speed and come to a halt after ∼24 d of soak, with a total loss of <10% of their original weight. The BILP-PE composite membrane looks very promising in advanced alkaline water electrolysis. [Display omitted] • A membrane comprises a porous organic framework layer on a polyethylene substrate. • The membrane shows low area resistance, gas crossover rate & high tensile strength. • The membrane stops further degradation after <10% weight loss in 30 wt% KOH at 60 °C. • 1 A cm−2 at 1.93 V achieved in a single cell with the membrane & 30 wt% KOH at 80 °C. [ABSTRACT FROM AUTHOR]

In order to improve the ionic conductivity and durability of anion exchange membranes (AEMs), novel ether free AEMs are prepared based on 6-bromo-1-hexanol quaternized poly(terphenyl piperidine)s by construction of a star-branched crosslinking structure via a crosslinker of 1,3,5-tris(bromomethyl)benzene. The star-branched crosslinking network enhances the dimensional stability and mechanical property without occupying the active sites for cation production. Suitable microphase separations with ionic cluster spacing within 19.68–20.72 nm are formed according to the SAXS results. The proposed AEMs exhibit hydroxide ion (OH‾) conductivity ranging from 118 to 136 mS cm−1 at 80 °C. The dense crosslinking structure and flexible side chains endow the AEMs with excellent resistance against the attack of OH‾ ions. About 80% of the conductivity retention rate is achieved after immersing the AEMs in 1 mol L−1 KOH aqueous solutions at 80 °C for 1600 h. A single H 2 /O 2 fuel cell employing the prepared membrane as the electrolyte exhibits a peak power density of 639 mW cm−2 at 60 °C without back pressure. [Display omitted] • Construction of star-branched crosslinking structure for polymer membranes. • A conductivity 136 mS cm−1 is reached at 80 °C by the prepared membrane. • Retain about 80% of conductivity after aging in 1 mol L−1 KOH at 80 °C for 1600 h. • Demonstration of the potential uses of the membranes as the electrolyte in fuel cells. [ABSTRACT FROM AUTHOR]

The composite combined Li 7 La 3 Zr 2 O 12 (LLZO) and PEO is viewed as a promising solid-state electrolyte for lithium-ion batteries due to its chemical stability, wide electrochemical window, mechanical flexibility and easy fabrication procedure. However, the primary challenges of low ionic conductivity and poor interfacial compatibility remain unresolved. Herein, a co-modified composite solid-state electrolyte based on the porous Al-doped LLZO (Al-LLZO) garnet scaffold cooperated with Ca-coordinated Dynasylan IMEO (Triethoxy-3-(2-imidazolin-1-yl) propylsilane, named DI) and PEO (denoted as CSE-DI-Ca) is reported. Benefiting from the fast lithium ion conduction in porous Al-LLZO network and interfacial strengthening modification between ceramics and polymer, CSE-DI-Ca exhibits a high ionic conductivity of 6.38✕10−4 S cm−1 at room temperature. The unique ceramic structure of CSE-DI-Ca also leads to an enlarged electrochemical window of 6 V vs. Li+/Li, good thermal stability under 360 °C, and an improved mechanical strength of 8.91 MPa to block lithium dendrites. Furthermore, as an evidence of the compatibility with high-voltage battery, the LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622)|CSE-DI-Ca|Li coin cell delivers an initial discharge capacity of 130.2 mAh g−1 at 0.1 C at room temperature and maintains a capacity of 127.3 mAh g−1 after 120 cycles. All these superior properties indicate that the as-prepared composite holds great promise as an effective solid-state electrolyte to be used in next-generation lithium-ion batteries. The composite electrolyte with a special structure is designed, in which the porous Al-LLZO scaffold prepared by polycarbonate templates shows continuous Li-ion pathways in the PEO matrix. This composite electrolyte exhibits a high ionic conductivity of 6.38✕10−4 S cm−1 at room temperature, an enlarged electrochemical window of 6 V vs. Li+/Li, good thermal stability under 360 °C, and an improved mechanical strength of 8.91 MPa to block lithium dendrites. The solid-state lithium ion batteries of the NCM622|CSE-DI-Ca|Li delivers an initial discharge capacity of 130.2 mAh g−1 at 0.1 C at room temperature and maintains a capacity of 127.3 mAh g−1 after 120 cycles. [Display omitted] • Porous Al-LLZO scaffold is prepared by polycarbonate templates. • CSE with porous Al-LLZO shows higher ionic conductivity than that with non-porous Al-LLZO. • Optimized CSE-DI-Ca shows excellent flexibility, high ionic conductivity and electrochemical stability. • CSE-DI-Ca can effectively prevent lithium dendrites piercing during a long cycle of battery. • LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622)|CSE-DI-Ca|Li coin cell delivers an initial discharge capacity of 130.2 mAh g−1 and maintains a capacity of 127.3 mAh g−1 after 120 cycles. [ABSTRACT FROM AUTHOR]

