Search

Gel polymer electrolytes (GPEs) based on poly(1,3-dioxolane) (PDOL) have been developed due to their excellent lithium metal compatibility and convenient in-situ polymerization synthesis. A PDOL-based GPEs is obtained by in-situ polymerization, in which introduce Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (LLZTO) solid-state fillers and Succinonitrile (SN) functional additives, named as PDOL-SN/LLZTO. The PDOL-SN/LLZTO exhibits high ionic conductivity of 5.19 × 10–3 S cm-1 and high lithium-ion transference number (t Li +) of 0.79 at room temperature, as well as expanded electrochemical window of 4.85 V. For Li||Li symmetric cells, it achieves stable cycling over 2000 hours at a current density of 0.1 mA cm-2. Benefiting from the enhanced interfacial stability due to LLZTO doping, Li||LiFePO 4 cells provide a high initial capacity of 146.3 mAh g-1 at 1C, with a capacity retention of 84.5% after 1000 cycles at 1C. So, the glass fibre-based PDOL provides an important approach and facile strategy for designing high-performance lithium-metal batteries. [ABSTRACT FROM AUTHOR]

Efficient operation of electrochemical energy devices below freezing point poses a significant challenge for enhancing their environment adaptability. This issue is particularly critical for quasi-solid-state devices those utilize gel polymer electrolytes (GPEs), since low temperature could enhance polymer crystallization in GPEs, inducing external steric hindrance that impede ionic conductivity. Herein, we utilized polyhedral oligomeric silsesquioxanes (POSS) as the eight-armed cross-linking points in an in-situ photopolymerized network, thereby constructing low-temperature tolerance GPEs for dye-sensitized solar cells (DSSCs). Compared to conventional triple-armed cross-linking, POSS could increase the disorder of the polymer network and significantly lower the glass transition temperature of the GPE from -30 °C to -48.7 °C. At an ultralow working temperature of -40 °C, the POSS-linked GPEs show a high ionic diffusion coefficient of 0.71 × 10–6 cm2 s-1 compare to that of liquid electrolyte, ensuring that the quasi-solid-state DSSCs successfully retained 36.3 % of their room-temperature efficiency. Our work proved a design method for the low-temperature tolerance GPEs, which could enable the advanced electrochemical application in harsh climates, such as sensor, energy generation, and storage devices. [ABSTRACT FROM AUTHOR]

• Quasi-solid-state Zn-air batteries with high performance require interface modifications. • Gel polymer electrolytes (PVA/PAA) were obtained by incorporating SiO 2 nanospheres. • Interface was also modified by synthesizing a CoMn 2 O 4 spinel as substitute to Pt and Ir. • SiO 2 size greatly influenced the battery performance. • The interface engineered battery presented 2 times more stability in charge/discharge cycles. Rechargeable zinc–air batteries (RZABs) with high energy densities and low costs have attracted tremendous interest for meeting the ever-growing demand for flexible and portable applications. In these batteries, the quasi-solid/solid-state electrolyte plays a critical role in the battery performance, such as the cycling performance rate and power output. In this study, porous poly (vinyl alcohol) (PVA) and poly (acrylic acid) (PAA) composite gel polymer electrolytes (GPEs) were modified by incorporating SiO 2 as a water retainer. For this reason, SiO 2 spheres of different sizes were synthesized by varying the temperature (5, 20, 60, and 80 °C) and reaction time (2, 6, 18, and 24 h). According to the SEM micrographs, the average size ranged from 107 to 710 nm depending on the conditions. The porous PVA/PAA–SiO 2 GPEs obtained by selecting three SiO 2 sizes (107, 425, and 630 nm) exhibited higher water retention capability than the unmodified GPE. Among them, the GPE with SiO 2 –630 nm displayed the highest battery performance (1.46 V, 85 mWcm−2 @ 0.8 V). This was achieved using CoMn 2 O 4 spinel as a bifunctional electrocatalyst, with a catalyst loading of 2 mg cm−2. The quasi-solid-state RZAB displayed twice the rechargeability of the RZAB assembled with Pt/C+IrO 2 /C (120 vs. 62 cycles). According to post-mortem tests, this can be related to the improved water retention, the decrease in the size of the formed Zn dendrites, and the stability of the bifunctional material. Thus, fine-tuning of the electrocatalyst/electrolyte interface strongly affects the rechargeability. [Display omitted] [ABSTRACT FROM AUTHOR]

• MnO 2 -rGO composites, synthesized in different MnO 2 :rGO ratios for applications as cathode materials in Zn-air batteries. • The synthesized materials, tested in lab made zinc-air battery devices using gel polymer electrolyte. • The optimized MnO 2 -rGO composite (1:1) exhibited a cycle life ∼3 times higher (165 h@5.2 mA/cm2) than bare MnO 2 NWs and ∼2 times than other composite forms and a specific capacity of 731 mAh/g Zn. • Reduced graphene oxide enhances the conductivity, specific surface area and active sites for catalysis, whereas α-MnO 2 effectively catalyze the oxygen reduction and evolution reactions. A high-performance and long-lasting, rechargeable Zn-air battery requires a reliable and effective bifunctional catalyst material to facilitate the oxygen reduction and oxygen evolution reactions during the battery operation. Manganese oxide (MnO 2) is a promising non-precious perspective due to its multivalency and various polymorphic structures that effectively catalyze oxygen evolution and reduction. In the present work, MnO 2 nanowires (NWs) have been integrated with over-reduced graphene oxide (rGO) in various concentrations via a facile hydrothermal route. The synthesized materials, tested in lab-made zinc-air battery devices fabricated using gel polymer electrolyte, exhibit a significant enhancement in the performance and 2–3 times the cycle life compared to the bare MnO 2. The ZAB device was tested for galvanostatic charge-discharge technique, and results exhibit a cycle life of 165 h (495 cycles@20 min per cycle) when discharged up to 1.0 V at a current density of 5.2 mA/cm2 and displayed a capacity of 731 mAh/g Zn. Reduced graphene oxide acts as a support material that enhances the conductivity and surface area of the active material and also provides active sites for catalysis. This work signifies the importance of the engineering of the catalyst, support material, and additives, as slight changes may result in a significant enhancement in the cycle life.The appropriate composition of catalyst and support material and a compatible gel polymer electrolyte facilitates the fabrication of flexible zinc-air batteries for various applications. [Display omitted] [ABSTRACT FROM AUTHOR]

In the photovoltaic market, the widespread adoption of traditional dye-sensitized solar cells (DSSCs) faces obstacles due to inherent stability challenges. The solution to these issues involves replacing liquid electrolytes with quasi-solid electrolytes. In this work, quasi-solid state electrolytes were synthesized by employing a polymer blend and inorganic salt. The polymeric blends, comprising polymethyl methacrylate (PMMA) and polyvinylidene fluoride (PVDF), were meticulously prepared through the solution blending technique. The investigation of blend compatibility, crystallinity, and stability involved analyses through differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-degradation assessments, respectively. The findings indicated that the concentration of ingredients significantly influenced the compatibility, crystallinity, and stability of the blends. The compatibilized blend was employed in crafting polymer gel electrolytes (PEGs), demonstrating that both the concentration and type of salts significantly influence the ionic conductivity of PEGs. The highest conductivity, reaching 2 mS/cm, was achieved with a mixed salt concentration of 50w%/50w% (NH 4 I/KI). Subsequently, this electrolyte was incorporated into the fabrication of quasi-solid state DSSC. The results showed that the DSSC with PEG achieved 2.81 % efficiency, while the traditional DSSC had 4.11 % efficiency. Notably, after fifteen days, the efficiency of the traditional DSSC dropped to 0.20 %, while the PEG-based DSSC remained stable (2.58 %). [ABSTRACT FROM AUTHOR]