High hydroxide conductivity and sufficient dimensional/alkaline/mechanical stability are highly desired for practical applications of anion exchange membranes (AEMs). Herein, a new di -quaternized side-chain precursor (EDQA) was firstly designed and synthesized. Then novel AEMs (DBTF-4QA-x) based on poly(fluorenylene alkylene)s containing dual Y-shaped side-chains were prepared from EDQA by an efficient click reaction. Benefiting from several structural advantages of EDQA, DBTF-4QA-x membranes possessed high hydroxide conductivities up to 154.8 mS cm−1 at 80 °C, while maintained high dimensional stability. The membranes exhibited robust mechanical properties with tensile strengths and elongation at break up to 107.4 MPa and 46.4%, respectively. Furthermore, the membranes showed high alkaline stability with the conductivity loss below 11.4% after immersing in 4 M aq. NaOH at 80 °C for 40 days. In addition, DBTF-4QA-0.5 membrane achieved the maximum peak power density of 836.4 mW cm−2 in H 2 /O 2 fuel cells at 60 °C. [Display omitted] • Novel ether-free AEMs with dual Y-shaped side-chains are designed and prepared. • High ionic conductivity up to 64.8 mS/cm at 20 °C and 154.8 mS/cm at 80 °C. • High dimensional stability and good mechanical properties. • Excellent alkaline stability in 4 M NaOH at 80 °C for 40 days. [ABSTRACT FROM AUTHOR]

In alkaline environment, cationic membranes regularly experience degradation because of OH− attack on the cation in anion exchange membrane fuel cells (AEMFCs). Unlike quaternized amine (alicyclic and aliphatic) cations, aromatic cations are unaffected by Hofmann ß-elimination, however, because of planar geometry they are highly susceptible to nucleophilic substitution reaction. A series of polysulfone (PSU) based anion exchange membranes (AEMs) was fabricated carrying pendant pyridinium cation with different substituent groups to shield the cation against OH− ions attack. The pyridinium cations were C-2 substituted, C-4 substituted and simultaneously C-2 and C-6 substituted with either –NH 2 , –OH or –CH 3. Chloromethylation, azidation and CuAAC reactions were employed to synthesize the copolymers. The collaborative analysis of 1H NMR and FT-IR spectroscopy was used to confirm the successful preparation of the desired product. All membranes exhibited adequate thermo-mechanical stabilities and sufficient hydration level without any serious swelling at all ranges of temperature (20–80 °C). The highest recorded ionic conductivity, peak power density and current density were 59.6 mS cm−1, 486.8 mW cm−2 and 1481.8 mA cm−2 respectively. The alkaline stability results suggest that simultaneous protection of pyridinium cation at C-2 and C-6 turns the membrane thoroughly resistant to OH− attack while the ones with exposed cations degrade at accelerated rate at elevated temperature. This study is aimed at providing a broader understanding of designing durable AEMs with promising performance by exploring the influence of changes in structural configuration of aromatic cations with different functional groups on the overall performance of AEMs and how the cations withstand the nucleophilic attack in AEMFCs. [Display omitted] • Polysulfone based AEMs with pendant pyridinium derivatives were synthesized. • Chloromethylation and azidation were employed to functionalize the polymer. • The copolymers were synthesized via CuAAC reaction. • Simultaneous C-2 and C-6 protection of the cation resulted in High alkaline stability. • High ionic conductivity and fuel cell performance were achieved. [ABSTRACT FROM AUTHOR]

Solid-state Li-ion batteries (SSBs) are believed the new future of electrochemical energy storage, while the solid electrolyte membrane is the core part. The development of new electrolyte membrane with easy densification, high stability and high conductivity is crucial for the widespread application of SSBs. In this study, tuning the conductivity and sintering behavior of perovskite-type La 2/3-x Li 3x TiO 3 (LLTO) membranes through a co-doping strategy was proposed and systematically investigated. Specifically, the membranes with the nominal compositions of Li 0.33-y+x La 0.557-x M x Ti 1-y N y O 3 (M = Sr, Ba, Ca, N = Ta) were designed and investigated. The results demonstrated that replacement of La3+ by smaller Ca2+ decreased the bulk Li+ conductivity while substitution of La3+ by Sr2+ or Ba2+ with larger ionic radii increased the bulk Li+ conductivity. Besides, Ta5+ and Sr2+ co-doped LLTO with optimized Ta/Sr molar ratio could improve the membrane densification involving the relative density and grain size. Accordingly, a high total Li+ conductivity (1.4 × 10−4 S cm−1) with low electronic conductivity (3.2 × 10−8 S cm−1) could be achieved, and the as-prepared Li 0.33 La 0.457 Sr 0.1 Ti 0.9 Ta 0.1 O 3 membrane presented prominent electrochemical performance with a high capacity retention (89%) and Coulombic efficiency of 97% for 80 cycles, thus promised co-doping strategy for developing superior perovskite Li-ion conducting membranes for SSBs. • Perovskite Li 0.33-y+x La 0.557-x M x Ti 1-y N y O 3 (M = Sr, Ba, Ca, N = Ta) membranes were prepared systematically. • Ta5+ and Sr2+ co-doped membrane exhibited high membrane densification and low grain boundary resistance. • Li 0.33 La 0.457 Sr 0.1 Ti 0.9 Ta 0.1 O 3 showed a total Li-ion conductivity of 1.4 × 10−4 S cm−1 at room temperature. • The membrane could be cycled in solid-state Li-ion battery with a capacity retention of 89% after 80 cycles. [ABSTRACT FROM AUTHOR]