Nowadays, varied application environments require lithium-ion batteries to have self-healing capabilities so that they can avoid the breakage caused by volume changes during using and reach better safety, reliability, and longer cycle life. Herein, an ionic liquid filled polymer gel electrolyte IL-PEO was proposed, prepared by a simple method and process, the gel electrolyte exhibits significantly enhanced mechanical strength and demonstrates good resistance to heat, high ionic conductivity (1.05 × 10−3 S cm−1, 30°C) and Li transference number. The research show that the addition of BMIM-TFSI promoted the construction of SEI layer and effectively inhibited the growth of lithium dendrites in the gel electrolyte. The LiFePO 4 / Li cells with IL-PEO-10 exhibited excellent cycling performance (initial specific capacity of 161.3 mAh g −1 and 94 % capacity retention after 100 cycles) and good rate performance. Most importantly, IL-PEO is able to heal the damage in LiFePO 4 / Li batteries at 25 °C and restore the performance, thus improves the stability and safety of the batteries. [ABSTRACT FROM AUTHOR]

Biopolymer electrolyte-based electrochemical devices for charge storage, such as supercapacitors and rechargeable batteries, attract wide attention. This study proposes that thin, transparent, and flexible polymer electrolytes can be fabricated using pectin, poly (ethylene glycol) (PEG), and calcium chloride (CaCl 2) by solvent casting. CaCl 2 plays a vital role as a crosslinker to form the film. The developed pectin/CaCl 2 (PeO) and PEG/pectin/CaCl 2 (PPe) polymer films are subjected to Fourier transform infrared analysis (FTIR) to confirm polymer matrix formation with the salt ions. The biopolymer membrane's glass transition temperature (Tg) is analyzed using differential scanning calorimetry (DSC). Symmetric supercapacitor devices were fabricated using activated carbon (AC) as electrode material, functionalized carbon fiber as a current collector, and pectin polymer films (PeO and PPe) as a gel electrolyte/separator. The symmetrical device with AC as the electrode and PPe as the electrolyte [AC||PPe||AC] exhibited a specific capacitance of 879 mF cm−2 at 15 mA cm−2, which is considerably higher than the similar device with PeO as electrolyte [AC||PeO||AC]. The cyclic stability of the [AC||PPe||AC] supercapacitor device was 83 % over 5000 cycles. Three supercapacitor devices connected in series is capable to glow 5 light-emitting diodes (LEDs). Good storage and stability indicate that the PPe is suitable as a gel polymer electrolyte material. This polymer electrolyte has excellent prospects in practical applications of all-solid-state, flexible, portable, and biocompatible energy storage devices. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, a quasi-solid-state supercapacitor with high energy density was successfully developed using a zwitterionic gel electrolyte with a dual-function redox additive. A polyzwitterion charged polymer, poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide) (PPDE), was used with LiCl as the flexible gel electrolyte. This proposed electrolyte demonstrates promise for use in practical supercapacitors due to its environmental friendliness, transparency, flexibility, and high ionic conductivity. To further improve the electrochemical performance, a dual-function redox additive, ethyl viologen dibromide, was incorporated into the polyzwitterion. With the redox mediator in the polyzwitterionic electrolyte (PPDE-LiCl-EV), the specific capacitance improved by a factor of three compared to the pristine zwitterionic polymer (178 F g−1 for PPDE-LiCl and 677 F g−1 for PPDE-LiCl-EV) due to additional faradaic reactions. In addition, a quasi-solid-state supercapacitor incorporating PPDE-LiCl-EV exhibited a high energy density of 542 Wh kg−1 and a power density of 2.88 kW kg−1 over a wide potential window of 2.4 V. Fourier transform infrared spectroscopy in attenuated total reflectance mode was employed for in situ monitoring of the redox reactions of additives on the electrode surface. To the best of our knowledge, this is the first attempt to analyze the redox reactions of redox additives. Image 1 • An flexible, transparent and high voltage gel electrolyte is proposed. • Zwitterionic polymer is used for polymer matrix to give high ionic conductivity. • Outstanding energy density of 542 Wh kg-1 at power density of 2.88 kW kg-1 was achieved. • By introducing ethylviologen dibromide, capacitance was significantly enhanced. • Directly monitoring the redox-reaction by in-situ ATR-FTIR. [ABSTRACT FROM AUTHOR]

We demonstrate the electrochemical performance of a lithium-polymer battery comprising P(VDF-HFP) nanocomposite membrane based gel polymer electrolytes (GPE). The nanocomposite membranes are prepared by incorporating ionic liquid functionalized ZnS nanoparticles on to P(VDF-HFP) copolymer. Soaking the membranes into lithium salt dissolved liquid organic solvents transform them into GPEs. Increasing the nanoparticles content gradually improves the porosity and the solvent uptake capacity of the membrane. The optimized membrane with 64% porosity shows highest electrolyte uptake ability of 89% to form a flame-retardant GPE endowing a maximum ionic conductivity of 3.3 mS cm−1 at ambient temperature along with an excellent lithium ion transfer number of 0.62. The cell comprising the optimized GPE with LiFePO 4 cathode and Li metal anode shows outstanding electrochemical performance at ambient temperature, delivering a discharge capacity of ∼161 mAh/g at C/10 rate and able to retain its 89% after 50 cycles. The study suggests that conjoining ionic liquid tethered nanoparticles with insulating polymers provides a promising way to produce efficient active polymer membranes based high-performance GPEs, enabling safer, high energy density, lithium-polymer batteries. [ABSTRACT FROM AUTHOR]

Quasi-solid-state dye-sensitized solar cells from polymer gel electrolytes are promising candidates to stabilize the photovoltaic performances. We demonstrate here the synthesis of a conducting gel electrolyte with gradient polyaniline-graphene/PtNi distribution and redox iodide/triiodide couples in a three-dimensional poly(acrylic acid)-poly(ethylene glycol) matrix. Through sandwiching poly(acrylic acid)-poly(ethylene glycol)/polyaniline-graphene/PtNi gel electrolyte with a dye-sensitized TiO 2 photoanode and a PtNi counter electrode, the electrons flow from PtNi counter electrode to conducting gel electrolyte along gradient energy levels for reducing triiodide ions and shortening charge diffusion length. These gradient quasi-solid-state dye-sensitized solar cells achieve a maximized power conversion efficiency of 8.64% in comparison with 7.41% for the device with homogeneously distributed polyaniline-graphene/PtNi, not to mention 5.92% for poly(acrylic acid)-poly(ethylene glycol) tailored solar cell free of polyaniline-graphene/PtNi. Moreover, the optimized quasi-solid-state dye-sensitized solar cell presents a relatively high stability at room temperature over 10 days. Image 10111137 • PANi-G/PtNi is imbibed into PAA-PEG framework assisted by magnetic field. • The PANi-G/PtNi has a gradient distribution in gel electrolyte. • The PAA-PEG/PANi-G/PtNi electrolyte presents gradient work function. • The gel electrolyte presents catalytic activity toward triiodide reduction reaction. • The quasi-solid-state DSC shows maximized efficiency of 8.64%. [ABSTRACT FROM AUTHOR]

Despite four decades of effort the promise of polymer matrices as hosts for highly mobile ionic species has not been realized. Initially a problem caused by the binding of cations to the basic oxygens of polyether type backbones, and partly solved by strategies that yield conductivities some ten orders of magnitude larger than expected from polymer backbone relaxation times at their T g , the polymer electrolytes still fail to yield the target conductivity of 10−2 S/cm at ambient temperature, unless used in the gel form in which the ion motion occurs in a liquid medium out of reach of the dilute polymer chains. We review the different attempts made in our lab and others to achieve a complete decoupling of ion motion from segmental relaxation. Concluding that there is some fundamental problem in the original salt-in-polymer solvent (and anionic polymer) physics, due to the ion proximity to the mobility-limiting polymer chains, we look to other ways of employing the strength of polymer materials while supporting ionic conducting phases of high intrinsic conductivity. Our best answer, to date, is an alkali ion-conducting plastic solid phase that can be impregnated into a tough microporous membrane, such as Celgard, of pore dimensions such that the large majority of the alkali cations see only free anions in the course of their migration from cathode to anode, during discharge and recharge of electrochemical devices. [ABSTRACT FROM AUTHOR]

Abstract We report a novel configuration of electrical double layer capacitors (EDLCs), fabricated with porous activated carbon electrodes derived from bio-waste pinecone and plastic crystals-based gel polymer electrolytes. Different activated carbons have been produced by activating raw pinecone powder employing different amount of activating agent ZnCl 2. Optimization of morphology, structure and porosity parameters of activated carbons has been performed by scanning electron microscopy, x-ray diffraction, Raman and porosity analyses. Mixed (micro- and meso-) porous interiors in activated carbon show optimum characteristics of EDLCs. Gel polymer electrolyte comprising mixture of non-ionic plastic crystal and organic ionic plastic crystal (succinonitrile and 1-ethyl-1-methyl pyrrolidinium bis(trifluoromethyl sulfonyl)imide, respectively) entrapped in poly(vinylidene fluoride-co-hexafluoropropylene) has been found suitable to fabricate EDLCs owing to their flexible nature, high ionic conductivity (σ ∼1.53 × 10−3 S cm−1 at room temperature) and wide enough electrochemical stability window, ESW (∼3.1 V versus Ag). Addition of Li-salt in the gel polymer electrolyte improves the electrochemical properties (σ ∼2.87 × 10−3 S cm−1 and ESW ∼3.8 V) and found to influence the performance of the EDLCs, particularly, the specific power, significantly. The EDLC cell with Li-salt containing electrolyte offers higher values of specific capacitance, energy and power (∼255 F g−1, ∼20 Wh kg−1 and ∼55.7 kW kg−1, respectively) than the cell with electrolyte without Li-salt (∼244 F g−1, ∼19 Wh kg−1 and ∼39.3 kW kg−1, respectively). The EDLC (with Li-salt electrolyte) exhibits 96–100% Coulombic efficiency and almost stable specific capacitance for ∼20,000 charge-discharge cycles after only ∼11% initial fading. The capacitor gives stable performance for a wide temperature range from −30 to 90 °C. [ABSTRACT FROM AUTHOR]

Abstract Gel polymer electrolyte (GPE) is considered to be a promising electrolyte to realize flexible and safe lithium-based batteries. However, the potential is severely hindered by low ionic conductivity under room temperature, undesirable mechanical property and unstable thermal performance. Herein, these puzzling issues can be effectively settled by constructing a 3D cross-linked network GPE through in-situ polymerization methyl methacrylate (MMA) and ethoxylated trimethylolpropane triacrylate (ETPTA) monomers on electrospun polyacrylonitrile (PAN) nanofibers. The shape conformable GPE presents a high ionic conductivity (0.33 mS cm−1 at room temperature), extended cycling stability even at high temperature and excellent ability to restrain the growth of the lithium dendrite. Consequently, Li|GPE|LiFePO 4 cell shows 134.8 mAh g−1 initial discharge capacity and maintains 78.6% capacity retention after 600 cycles at 2 C under room temperature. More significantly, 112.3 mAh g−1 discharge capacity is still achieved at 2 C and under 50 °C after 300 cycles, which is far more superior than liquid electrolyte with PAN substrate separator. Notably, pouch cells remain working under bending and cutting conditions showing excellent flexibility. The eminent performances provide a promising and alternative way in electrolyte fabrication for lithium-based batteries. Highlights • A flexible gel polymer electrolyte (GPE) is successfully obtained by in-situ polymerization MMA and ETPTA monomers. • The GPE possesses high ionic conductivity of 0.33 mS cm−1 at room temperature. • Li.|GPE|LiFePO 4 cell with superior thermal stability still achieved 112.3 mAh g−1 discharge capacity at 2 C and at 50 °C after 300 cycles. [ABSTRACT FROM AUTHOR]

Abstract In this work we have demonstrated how to prepare a novel gel polymer electrolyte (GPE) with remarkable adhesive characteristics by combining a synthesized poly(ionic liquid) consisting of poly(1-vinyl-3-propylimidazolium bis(fluorosulfonyl)imide) (poly(VPIFSI)) and a commercial ionic liquid: 1-ethyl-3-methyl imidazolium bis(fluorosulfonyl)imide (EMIFSI). For this purpose several PIL/IL-GPEs systems (considering the amount of IL) were subjected to electrochemical characterization. The influence of the PIL/IL-GPE (50 wt% of IL) on the properties of a flexible solid state supercapacitor was evaluated using electrochemical impedance spectroscopy, cyclic voltammetry and the galvanostatic charge/discharge technique that allows synchronous measurements of the cell voltage and the potential of the positive and negative electrodes. The influence of the ions on the formation of the electric double layer in the device during cycling employing different conditions and folding angles is discussed. The properties of the adhesive PIL/IL-GPE, such as high conductivity, good interaction between the PIL matrix and the IL liquid phase that prevents any leakage (thereby contributing to greater safety) together with the good adherability and wettability of the gel electrolyte on the electrode surface have produced a device with an improved rate capability and cyclability that undergoes hardly any changes in C sp , cell , E real , and P real of the cell when folded. Graphical abstract Image 1 Highlights • A novel PIL/IL-GPE with remarkable adhesive characteristics has been developed. • The performance of the PIL/IL-GPE was tested in a flexible supercapacitor (SC). • PIL/IL GPE supercapacitor was studied using galvanostatic synchronous measurements. • The PIL/IL GPE led to a device with an improved rate capability and cyclability. • The SC showed no significant changes in C sp , E real and P real when the cell was folded. [ABSTRACT FROM AUTHOR]

Abstract The electrolyte system is a critical component in a dye-sensitized solar cell (DSSC). A starch-based gel polymer electrolyte (GPE) is described herein as a potential quasi-solid-state electrolyte system for DSSC. Potato starch was modified by grafting 1-glycidyl-3-methylimidazolium chloride (GMIC) ionic liquid onto the polysaccharide chain to afford a cationic starch (CS) as confirmed by elemental analysis (nitrogen content = 1.33%), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Despite its low degree of substitution (0.084), the resulting properties of the new cationic starch such as its coarse yellowish brown coloration, high-water solubility, flaky morphology, higher thermal stability, and higher gelatinization temperature differentiate it distinctly from the raw starch. In DMSO solvent, the cationic starch (CS) forms a gel and addition of GMIC ionic liquid (CS:GMIC ratio 1:3) as plasticizer afforded a gel polymer electrolyte (GPE) system after doping with the KI/I 2 (70 wt%) redox couple. Electrochemical impedance spectroscopy revealed high conductivity and efficient ion migration. The optimized CS-GPE was incorporated in DSSC as quasi-solid-state electrolyte system affording 0.514% efficiency. Despite its low performance against the liquid electrolyte control, it exhibited relative stability due to its good filling contact between the electrodes. [ABSTRACT FROM AUTHOR]

Abstract An exceptional approach of appending tris(1,10-phenanthroline)cobalt(II)/(III)bis/tris(hexafluorophosphate) and synthesized tetramethyl benzidine-based thiourea derivatives as novel additives with hydroxypropyl cellulose are used to construct a gel polymer electrolyte for DSSC. The thiourea derivatives are synthesized using the cost-effective method. The synthesized derivatives are confirmed by 1H, 13C NMR and mass spectroscopy. The conductivity, surface and redox potential of thiourea derivatives doped Co2+/Co3+ redox electrolytes are scrutinized by impedance spectra, FTIR, UV, XRD. A density functional theory method with full geometry optimization is used to elucidate the adsorption of the symmetrical thiocarbamides on TiO 2 (101) surface progressing with electron donating/accepting groups. All the organic compounds display a negative shift on the TiO 2 Fermi level simultaneously by adsorption and rebutted as an escalated additive in stable Co(II/III)phen redox electrolyte of the dye-sensitized TiO 2 solar cell. This impulse effect influences the sorbate dipole moment component normal to TiO 2 surface plane; further, the stable redox mediator and hydroxypropyl cellulose deliver a good performance in a dye-sensitized solar cell. The newly synthesized thiourea derivatives doped Co2+/Co3+ with hydroxypropyl cellulose reports high solar to electric conversion, particularly 1,1'-(3,3′,5,5′-tetramethyl-[1,1′-biphenyl]-4,4′-diyl)bis(3-(3,4,5-trimethoxy phenyl)thiourea) (additive-6) doped redox electrolyte shows an outstanding efficiency (ŋ) of 9.1% under the sunlight irradiation of about 70 mW/cm 2 . Graphical abstract Image 1 Highlights • Introduction of coherent hydroxypropyl cellulose for gel polymer electrolyte. • Simple and cost-effective synthesis of thiourea. • Thioureas behave as a systematic additive on TiO 2 (101). • Gel polymer electrolyte facilitates enhanced electrical conductivity. • The gel polymer electrolyte with thiourea based DSSC shows good performance and high photovoltaic conversion 9.1%. [ABSTRACT FROM AUTHOR]