In this study, composite cation exchange membranes (C-CEMs) based on polyvinyl pyrrolidone (PVP) and mainchain sulfonated polyethersulfone (SPES) were prepared by adding conducting polyaniline (PANi). The electrodialysis (ED) properties of these C-CEMs were characterized to determine their feasibility for practical applications. C-CEMs exhibited smooth surfaces and dense cross-sections when PANi was homogeneously dispersed in the matrix material. An increase in C-CEM mechanical stability was attributed to the formation of a crosslinked structure. The experimental results showed that C-CEM with 0.6% PANi possessed the highest ionic conductivity. ED process results showed that C-CEM with 0.6% PANi exhibited better desalination properties than those of other C-CEMs and commercial CEM. On the whole, an appropriate PANi content improved C-CEM desalination properties. This study detailed a new method for the preparation of novel, low-cost C-CEMs with improved properties. It was found that a 0.6% PANi content was optimal for improving membrane performance. • A simple and economical preparation method of CEM with ideal properties was provided. • The ED properties of CEM with proper PANi were better than commercial CEM. • Polyaniline and sulfonate group play better synergistic effect on membrane property. [ABSTRACT FROM AUTHOR]

Owing to high theoretical capacity, lithium-sulfur batteries (LSBs) are receiving extensive researches. However, cyclic instability and safety issues hugely confine the commercial applications of traditional liquid LSBs. In this work, for the sake of fully leveraging the high ionic conductivity of polyacrylonitrile while avoiding Li anode "passivation effect" caused by CN group, we prepare double-layer gel polymer electrolytes for quasi-solid-state LSBs. The transition layer composed of polyacrylonitrile, polyethylene oxide and Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) is located on Li anode side to reduce "passivation effect" triggered by pure polyacrylonitrile. Meanwhile, the high ionic conductivity layer composed of polyacrylonitrile and LATP in contact with cathode can utilize the high intrinsic ionic conductivity of polyacrylonitrile to enhance the rate performance. Furthermore, LATP with higher ionic conductivity embedded in the membrane serves as Li+ transport channels to further increase ionic conductivity. Prominently, the designed double-layer electrolytes exhibit a high Li+ transference number of 0.55 and superior mechanical property. Moreover, stable coulombic efficiency of 99.6–100.0% over 100 cycles and good capacity retention of 79.0% after 100 cycles at 0.1C can be achieved. Our newly designed double-layer electrolytes with multiple functions exhibit potential applications in safer LSBs. Image 1 • The H N hydrogen bond can weaken the "passivation effect" of cyano group. • Two layers in the electrolyte possess different electrochemical functions. • High ionic conductivity layer improves the ionic conductivity of the membrane. • Transition layer protects anode from passivation caused by pure polyacrylonitrile. [ABSTRACT FROM AUTHOR]

Sodium-ion is seen as one of the most promising alternative technologies to the current lithium-ion batteries. Sodium is cheap and widely available in comparison to lithium, however new electrode and polymer electrolyte materials need to be found to improve the performance and security of sodium batteries. In this work, we show a new iongel electrolyte with excellent properties for an all solid-state rechargeable sodium batteries. This iongel membrane is based on the poly(dimethyldiallylammonium) polyDADMA-TFSI poly(ionic liquid), N -Propyl- N -methylpyrrolidinium bis(fluorosulfonyl)imide (C 3 mpyrFSI) and sodium bis (fluorosulfonyl)imide (NaFSI) the salt. PolyDADMA-TFSI can incorporate up to 50 wt% of C3mpyrFSI ionic liquid content in a self-standing membrane with high ionic conductivity. The increasing the NaFSI concentration in this electrolyte was beneficial for the sodium transference number but detrimental for the ionic conductivity of the membranes. The addition of alumina nanoparticles further improved the membrane mechanical robustness without affecting significantly the ionic conductivity. The iongel membranes presented a wide electrochemical window of 5 V thereby supporting sodium electrochemistry as demonstrated by excellent symmetric sodium cell cycling at 70 ᵒC for 60 cycles. Finally, the electrochemical performance of the optimum composition iongel was evaluated in sodium all solid-state battery using a sodium metal anode and NaFePO 4 as the cathode material. The cells show good capacity retention with high coulombic efficiency (>97%) at C rates between C/20 and C/5 achieving 110 mAhg−1 at C/20. Image 1 • Free-standing poly(ionic liquid) membrane with high sodium ionic conductivity. • The iongel membrane allows efficient sodium plating and stripping in symmetrical sodium cells. • Excellent capacity is achieved for all solid-state Na/NaFePO 4 rechargeable battery. [ABSTRACT FROM AUTHOR]