• Gel polymer electrolytes with high ionic conductivity and good stability are obtained by adding cellulose derivative to poly acrylamide electrolyte. • The electrochromic device using the gel polymer electrolyte exhibits fast response and good cycling stability. • The good electrochromic properties are attributed to the existence of large number of hydrogen bonds between poly acrylamide and cellulose derivative. Cellulose is one of the most widely distributed and abundant natural polymer material. Hypromellose (HPMC), a cellulose derivative, has received much attention in recent years in the field of electrolytes because of its biodegradability, high transparency, excellent water solubility and biocompatibility. In this work, poly acrylamide (PAM)-based hydrogel electrolytes with high ionic conductivity (5.3 × 10−2 S cm−1) and high transmittance (95.8% at 672 nm) were prepared by thermocuring AM monomer containing a certain amount of HPMC. We assembled an electrochromic device (ECD) based on this gel polymer electrolyte (GPE) with Prussian blue (PB) film and WO 3 · x H 2 O film. The ECD enables color switching between colorless and blue states. The optical modulation at 672 nm is 73.2% and the coloration efficiency is 154.7 cm2⋅C−1. The coloration time and bleaching time are 2.5 and 3.1 s, respectively. In addition, the optical modulation of the ECD remains 93.7% of its initial value after 1,000 cycles, demonstrating a good cycling stability of the ECD, which should be attributed to the existence of large number of hydrogen bonds between PAM and HPMC. [ABSTRACT FROM AUTHOR]

The quest for safe and high-performance polymer electrolytes in lithium-ion batteries (LIBs) has led researchers to explore protic ionic liquids (PILs) as potential candidates to be entrapped in polymer matrices. In this context, we present an investigation into solid polymeric systems based on poly(methyl methacrylate) (PMMA) as a host for PILs, featuring 1,8-diazabicyclo-[5,4,0]-undec-7-ene (DBU) cation paired with three different anions: bis(trifluoromethanesulfonyl)imide (TFSI−), trifluoromethanesulfonate (TFO−), and (trifluoromethanesulfonyl-nonafluorobutylsulfonyl)imide (IM14−). Additionally, we explore the lithium-doped IM14-gel-like system to broaden our understanding of these intriguing materials. Through comprehensive thermal analysis, solid-state NMR, and diffusion NMR techniques, we delve into the interactions and structural features of these binary and ternary polymeric systems. Our investigation reveals unique dynamics and ion interactions within the PMMA matrix, shedding light on the potential of these materials for advanced energy storage technologies. Particularly, we highlight the distinctive features of DBUH-IM14 and its specific interaction with the polymeric matrix and the lithium ions, underscoring its significance in advancing safer and more efficient energy storage devices. [ABSTRACT FROM AUTHOR]

Abstract A compositive synthesis of gel polymer electrolytes by blending poly(propylene carbonate) (PPC) into poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) as a polymer host is proposed. The blending polymer is produced by a facile solution casting method and ester groups of PPC are successful introduced into PVDF-HFP. The gel polymer electrolyte displays an excellent ion conductivity of 1.18 × 10−3 S cm−1, broad electrochemical window up to 4.8 V (vs. Li/Li+) and outstanding electrochemical stability within rechargeable lithium batteries at room temperature. The improvement of ion conductivity is attributed to the decrease of polymer crystallizability and the increase of micro pores. The strategy of blending is promising for the modification of PVDF-HFP electrolyte and foreground application in next-generation solid energy conversion devices. [ABSTRACT FROM AUTHOR]

Abstract In this work, a new porous cross-linked membrane is prepared and used as the separator for rechargeable lithium-ion batteries. The inorganic zinc oxide nanoparticle (nano-ZnO) was added as a pore-forming agent and filler to the preparation process of membranes composed of poly(vinylidene fluoride- co -hexafluoropropylene) (PVdF-HFP) and a cross-linked polymer by the copolymerization from poly(ethylene glycol methyl ether methacrylate) (PEGMEMA), methyl methacrylate (MMA) and octavinyl-T8-silsesquioxane (OVPOSS). The prepared membrane was firstly swollen by propylene carbonate (PC) and nano-ZnO was then eluted by hydrochloric acid to form the microporous structure. The effects of particle size and additive amount of nano-ZnO on the mechanical and electrochemical properties of microporous membranes were studied. SEM analysis showed that 30 nm nano-ZnO was the most suitable diameter for forming microporous structure. It is generally considered that the ionic conductivity is inversely correlated with the mechanical strength of separator. In our research, we have found that 18% addition of nano-ZnO was the most appropriate amount for the preparation of a microporous membrane (CRZ18) with an ionic conductivity of 1.4 mS cm−1 and a tensile strength of 10.7 MPa. Meanwhile, the LiFePO 4 /Li half-cell assembled with the CRZ18 membrane as a separator exhibited the best C-rate capacity and cycle charge-discharge performance, indicating that the CRZ18 membrane would be a kind of promising separator for the high-performance lithium-ion batteries. Highlights • A new porous membrane is prepared using nano-ZnO as the additive and pore-forming agent. • The additive shows favorable pore-forming properties and the resultant membrane maintains considerable mechanical strength. • Good thermal stability and mechanical strength contribute to higher battery safety. • Half-cell assembled with membrane shows stable cycling and good rate performance. [ABSTRACT FROM AUTHOR]

Polymer gel electrolytes for electric double layer capacitors (EDLC), also known as supercapacitors, represent a safe and low-cost alternative to liquid electrolytes. This study shows that EDLCs with polymer gel electrolytes may accomplish gravimetric capacitances comparable to or even higher than those of EDLCs with the same carbon electrodes and the respective ions in aqueous electrolyte. One of the most important parameters in this context is the effective electrode/electrolyte interface. This can be improved by using a suitable electrode and assembling method for the polymer electrolyte component. As polymer gel electrolytes we investigated polyvinyl alcohol (PVA) with either phosphoric or sulfuric acid as well as PVA and sulfuric acid with hydroxyethyl-cellulose as an additive in combination with porous carbon (xerogel) electrodes with different meso/macrostructures. The gravimetric capacitances determined for EDLCs with the sulfuric PVA electrolyte were considerable higher than those of EDLCs using phosphoric acid. Furthermore, the results of our study indicate a clear influence of the electrodes pore structure and the applied assembling method on the specific capacitance. The processing method providing the best contact between polymer electrolyte and electrode yields EDLCs with a gravimetric capacitance comparable to or even higher than that of EDLCs with liquid H 2 SO 4 . The experimental findings strongly suggest that micropores in the interconnected carbon backbone of the electrode - including such in regions that are not in direct contact with the polymer gel phase - are saturated with electrolyte and contribute to the capacitance. [ABSTRACT FROM AUTHOR]

Polymer gel electrolyte is defined as a combination of copolymer, suitable electrolyte and high boiling point solvents, demonstrating great potential in the fields of solid electrolytes in terms of good ionic conductivity, tunable mechanical properties and suitable viscosity. In this report, we successfully incorporated polymer gel electrolyte into electrochromic mixtures (consisting of hydroxyalkyl viologens and electron mediators hydroquinone (HQ) or ferrocene (Fc)) to fabricate single-layer all-in-one electrochromic devices (ECD). Although simplifying structure of the ECD, the device exhibited low driving voltages (0.9 V for Fc based ECD, 1.5 V for HQ based ECD), high optical contrast (up to 82%) and satisfactory coloration efficiency (>240 cm 2 C − 1 ) as we expected. Flexible single-layer ECD based on ITO/PET was also obtained by the simple fabrication process. On the whole, the device can be presented as a proof-of-concept in the fields of low-cost and flexible smart windows. [ABSTRACT FROM AUTHOR]

• (3-Aminopropyl) triethoxysilane with 1,4-Butane sultone to obtain zwitterionic silane (ZSi). • ZSi is grafted onto nano-hydroxyapatite (nHA) to obtain nHA-ZSi. • nHA-ZSi reduces the crystallization of the polymer matrix due to filler effect. • The specific capacitance increases with the addition of nHA-ZSi; reaches the maximum at 20%. In this study, we intend studying the role of nano-hydroxyapatite bearing zwitterion within carboxylated chitosan hydrogel electrolyte in improving supercapacitor performance. First, we carry out the ring-opening addition of (3-Aminopropyl) triethoxysilane with 1,4-Butane sultone to obtain zwitterionic silane (ZSi). Then, ZSi is grafted onto nano-hydroxyapatite (nHA) by condensation process to obtain nano-hydroxyapatite grafted zwitterionic silane (nHA-ZSi). The successful synthesis of nHA-ZSi is confirmed by Fourier transform infrared spectroscopy and 13C Nuclear magnetic resonance. Differential scanning calorimetry shows that the incorporation of nHA-ZSi reduces the crystallization of the polymer matrix due to filler effect. Afterwards, nHA-ZSi with 5%, 10%, 20%, 30% are mixed with carboxylated chitosan (CCS) to obtain composite films (CCS/nHA-ZSi). The stress-strain curves of CCS/nHA-ZSi are characterized by tensile testing. Ionic conductivities of hydrogel electrolytes are estimated by soaking CCS/nHA-ZSi in 1 M Na 2 SO 4 via electrochemical impedance. Furthermore, CCS/nHA-ZSi hydrogel electrolytes are assembled with symmetric carbon electrode for electrochemical tests, including cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance. The specific capacitance increases with the addition of nHA-ZSi; reaches the maximum at 20%; and then decreases due to aggregation. After 5000 cycles, CCS/20% nHA-ZSi supercapacitor has 98% capacitance retention at 6 mA/cm2. This study demonstrates that nano-hydroxyapatite bearing zwitterion is a beneficial additive for both mechanical strength and ionic conductivity in hydrogel electrolytes. [Display omitted] [ABSTRACT FROM AUTHOR]

Developing electrolytes qualified for high-voltage (>4 V vs Li/Li+) conditions is of great significance for high-energy density Li-metal batteries (LMBs). Carbonate-based electrolytes possess high oxidation stability, whereas the uneven Li deposition, low Coulombic efficiency (CE) and poor anodic stability of such electrolytes severely impede the practical application in high-voltage LMBs. Herein, a 1.8 M lithium bis(trifluoromethanesulphonyl)imide (LiTFSI)-carbonate electrolyte with high compatibility with both Li anode and high-voltage cathode is designed. LiNO 3 is introduced into the electrolyte as an additive with the assistance of CuF 2 cosolvent, which efficiently enables robust and conductive interfaces at both anode and cathode sides. As a consequence, an average CE of 98.0% is achieved for Li||Cu half-cell at 1 mA cm−2. Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 full cell fabricated with cathode areal capacity of 2.4 mAh cm−2 and 5× excess Li achieves a high capacity retention of 80.7% after 200 cycles with cut-off voltage of 4.3 V. This work provides a facile and effective approach to improve the application of carbonate-based electrolytes in high-voltage LMBs. [ABSTRACT FROM AUTHOR]

• Single step methacrylation of gelatine from the fishing industry waste • One pot photoreticulation of methacrylated gelatine with liquid electrolyte • High ionic conductivity of 2.51 mS cm−1 and lithium transference number of 0.54 • More than 100 cycles at 0.1 mA cm−2, under constant O 2 flow, at room temperature • Reduced solvent degradation thanks to the bio-renewable polymer The lithium-oxygen battery has attracted wide interest thanks to its very high theoretical energy density, and as such it is considered by many as a valid battery of the future candidate. However, the challenges in its practical application are many, such as liquid electrolyte evaporation in semi-open systems, as well as solvents instability in a highly oxidizing environment. In this work, we propose to use gelatin, from cold water fish skin, a waste from the fishing industry, to prepare an efficient gel electrolyte for future Li-O 2 battery applications. After a single step methacrylation in water, methacrylated gelatine is directly cross-linked in presence of liquid electrolyte through UV- initiated radical polymerization. The obtained gel polymer electrolytes present good thermal and mechanical properties, good electrochemical stability against Li metal and ionic conductivities as high as 2.51 mS cm−1 at room temperature. the Li-O 2 cells assembled with this bio-renewable gel polymer electrolytes were able to perform more than 100 cycles at 0.1 mA cm−2, under constant O 2 flow, at room temperature and at a fixed capacity of 0.2 mAh cm−2. Cathodes post- mortem analysis confirmed that the cross-linked gelatin matrix was able to slow down solvent degradation and therefore enhance the cell reversibility. [ABSTRACT FROM AUTHOR]

• Improving the cycle stability and colouring efficiency of vanadium-based electrochromic films. • Developing a self-healing gel electrolyte suitable for electrochromic devices, which solves the problem of difficult encapsulation and easy leakage of devices. • Maximizing the use of the discoloration area of the film and realizing the diversity of discoloration modes and functions. Electrochromic materials have garnered significant interest owing to their eco-friendliness, energy efficiency, and ease of use. Among these materials, vanadium-based compounds are regarded as highly promising; however, they are plagued by issues such as ion channel collapse, capacity loss, and inadequate cycling stability when employed in aqueous solutions. The present study involves the compounding of KV 3 O 8 ·0·75H 2 O (KVO) into a network composed of linear methylcellulose, leading to the development of a self-supporting cellulose composite KVO electrochromic film. Specifically, the doping of K was found to disrupt the preferential orientation of the V 2 O 5 (001) crystal plane and to widen the interplanar spacing to 6.9 Å. Furthermore, Cellulose was discovered to remarkably increase the viscosity of the solute (6 times) and to undertake the function of a "reinforcing agent". The methylcellulose composite KVO film's electrochromic properties were then investigated in a 1 mol L −1 LiClO 4 non-aqueous electrolyte. Consequently, the film was able to switch between green-yellow and orange-red, and it was also capable of conserving more than 67% of its charge capacity after 2000 cycles. More importantly, flexible electrochromic devices were assembled from KVO/MC films. A self-healing LiClO 4 /PC (LOC)-based gel electrolyte composed of Ethene, 1‑chloro‑1,2,2‑trifluoro-, polymer with 1,1‑difluoroethene (P(CTFE‑VDF)) and Li+ electrolyte was developed, which was highly compatible with the device. The device possessed a high color efficiency of 78.8 cm2 C −1, and achieved fast response (≤5.6 s) and long service life (>77% of the charge capacity and 70% of the optical contrast after 10,000 cycles). This design presents considerable potential for the fabrication of large area (12 × 15 cm2) flexible devices. The K ions intercalated KV 3 O 8 ·0·75H 2 O (KVO) sol is compounded with cellulose, which has a large interlayer spacing, showing a state of layered V 3 O 8 and strip cellulose interspersed and evenly distributed. The electrochromic film prepared by this method unfolds excellent electrochemical and optical properties. Gel-state LOC electrolyte is further applied to the lateral transmission flexible electrochromic device (TFECD) and lateral-vertical complementary reflection flexible electrochromic device (RFECD). They show the versatility and abundant operability. [Display omitted] [ABSTRACT FROM AUTHOR]

The use of biopolymers for the preparation of gel polymer electrolytes (GPEs) to construct high-performance energy storage devices contributes to the development of new sustainable materials. Herein, an alginate-based gel electrolyte was used in the construction of a supercapacitor, to aim for an environmentally friendly device. Alginate was crosslinked with calcium ions (ALG-Ca2+) resulting in gels with good mechanical properties and ionic conductivity, suitable for their use as electrolyte and separator for a symmetric supercapacitor, assembled in a coin cell architecture and using polypyrrole as the electrode. The device presented a specific cell capacitance of 39.5 F g-1 at 0.2 A g −1, and durability of 70.9% after 2000 galvanostatic charge-discharge (GCD) cycles. Based on these properties, three devices were connected in series and demonstrated to be able to light up a 3.0 V LED. The influence of temperature on supercapacitor performance was verified by varying the temperature from 10 to 60 °C and evaluating the characteristic cyclic voltammograms and GCD profiles. The devices were able to operate in the temperature range of 10 to 60 °C, with no loss of their capacity properties. [Display omitted] [ABSTRACT FROM AUTHOR]