In this paper, the low molecular weight poly(p -phenylene terephthalamide) (PPTA) was introduced into the surface of integral PE network by a dip-coating and phase separation process, and a thermally stable separator with thermal-shutdown function was prepared. The pore structure of PE separator was primely retained by controlling the concentration of the casting solution. The composite separator was proved to combine thermal shutdown function and exceptional thermal stability higher than 240 °C. The polar PPTA coating and remained pore structure endowed composite separator with superior wettability, ionic conductivity and cell performance. Remarkably, the facile procedure, lower cost and excellent properties can satisfy the stringent demand of industrialization for high-performance lithium ion batteries. Image 1 • The low molecular weight PPTA which could exist in organic solvent was synthesized by low temperature copolymerization. • The PPTA-coated PE separators were prepared by a dip-coating and phase separation process. • The PPTA-coated PE separator not only restrained thermal shrinkage, but also obtained great ionic conductivity. • The PPTA-coated PE separator has an excellent thermal-shutdown function to protect the battery. [ABSTRACT FROM AUTHOR]

The effect of substituents at C2 and N3 positions of imidazolium functional group on various properties of the poly(arylene ether) ketone based anion electrolyte membranes was studied. The synthesized membranes were applied for alkaline water electrolysis using zero gap designed cell in order to evaluate their cell performances. All of the membranes exhibited better ionic conductivity and electrochemical performance than the commercial Fumasep FAA-3 membrane. The C2 methyl and N3 butyl substituted imidazolium-based membrane (PAEK-APMBI) specifically showed quite high ionic conductivity of 0.0154 S cm−1 and the voltage of 2.53 V at the current density of 2 A cm−2 (in 10 wt% KOH solution) at 60 °C, while those of Fumasep FAA-3 membrane were 0.013 S cm−1 and 2.63 V, respectively. Especially, the PAEK-APMBI membrane exhibited the excellent alkaline stability with the 96% IEC retention after long-term treatment in alkaline environment, while the Fumasep FAA-3 membrane illustrated a significant reduction in IEC to 38%. Based on those results, the PAEK-APMBI membrane would be a promising candidate for application in anion exchange membrane electrolysis system. Image 1 • A series of C2 and N3 substituted imidazolium based PAEK membranes were prepared. • Alkaline stability was significantly improved by the protection of C2 position. • PAEK-APMBI showed superior chemical stability in highly basic condition. • Flexible N3 butyl enhanced anion conductivity while maintaining lower water uptake. • PAEK-APMBI exhibited excellent electrolytic performance up to 2 A cm−2 at 2.53 V. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes have great potentials to overcome safety issues of organic liquid electrolytes for lithium-ion batteries (LIBs). However, the poor lithium-ion migration within solid polymers impedes the broad applications. In this work, composite polymer electrolytes (CPEs) are prepared by dispersing oxygen-ion conducting Sm-doped CeO 2 (SDC) nanowires into the polyvinylidene fluoride matrix. The ionic conductivity and the lithium-ion transfer number are greatly enhanced after the introduction of the SDC nanowires to CPEs, thanks to the increase of amorphous regions resulted from the SDC filler, the Lewis acid-base interaction due to the positively charged oxygen vacancies, and the partial dehydrofluorination. Specifically, CPE-10 with 10 wt% of the SDC nanowires reaches the ionic conductivity of 9.09 × 10−5 S cm−1 at 30 °C with a lithium-ion transfer number of ∼0.40. Also, CPE-10 exhibits a relatively high oxidation potential of 4.89 V versus Li+/Li. Impressively, a quasi-solid-state CR2032 LiFePO 4 /CPE-10-20 μL/Li battery exhibits the initial capacity of as high as 155.1 mAh g−1 at 1 C, and it still delivers 155.3 mAh g−1 after 130 cycles, as well as the favorable rate performance (e.g., 135.1 mAh g−1 at 4 C). Besides, a lithium-oxygen battery (Super P/CPE-10-5 wt% LiI/Li) exhibits the initial discharge capacity of 5325 m A h g c a r b o n - 1 with the coulombic efficiency of 85.7%. Our work demonstrates that CPEs with the oxygen-ion conducting SDC nanowires could be potentially applied in quasi-solid-state LIBs and lithium-oxygen batteries. Image 1 • We prepared CPEs by dispersing oxygen-ion conducting SDC nanowires into the PVDF matrix. • The ionic conductivity of 9.09 × 10−5 S cm−1 at 30 °C is achieved for CPE-10. • CPE-10 exhibits a relatively high oxidation potential of 4.89 V. • A LiFePO 4 /CPE-10-20 μL/Li battery exhibits the initial high capacity of 155.1 mAh g−1 at 1 C, and it still delivers 155.3 mAh g−1 after 130 cycles. • A lithium-oxygen battery exhibits the initial discharge capacity of 5325 m A h g c a r b o n - 1 with the coulombic efficiency of 85.7%. [ABSTRACT FROM AUTHOR]