• A series of FEC modified gel polymer electrolytes have been successfully prepared by one-step in-situ polymerization. • By adjusting the FEC content, a stable NaF-rich interface is formed between the electrolyte and the electrode. • Matching Na 3 V 2 (PO 4) 3 cathode delivers excellent cycling stability, with a capacity retention of 95.31% over 1000 cycles at 5 c. Sodium metal batteries (SMBs) are considered feasible candidate for large-scale energy systems. However, complicated reactions between the electrode and electrolyte in liquid electrolyte system lead to poor performance and significant safety issues. Therefore, constructing stable electrode-electrolyte interface is necessary to enhance the comprehensive performance of cells. Utilizing gel polymer electrolytes (GPEs) by in-situ polymerization and moderate additive can effectively address these problems. Herein, a series of fluoroethylene carbonate (FEC) modified GPEs have been successfully prepared by one-step in-situ polymerization, in which trimethylolpropane trimethyl acrylate (TMPTMA) and 1,6-hexanediol diacrylate (HDDA) were used as polymer monomers. As a result, the as-optimized electrolyte, THDP-FEC-2%, exhibited high ionic conductivity (3.77 × 10−3 S cm−1) at 25 °C, high Na+ migration number (0.41), and broad electrochemical window (4.6 V). Encouragingly, the NVP|THDP-FEC-2%|Na cell even exhibited ultra-long cycling stability at high rate (95.31% capacity retention at 5C after 1000 cycles). Such excellent electrochemical performances are attributed to the successful establishment of uniform and dense NaF-rich solid electrolyte interface protection layer. This work is expected to offer interface soft protection layer tuned strategy to construct the ideal interface for high-performance SMBs. [Display omitted] [ABSTRACT FROM AUTHOR]

Many severe problems of lithium (Li) metal anode during cyclings, such as dendritic formation, dead Li, volume expansion, and safety issues, hinder practical applications of Li metal batteries (LMB). Ensuring performance stability by a gel polymer electrolyte (GPE), combined with strengthening the Li surface, is considered an effective strategy to solve the problems of the LMB. Herein, a composite of titanium dioxide (TiO 2) with multiwall carbon nanotube (MWCNT) acted as artificial solid electrolyte interphase, effectively controlling the Li electrodeposition process and sustaining the structural integrity of the anode. The characteristics of the composite suspension elucidate the vital role of citric acid in the TiO 2 surface functionalization, thereby creating effective adsorption with MWCNT, which directly built a new composite. The cycle performance of the TiO 2 /MWCNT/Li anode in the GPE-based LMB is evaluated with a high energy density electrode that stably maintains over 200 cycles. The cross-sectional image of the advanced anode shows the ability to rebuild a strong and durable anode structure after many stripping/platting cycles. The advanced anode applied on a thin Li (70 µm) and a medium capacity cathode shows efficiency based on over 580 cycles. [Display omitted] [ABSTRACT FROM AUTHOR]

This work reports the enhanced mobility of ions in ionic liquid (IL)-based gel polymer electrolytes (GPEs) with the incorporation of Al 2 O 3 nanofibers. A combination of PVDF-HFP, EMIMTFSI and LiTFSI with 3 wt% Al 2 O 3 nanofibers has been prepared through solution casting technique. The room temperature ionic conductivity of PVDF-HFP: ILs electrolyte (45:55, weight ratio of 0.82) (GPE) is found to be 2.7 × 10−5 S cm−1, which increases up to 7.8 × 10−5 S cm−1 in Al 2 O 3 containing GPE (Al-GPE). Pulsed field gradient (PFG) NMR results validate the increased ionic conductivity observed in Al-GPE. We found that the diffusivity of Li+, TFSI− and EMIM+ increases when Al 2 O 3 nanofibers are well-distributed in the GPE matrix. The surface morphology and the amorphicity of GPEs are examined through SEM and XRD analyses. Lastly, the local structure of Al 2 O 3 fibers and the molecular-level interactions of ions with polymer, and their effect on the diffusivity of ions are established through solid-state NMR detecting 27Al, 1H, 13C, 19F nuclei including 2D 13C{1H} HETCOR NMR experiments. The 13C DPMAS and CPMAS experiments highlight the dynamic heterogeneity associated with the ions that are embedded in the rigid and the mobile phase of GPEs. While some of the ionic species strongly interact with polymer chains in the rigid environment, the majority of them reside in the mobile phase and contribute to the overall increased conductivity. Most importantly, Al 2 O 3 nanofibers significantly affect the dynamics of ionic species that are present in the mobile phase between the polymer chains. [Display omitted] [ABSTRACT FROM AUTHOR]

• IL-PTZ is applied to the additive of gel polymer electrolyte for improving the electrolyte properties, stability against Li, and redox activity of Li-air batteries. • IL-PTZ@GPE shows high ionic conductivity and mechanical stability. • Li anode surface is stabilized by IL-PTZ@GPE, resulting in stable deposition of Li and suppression of dendrite formation. • Li-air cell with IL-PTZ@GPE exhibits superior capacity of 4685 mAh g − 1 and cyclability. Lithium-air batteries have the highest theoretical energy density among the rechargeable batteries. However, Li dendrite growth and the limited decomposition of discharge product, Li 2 O 2 , restrict the battery performances. In our recent study, we synthesized and utilized ammonium ionic liquid-functionalized phenothiazine (IL-PTZ) as a new redox mediator with stability against lithium to deal with these issues. Replacing liquid electrolyte to gel polymer electrolyte (GPE) is also one promising approach to enhance electrochemical performance. GPE with functional additive have been studied for improving flexibility, ionic conductivity, and chemical stability. In this study, we introduce IL-PTZ as an additive for the superior mechanical property and ionic conductivity of GPE. The elongation force of the GPE with IL-PTZ (IL-PTZ@GPE) was enhanced two times higher than that of GPE without the additive. The ionic conductivity also increased up to 1.53 × 10−3 and 4.76 × 10−3 S cm−1 at 20 and 80 °C, respectively. Furthermore, IL-PTZ molecules suppressed Li dendrite growth on the Li anode and accelerated oxygen evolution/reduction reactions on the cathode surface. IL-PTZ with only small amount of 0.1 M can act as multi-functional additive, resulting in the synergistic improvements mentioned above. As a result, Li-air cell with IL-PTZ shows superior electrochemical performances with the initial discharge capacity of 4685 mAh g − 1 and 4 times longer cyclability than the cell without additive. [Display omitted] [ABSTRACT FROM AUTHOR]

Polymer gel electrolytes having super catalytic behaviors and robust Pt-free counter electrodes (CEs) are promising for high-efficiency and cost-effective quasi-solid-state dye-sensitized solar cells (DSSCs). We present here the molecular design of polyaniline (polypyrrole)-graphene complex for conducting gel electrolytes and CEs, aiming at reducing their charge-transfer resistance and enhancing catalytic activity. The quasi-solid-stated DSSCs tailored with polyaniline-carbon nanotube and polypyrrole-carbon nanotube complexes yield maximized power conversion efficiencies of 8.23% and 7.69%, respectively. Arising from good encapsulation of three-dimension gel matrix, the photovoltaics are featured with relatively good long-term stability over 15 days. The high-efficiency and reasonable durability make so-called conducting gel electrolytes and Pt-free CEs promising in enhancing comprehensive properties of quasi-solid-state DSSC platforms. [ABSTRACT FROM AUTHOR]

Dye sensitized solar cells (DSSCs) have received significant attention due to their low production cost and easy fabrication process. However, the leakage and volatilization of the liquid organic solvent in the liquid electrolyte affect the long term stability of DSSCs. Therefore, in this present work, to improve the durability of DSSCs, polymethyl methaacrylate (PMMA) based polymer gel electrolyte (PGE) with different weight percent of carbon black (CB) was studied to replace the conventional liquid electrolyte. CB was used to improve the ionic conductivity of the PGE. DSSCs fabricated with the prepared PGEs exhibit very good long term stability in comparison to liquid electrolyte. The optimized DSSC with 0.57 weight percentage of CB in PMMA polymer matrix exhibits the highest photo-conversion efficiency of 5.52 ± 0.03% with short circuit current density (J sc ) value of 12.43 ± 0.04 mA cm −2 , open circuit voltage (V oc ) value of 766.02 ± 0.52 mV and fill factor (FF) value of 58.01 ± 0.02%. A significant enhancement of V oc is observed with the employment of the PGE. The impact of the PGE in the enhancement of V oc was studied by analyzing the charge transfer kinetics data at the interface of the photoanode and the PGE. Furthermore, the study of long term stability shows that after 1000 h of testing the optimized DSSC (PGE(0.57)) retains the J sc value at 83% of the initial performance exhibiting very significant long term stability in comparison to the DSSC fabricated with liquid electrolyte. [ABSTRACT FROM AUTHOR]

The massive use of lithium batteries in industries, such as automotive and electrical network accumulation, requires the development of safer electrolytes, economic and possibly made from renewable resources using eco-friendly processes. In this work, we reported the synthesis and the physico-chemical and functional characterization of a polymer gel electrolyte (GPE) based on a skeleton of polyhydroxyalkanoate obtained from biomass by means of an easy and environmentally friendly chemical process. The GPE has an ionic conductivity of 0.8 mS cm −1 at room temperature, is thermally stable up to over 100 °C and is not flammable. The electrochemical stability window is higher than 5 V. The cell Li/GPE/LiFePO 4 shows specific capacity of 100 mAhg −1 at 3C with 100% coulombic efficiency. These results demonstrate that the GPE based on polyhydroxyalkanoate is very promising for use in lithium batteries of high power density. [ABSTRACT FROM AUTHOR]

To investigate the influence of anion structure on physical properties of electrolytes we used five different anions, namely (FSO 2 ) 2 N (FSI, FSA), (CN) 2 N (DCA), (CF 3 SO 2 ) 2 N (TFSI, TFSA), CF 3 SO 3 (TfO) and (CF 3 SO 2 )N(CN) (TFSAM), and investigated them in a series of polyelectrolytes, ionic liquid (IL)/Li salt mixtures and in ternary ion gels (poly(ionic liquid)/ionic liquid/Li salt), respectively. Both the poly(ionic liquid) (PIL) poly(diallyldimethylammonium) (PDADMA) and the ILs employed in the study have the same pyrrolidinium anion. To isolate solely the effect of the anion a common chloride precursor PIL was used to maintain constant the average degree of polymerization ( DP n ) and chain dispersity. The systems were analyzed in terms of ionic conductivity, electrochemical stability vs Li + /Li, ion diffusion (multinuclear Pulsed Field Gradient NMR) and local lithium ion dynamics ( 7 Li spin lattice relaxation rates). Concerning optimization of any of these parameters, different orders of the anion series are obtained and discussed in terms of structural aspects and ion coordination. In particular, the coordination strength of the –CN group to the lithium ion is higher than the coordination strength of the oxygens of the –SO 2 CF 3 fragment. As a result the lithium ion in the TFSAM samples is primarily coordinated by the –CN group. Detailed structure/property relationship analysis demonstrated that for those applications of ion gels (capacitors, sensors, etc.) where a high conductivity is a primary demand, while the electrochemical stability is not essential, the FSI anion will be the best choice. However, for energy storage systems such as Li metal batteries preferably TFSI but also TFSAM anions will represent the best compromise of relevant parameters. [ABSTRACT FROM AUTHOR]

Due to their high operating voltages, energy densities and safety performance, all solid-state Li metal batteries (ASSLMB) share a bright application prospect. However, the poor ion transport and contact issue at cathode electrolyte interphase (CEI) will easily lead to severe capacity degradation at high operating voltages, which remained as the bottleneck problem for ASSLMB. In this work, a CEI layer consisting of LiF and Li x BO y F z was in-situly constructed through the synergistic decomposition of DFOB− and TFSI− from ionic liquids. At high operating voltages, this stable and thin CEI layer could not only protect the ionic liquid-based electrolytes by suppressing the polarizations and side reactions on the cathodic surfaces, but also facilitate the transfer of interfacial lithium ions. When tested at 0.1C and 60 °C with a high cut-off voltage of 4.5 V, this ASSLMB possessed an initial specific capacity of 190.7 mA h g −1 and an 80% capacity retention after 100 cycles. Our findings provide a promising approach to realize ionic liquid-based electrolytes in high-voltage ASSLMBs. [ABSTRACT FROM AUTHOR]

The alkaline gel polymer electrolyte, polyvinyl alcohol (PVA)-sodium polyacrylate (PANa)-aquatic colloidal graphene (ACG)-KI (PVA-PANa-ACG-KI), was prepared by solution casting method. Fourier transform infrared spectrometer (FTIR), scanning electron microscope (SEM), electrochemical impedance spectra (EIS), cyclic voltammetry (CV) and water retention were used to study the performance of PVA-PANa-ACG-KI gel polymer electrolyte. The results show that the ionic conductivity of PVA-PANa-ACG-KI is 283.7 mS·cm–1, the electrochemical stability window is 2.6 V, and the water retention is 73.4%. The discharge capacity of the flexible zinc air batteries (ZABs) with PVA-PANa-ACG-KI gel polymer electrolyte is 803.56 mAh g Zn –1, the continuous charge-discharge time is 62 h, the cycle efficiency is 74.2%, and the self-discharge rate is 0.36%. After the charge-discharge cycle, the GPE is recycled and put into use again, which effectively reduces the cost. Finally, the advantages and prospects of flexible ZABs are demonstrated, and the feasibility of flexible ZABs is proved. [Display omitted] [ABSTRACT FROM AUTHOR]

Blending two different polymers through a physical blending is a wise alternative to create a new polymer with desired properties showing a synergistic effect of the individual polymers. In this work, polyacrylonitrile (PAN) and poly (1-vinylpyrrolidone-co-vinyl acetate) P(VP-co-VAc) were blended in a fixed amount of binary organic solvent of ethylene carbonate and propylene carbonate. The weight ratios were varied to 30:70, 50:50 and 70:30 wt%, respectively. Polymer electrolytes in a gel and solid form are safer than liquid ones. Thus 50:50PP and 70:30PP samples were selected and incorporated with iodide/triiodide redox mediators such as sodium iodide salt, 1-methyl-3-propylimidazolium iodide (MPII) ionic liquid and iodine for dye-sensitized solar cells (DSSC) application. Polymer electrolytes containing 50 wt.% of both PAN and P(VP-co-VAc) with iodide/triiodide redox mediator (50:50PP-IL) has achieved maximum ionic conductivity, short-circuit (JSC) current and power conversion efficiency (PCE, η) of 6.10 × 10−3 S cm−1, 11.1 mA cm−1 and 5.35%, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

The aim of this work is to improve the electrochemical performance of lithium-ion batteries by developing an inorganic-polymer gel electrolyte and anode electrode, which both use helical mesoporous silica nanofibers (HMSFs) as the skeletons. Based on this design, the electrolyte/anode interphase is naturally integrated, which consequently show excellent properties in electrochemical measurements. The HMSFs incorporated into P(VDF-HFP) matrix to form the electrolyte membranes (named as NPCGE) exhibit high thermal stability (up to 372 ℃), wide electrochemical window (5.30 V), and high room temperature ionic conductivity (1.2 × 10−3 S cm−1). Meanwhile, helical mesoporous silica/Fe-N-doped carbon composite nanofibers (HMSFs@Fe-N-C) was fabricated by carbonizing Fe-adsorbed resin/silica/gel composites and then acted as the anode material in lithium-ion batteries (LIBs). The assembled HMSFs@Fe-N-C|NPCGE|Li cell show a high specific capacity around 1290 mAh g −1 over 500 cycles at a current density of 0.3 A g −1 and excellent rate performance, which was not only ascribed to the special composition and nanostructure of the electrolyte and electrode materials, but also to the benign interfacial contacts. [Display omitted] [ABSTRACT FROM AUTHOR]