Abstract Ion exchange membranes with high ionic contents typically suffer from excessive water uptake and dilution effects which compromise both mechanical properties and ion conductivity. In the present work we develop and compare partial quaternization, copolymerization and crosslinking as three different synthetic strategies to balance the ion exchange capacity (IEC), water uptake and hydroxide conductivity of poly(arylene piperidinium)s, which belong to a new class of alkali-stable anion-exchange membrane materials. Poly(biphenyl N -methylpiperidine) (PBPip) was first produced in a polyhydroxyalkylation reaction of biphenyl and N -methyl-4-piperidone, and then partly quaternized with controlled stoichiometric shortages of alkyl halide to regulate the IEC. In the second approach, a series of copolymers with controlled IEC were prepared by introducing precise amounts of ketone co-monomers in the polyhydroxyalkylations. In the final approach, crosslinked AEMs were fabricated in a reactive casting procedure, followed by partial quaternization. The overall results of the study reveals that the copolymerization approach gives AEMs with the most attractive set of properties. Hence, at a given IEC and moderate water uptake, the copolymer AEMs reach the highest hydroxide conductivity, up to 120 mS cm−1 at 80 °C, and retain the high alkaline stability of the original poly(arylene piperidinium) AEM. The study demonstrates the versatility and efficiency of these synthetic strategies to tailor and significantly improve the properties of functional high-performance AEMs for different electrochemical applications. Graphical abstract fx1 Highlights • Poly(arylene piperidinium)s are ether-free polymers with high alkaline stability. • Different synthetic strategies to control the ionic content are developed and evaluated. • Copolymerization provides the most attractive fuel cell membrane properties. • We demonstrate the potential of various approaches to high-performance membranes. [ABSTRACT FROM AUTHOR]

Abstract A series of highly alkaline durable crosslinked anion exchange membranes (AEMs) is prepared via elimination reaction using a sodium salt of 4,4′(5′)-di(hydroxybenzo)-18-crown-6 as the crosslinker, and quaternary ammonium (QA) as the cation group. The ionic conductivity, ionic exchange capacity (IEC) and mechanical property of the AEMs are investigated. The highest ionic conductivity (about 117 mS cm−1) of the PPO-CE 0.10 -QA 0.90 membranes is obtained at 80 °C and 100% relative humidity. The alkaline stability of the AEMs is determined by inspecting the decline in ionic conductivity, mechanical property and the change in chemical structure after the alkaline stability test. The ionic conductivity has only a 6.0% decrease, the tensile strength has an 11.8 MPa reduction and the elongation at break has a 2.7% depression after 480 h test in 2 M KOH at 80 °C. 13C NMR spectra confirm a negligible change in chemical structure of the AEMs after the alkaline resistance test. The peak power density (about 195 mW cm−2) is achieved under a current density of 350 mA cm−2 at 80 °C. Additionally, the AEMs with a novel crosslinked structure decompose above 230 °C and exhibit decent thermal stability. Graphical abstract Image 1 Highlights • Novel AEMs were fabricated using crown ether as crosslinker. • Crown ether can promote the microphase separation of AEMs. • Crown ether as crosslinker can improve the mechanical property. • Crown ether as crosslinker can enhance alkaline stability of the AEMs. [ABSTRACT FROM AUTHOR]

Abstract Tailor-made star polymers comprised of cross-linked cores containing polymeric pseudo-crown ether cavities and linear poly(ethylene oxide) (PEO) arms are designed via cation template-assisted cyclopolymerization. The pseudo-crown ether cavities in cross-linked cores can coordinate with alkali metal cations and offer more cation diffusion channels. Moreover, the functional linear PEO arms are beneficial to the conductivity of cations and increase the compatibility with the PEO matrix. By selecting monomers with different chain lengths and cation templates, the tailor-made star polymers can be employed as efficient conductors for lithium-ion, sodium-ion, and potassium-ion batteries. The lithium-ion conductivity of the solid-state polymer electrolytes obtained from a potassium cation template and poly(ethylene glycol) dimethacrylate (PEGDMA750) monomer (K-SPE750-Li) is 2.82 × 10-5 S cm-1 at 20 °C. Furthermore, the cell of Li|K-SPE750-Li|LiFePO 4 shows stable cycling performance and a good rate property. Graphical abstract fx1 Highlights • Star polymers with pseudo-crown ether cavities. • Remarkable ionic conductivity of polymer electrolytes at room temperature. • Stable charge/discharge performance with initial discharge capacity. [ABSTRACT FROM AUTHOR]

Abstract Flexible composite polymer electrolytes (CPEs) are fabricated by reversible addition-fragmentation chain transfer (RAFT) polymerization of poly(ethylene glycol) methacrylate (PEGMA) and poly(ethylene glycol) diacrylate (PEGDA), followed by physical doping with ionic bond modified nanoparticles (IBNs) based on nanoscale silica. In reference to PEGMA-PEGDA cross-linked framework prepared by ultraviolet light irradiation directly, RAFT polymerization endows the electrolyte membranes with excellent flexibility, and further increase in yield stress and tensile modulus achieved with IBNs adding in the system. CPEs obey Arrhenius law and its ionic conductivity is found to be maximum of 6.77 × 10−5 S cm−1 at 30 °C, but that of the electrolytes consisted of the same molar feeding ratio of PEGMA/PEGDA without IBNs blending is 3.76 × 10−5 S cm−1 at 30 °C, indicating that the loading of IBNs improves the ionic conductivity, due to the elevated chain mobility. Besides, the electrochemical stability of CPEs is promoted in comparison with the traditional linear poly(ethylene oxide) (PEO) based electrolytes. Moreover, the electrolyte membrane exhibits good cycling performance with lithium iron phosphate and retained 94.3% of capacity after 40 charge-discharge cycles, demonstrating the great potential of this kind of CPEs prepared in this study as electrolyte materials for battery systems. Graphical abstract fx1 Highlights • Silica coated polyether with sulfo-amino ionic connection. • Remarkable ionic conductivity of polymer electrolytes at room temperature. • Excellent flexibility with good mechanical properties. [ABSTRACT FROM AUTHOR]

Abstract Under strong oxidative environment of vanadium redox flow batteries (VRFB), membrane instability is a serious challenge. Anion exchange membranes (AEMs) are expected to reduce vanadium ion permeability due to Donnan exclusion. Herein, we report long alkyl chain grafted quaternized graphene oxide bonded poly(ether sulfone) by 1,4-diazabicyclo[2,2,2]octane (DABCO) coupling, which provides plenty of amine groups. This helps to improve the ionic conductivity. Whereas, long alkyl chain (C16) grafted quaternized graphene oxide causes well phase separation (hydrophilic-hydrophobic) and decent ionic pathway for ionic transportation. The reported AEMs showed good stabilities under harassed acidic/oxidative conditions due to the bulky nature of chemically grafted QG with the main polymer backbone. This results steric hindrance to resist the attack of oxidative species. Suitably optimized PS-DTQG-5 AEM, showed 32.46% water uptake, 2.14 meq/g ion exchange capacity, 6.06 × 10−2 S/cm ionic conductivity, and 18.93 × 105 S min cm−3 selectivity for VRFB. The VRFB assembled with PS-DTQG-5 AEM, displayed extremely good efficiencies (coulombic (98.06%), energy (76.4%), and voltage (78.0%)) at 60 mA cm−2, higher than those for Nafion 117 membrane. Further, stabilities under ex-situ oxidation conditions and in-situ cycle test (approx. 80) in VRFB operating environment make PS-DTQG-5 AEM as an attractive candidate. Graphical abstract fx1 Highlights • Grafting of quaternized graphene oxide containing C16 chain by DABCO coupling. • Acid/oxidative stable AEMs based on poly(ether sulfone) with plenty of amine groups. • AEMs with good conductivity and impervious for vanadium ion due to Donnan exclusion. • Well-architected PS-DTQG-5 membrane with good efficiencies and durability for VRFB. [ABSTRACT FROM AUTHOR]

Abstract Developing highly ion conductive and desirable electrodialysis (ED) performance anion exchange membranes (AEMs) is of great significance. In this work, we report a strategy for fabricating novel AEMs based on a series of fluoro-methyl poly(arylene ether ketone)s having long-side-chain imidazolium groups for ED. Having hydrophilic conductive flexible side-chain imidazolium groups and rigid hydrophobic backbone within AEM matrix, the optimized AEM (PAEK-60-im) shows low water uptake of 24.9% at 80 °C and desirable ion conductivity of 22.01 mS cm–1 at 30 °C. In NaCl removal application of ED, PAEK-60-im shows the NaCl removal ratio of 69.66% within 120 min, outperforming commercial AEM-Type II (68.98%). Accordingly, it has a higher current efficiency of 83.7% but lower energy consumption of 5.9 kWh kg–1, compared with the commercial one (82.0%; 6.6 kWh kg–1). In particular, in selectrodialysis application, possibly owing to the synergistic effect of pore-size sieving effect resulting from macro-separation morphology and hydration energy difference of SO 4 2– ions (–1000 kJ mol–1) and Cl– ions (–317 kJ mol–1) in feeding solution, PAEK-60-im shows significantly superior monovalent anion perm-selectivity (Cl−/SO 4 2−) of 7.70 at 30 min, relative to commercial anion-selective Neosepta ACS (5.27) and many other reported mono-valent anion selective AEMs having elegant surface modified layers. The superior ED performance of the homogeneous PAEK-60-im is suggestive of its potential separation application. Highlights • Imidazolium-functionalized fluoro-methyl poly(arylene ether ketone) AEMs have been prepared. • The optimized AEM shows water uptake of 24.9% at 80 °C and ion conductivity of 22.01 mS cm–1 at 30 °C. • The NaCl removal ratio within 2 h of optimized AEM is 69.66%, outperforming that of AEM-Type II (68.98%). • The optimized AEM has a significantly high perm-selectivity (Cl-/SO 4 2-) of 7.70 at 30 min in selectrodialysis. [ABSTRACT FROM AUTHOR]

Abstract The mechanical, structural and ionic conductivity properties of the polymeric composite membranes are elucidated here according to the weight% amount of inorganic additives. 3 M PFSA (perfluorosulfonic acid) polymer, borosilicate glass particles coated with nanoparticles and sulfuric acid (H 2 SO 4) as functionalized solid inorganic additives (FSIA) are used to improve the overall properties. Wide–angle X-ray diffraction (WAXS) results elucidated the presence of both non-crystalline and crystalline ordered-disordered hydrophobic regions. In the presence of water, the size of the crystalline domains increased which help to increase the crystallinity. The dynamic mechanical analysis (DMA) results indicate the improved mechanical stability of the polymeric composite membranes and the results are consistent with the suggestions that dynamic cross-links [R-SO 3 H.... (SiO 2)] density is higher in the composite membranes and supports to enhance the properties without compromising ionic conductivity unless the amount of FSIA exceeds 3 weights (wt.) %. The coating of nanoparticles made an excellent interface between FSIA and polymer matrix as observed in SEM analysis and block the movement of other ions such as SiO 2 , Na+, K+ which could also participate in overall ionic conductivity. Moreover, as a result, the mobility of polymer side chains increased in conjunction with water-FSIA-H 2 SO 4 because of strong hydrogen bonding, which help to improve the ionic conductivity of final polymer composite. Graphical abstract fx1 Highlights • 3 wt% FSIA additives helped to improve mechanical strength and crystallinity. • Nano-particles coating helped to make an excellent interphase between FSIA and polymer matrix. • Surface functionality improves the overall mechanical and ionic properties of PFSA composites. • FSIA helps in prevention of ion-exchange from glass particles to the proton conductive polymer. • FSIA helps to improve overall ionic conductivity at high temperature and low humidity. [ABSTRACT FROM AUTHOR]

Abstract Acid resistant proton exchange membranes (PEMs) are synthesized from aliphatic highly hydrophobic polyvinylidene-co-hexafluoropropylene (PVDF-co-HFP) and aromatic hydrophilic sodium- p -styrene sulfonate at nanostructure level modification. Synthesized copolymer PEMs are analyzed for their chemical structure to confirm the presence of functional groups. Electrochemical characterizations are carried out in terms ion-exchange capacity, ionic conductivity and water content. Maximum IEC value 1.91 meq/gm is observed for PDSt-40 copolymer PEM with 1.58 × 10−2 S/cm proton conductivity and 29.1% of water content. Vanadium ion permeability is also checked for copolymer membranes in terms of applicability for vanadium redox flow batteries. PDSt-40 copolymer PEM shows lowest value of VO2+ ion permeability 2.87 × 10−7 cm2 min−1, which is about 40% less compared to Nafion membrane. Further all synthesized PEMs are checked for charging-discharging performance for single cell VRFB. PDSt-40 PEM shows better performance in term of columbic and voltage efficiency. Copolymer membranes found to be stable thermally and mechanically and also in harass condition with 18 M H 2 SO 4 for 24 h. Results indicate that synthesized copolymer PEMs can be a good candidate for electrochemical energy systems as well as high temperature applications. Highlights • Acid resistant proton exchange membranes (PEM) have been successfully synthesized by (PVDF-co-HFP) and sodium- p -styrene sulfonate. • Copolymer PEM shows better electrochemical properties. • Thermal and mechanical stability of the membrane found to be comparable as per the bench mark membrane. • PDSt-40 PEM show lowest value of VO+2 ion permeability 2.87 × 10−7 cm2 min−1, which is about 40% lesser then Nafion 117 (4.76 × 10−7 cm2/min). Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

Abstract The ionic liquid (IL) incorporated hybrid membranes were synthesized via sol-gel process to simultaneously act as a separator and functionalized gel polymer electrolytes (GPEs). These IL functionalized hybrid GPEs provide an adequate ionic conductivity of 6.0 mS cm−1 at 30 °C and good electrochemical stability up to 5.0 V. Moreover, the differential scanning calorimetry (DSC) results demonstrated that the IL group hardened the polymer chain without liquid electrolytes. However, the glass transition temperature (T g) dramatically decreased when liquid electrolytes were incorporated, which means the polymer has good affinity for carbonate electrolytes and good ionic transport ability. Further, the immobilized cationic group anchored in the polymer matrix can be seen as a Lewis acid; thus, it interacts with the PF 6 - anion and enhances the lithium transference number from 0.28 to 0.57. In addition, compared to the GEP without the IL group (SiEO), the GPE with high IL group (ImEO51) shows relatively superior battery performance. For the Li/GPE/LiFePO 4 battery application, cell capacities of both SiEO and ImEO51 were close to 150 mAh g−1 at 0.1 C. However, at high current density of 5 C, the capacities of ImEO51 can reach 90 mAh g−1, significantly higher than that without the IL group (35 mAh g−1). Therefore, the aforementioned properties of the IL functional GPEs can be a potential alternative polymer electrolyte for high-performance rechargeable lithium ion batteries. Highlights • The ionic liquid functionalized hybrid GPEs provide an adequate ionic conductivity of 6.0 mS cm−1 at 30 °C. • High cell capacity under different C-rates and high electrochemical stability. • The immobilized cationic of the polymer matrix act as a Lewis acid to enhance lithium transference number. [ABSTRACT FROM AUTHOR]

Abstract Mixed oxide-ion and electron conductors (MIECs) are a scientifically and technologically important class of functional materials for energy conversion and storage. The present work reports a study on transport properties of two well-known MIECs, SrCo 0.9 Nb 0.1 O 3-δ (SCN) and SrCo 0.9 Ta 0.1 O 3-δ (SCT), using a combined experimental oxygen permeation measurement and theoretical modeling approach. The results suggest that SCN has a higher oxygen diffusivity, surface oxygen exchange rate constant and oxide-ion conductivity than SCT even though both materials have the same crystal structure. A molecular orbital energy analysis reveals that the slight difference in outer electronic shell configuration between Nb5+ and Ta5+ is responsible for the variance in transport properties. Highlights • Attainment of bulk oxygen diffusivity and partial oxide-ion conductivity. • Attainment of surface oxygen exchange rate constant. • Elucidation of fundamental reason determining oxygen transport. [ABSTRACT FROM AUTHOR]

Abstract Lithium 4,4′-difluorobenzene sulfonyl imide is copolymerized with polyethylene glycol (PEG, M w = 200, 400, 600, 800 and 1000) to synthesize a series of AB alternating diblock copolymer electrolytes (ADCE-1, 2, 3, 4, 5) for reducing the crystallinity of solid-state single ion conducting materials for applications in all-solid-state lithium metal secondary batteries. The free-standing film of ADCE-5 with the highest [EO]/[Li+] ratio (23.7:1) is found to display the lowest glass transition temperature (T g) and the highest ionic conductivities of 6.61 × 10−6 S cm−1 at 30 °C and 2.24 × 10−4 S cm−1 at 100 °C. The alternating architecture of the polymer effectively prevents the polymer from phase separation originated from aggregation of the ionic groups as well as the ethylene oxide groups. As a result, segment motion may take place readily in the amorphous region at low temperature. Subsequently, a piece of glass fiber mat reinforced composite polymer electrolyte film is prepared for practical battery tests. The fabricated all-solid-state single ion conducting polymeric lithium metal secondary battery is able to work at a temperature as low as 40 °C with stable cycling performance. The battery delivers 102 mA h g−1 at 0.1 C and is stabilized at 94 mA h g−1 after 200 cycles. Highlights • The AB alternating configuration interrupts the homogeneity of the main chain. • The phase transition temperatures of copolymers vary reversibly with that of PEGs. • 1.29×10-5 S cm-1 at 40 °C and t + =0.86 for the polymer electrolyte membrane. • An all-solid-state single ion conducting lithium metal battery is demonstrated. [ABSTRACT FROM AUTHOR]