As an alternative to conventional liquid electrolytes, self-healing gel polymer electrolytes (SHGPEs) can effectively increase the safety performance and lifetime of lithium metal batteries (LMBs). However, the poor mechanical properties and unfavorable ionic conductivity limit its further use. Herein, based on a simple in situ polymerization strategy, a novel dual-network structure self-healing gel polymer electrolyte (DN-SHGPE) with mechanical strength and self-healing properties is designed and prepared. The brush copolymer PEG-UPy contains a large amount of dynamic urethane-pyrimidine (UPy) dimer, acting as the first network, which gives GPE great self-healing ability and increases the safety and cycle lifetime of lithium batteries. The second network is cross-linked polyethylene glycol diacrylate (PEGDA), which ensures the dimensional stability and mechanical qualities of GPE. In comparison to the unmodified polymer electrolyte PEG-UPy, DN-SHGPE exhibits better ionic conductivity, excellent mechanical property, and good thermal stability, as well as good interaction stability with Li metal anode. When assembled with LiFePO 4 and lithium metal electrodes, the resultant cells show a high reversible specific capacity and good rate capability. [ABSTRACT FROM AUTHOR]

• New sustainable POM-based electrolyte formulations for aqueous symmetric RFBs. • Complete physicochemical and electrochemical characterization of RFBs electrolytes. • Insight to improve RFB performance by composition optimization of the electrolyte. Sustainability and safety of Redox Flow Batteries (RFBs) are some of the limitations that hinder the further implementation of this technology. To overcome the disadvantages of conventional RFBs, new electrolyte formulations are being proposed. Herein we report on two cobalt(II)-containing Keggin-type polyoxometalates (POMs) working as electroactive species. These are the plenary [α-CoW 12 O 40 ]6− (CoW 12) anion and the cobalt(II)-monosubstituted [α-Co(H 2 O)SiW 11 O 39 ]6− (CoSiW 11) tungstosilicate. During the battery performance, cobalt-containing POMs play the role of both positive and negative electrolyte, because the ability of Co (CoIIWVI/CoIIIWVI) and W (CoIIWVI/CoIIWV) centres to be oxidized and reduced, respectively. These redox processes are separated by 1.7 V (CoW 12) and 1.9 V (CoSiW 11) thus, both POMs supply with a suitable operational voltage for RFBs. The reversibility of the reactions was examined by a kinetic study. Among the formulations tested, those accomplished in aqueous 1 M HAc/LiAc and 1 M LiAc revealed high stability while operating under mild pH conditions. Moreover, the nature of the selected supporting electrolytes (SEs) avoids the occurrence of gassing side reactions. In addition, the physicochemical characterization of the electrolytes showed high conductivity (ca. 60 mS cm−1) and low viscosity (ca. 1.4 mPa s) for highly concentrated electrolytes (up to 120 mM). Therefore, the developed electrolytes exhibit promising properties for their direct incorporation in RFBs, including high energy density (21.86 and 24.44 W h L−1 for CoW 12 and CoSiW 11 respectively) and enhanced safety. [ABSTRACT FROM AUTHOR]

• A IL-assisted quasi-solid-state polymer electrolyte was fabricated for lithium metal batteries. • The released IL under pressure serves as in-situ electrode surface wetter and solid/electrolyte interphase modifier. • The IL-assisted QSPE holds favorable overall properties and endows superior room-temperature performance for LMBs. Solid-state electrolytes are emerging as a promising approach to improve the safety and cycle life of lithium metal batteries (LMBs). However, low ionic conductivity, narrow potential window and deficient interfacial contact with the electrodes greatly hinder their practical applications. Herein, an ionic liquid (IL)-assisted quasi-solid-state polymer electrolyte (QSPE) by incorporating functional Pyr 14 TFSI into the PVDF matrix is developed. Profitted from the inherent interaction between the IL and polymer, the optimizedly-designed QSPE holds favorable overall properties including ionic conductivity, electrochemical window, Li ion transfer number and mechanical strength. Moreover, the SEM, XPS and EIS analyses reveal that the released IL under external pressure during cell assembly serves as a in-situ electrode surface wetting agent to promote ionic transport and charge transfer, as well as a solid/electrolyte interphase modifier to mitigate the electrolyte degradation and homogenize Li deposition. Consequently, the assembled quasi-solid-state LMBs demonstrate superior cycle and rate capability at room temperature. An ionic liquid (IL)-assisted quasi-solid-state polymer electrolyte by incorporating the functional Pyr 14 TFSI into the PVDF matrix was developed for advanced lithium metal batteries, in which the IL serves as both electrode surface wetter and solid/electrolyte interphase modifier. [Display omitted] [ABSTRACT FROM AUTHOR]

• Cu 2 O with different facets were used to testify the shape-dependents relationship. • These Cu 2 O present different energy storage behaves in liquid and gel electrolyte. • The underlying shape-dependent of the charge-storage mechanism was discussed. The morphologies of transition metal oxides have a decisive impact on the performance of their applications. In this work, two kinds of Cu 2 O nanocrystals with preferentially exposed {100} and {111} facets corresponding to Cu 2 O nano-cube (Cu 2 O NC) and Cu 2 O nano-octahedron (Cu 2 O NO) were designed. Then the different crystallographic Cu 2 O nanocrystals were self-assembled to be flexible self-supporting Cu 2 O and reduced graphene oxide films. By the comparison of the kinetic study of Cu 2 O nanocrystal with two different exposure facets, the nanocrystal with preferentially exposed {111} behaves a larger proportion of surface-confined charging process, indicating faster ion adsorption and transferability. The specific capacity of an electrode with different exposed facets behaves as an obvious shape-dependence in the aqueous two-electrode system. In contrast with the hydrogel electrolyte system, the shape-dependence disappeared due to the sufficient ions adsorb in the slow ion diffusion electrolyte. Based on the intrinsic crystallographic plane of the cuprite Cu 2 O, the charge-storage mechanism was elucidated. The so-called "crystallography-dependence" is relevant to the dangling bonds from the exposed {111} facets, which can act as active sites for electrochemical energy storage. Furthermore, the composite of Cu 2 O NO/rGO shows a high capacity of 737.4 F g−1. The Cu 2 O NO/rGO film with exposure {111} facets demonstrated preferential adsorption of electrostatic charges on the planes and showed better charge-storage capability. In other words, there is a crystallography-dependent adsorption ability during energy storage. The Cu 2 O NO/rGO film with exposure {111} facets demonstrated preferential adsorption of electrostatic charges on the planes and showed better charge-storage capability. [Display omitted] [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries with high specific capacity are expected to play important roles in next-generation high-energy-storage systems. However, uncontrollable shuttle effect of Li polysulfide (LiPS) and safety concerns still hinder their applications. Herein, we report an in-situ formed asymmetric gel polymer electrolyte (AGPE) fabricated through a novel and low-cost strategy. In cases of modifying the separator with Lewis acid and inducing an in-situ polymerization reaction, an enclosed catholyte chamber is constructed between sulfur cathode and separator while liquid-state electrolytes still maintain in the anode side. Experimental characterizations indicate the as-prepared AGPE could effectively prevents the shuttle effect while allowing rapidly Li+ transport property. With such AGPE, the Li symmetric cells show stable cycle performance over 1400 h cycling, and Li-S batteries exhibit a high capacity of 1090 mAh g−1 with a capacity decay rate of only ∼0.2% per cycle after 200 cycles. Besides, by combining the electrochemical measurements and the evolution of sulfur species upon cycling, the origin of enhanced cycle performance is demonstrated from the perspective of reaction kinetics in this work. Our research therefore provides a novel strategy for the electrolyte configuration and reveals a promising direction for the performance improvement of Li-S batteries. [ABSTRACT FROM AUTHOR]

• The study presents gel electrolytes with optimized polymer matrix and plasticizer. • Sulfolane/ionic liquid binary plasticizer improves the properties of electrolytes. • 10-50% PMMA in polymer matrix widens the electrochemical window of the electrolyte. • The activation energy of charge transfer is comparable with Li-ion batteries. • Samples 9:1_NTf 2 and 7:3_NTf 2 have the best compatibility with a hard carbon anode. Sodium-ion batteries are emerging as an alternative to lithium-based chemistries, with several manufacturers anticipating commercial production in the short perspective. However, the use of sodium is not yet as well established as lithium and thus, requires further development to overcome the safety issues, incompatibility of sodium with many electrode materials, and limited specific energy. The presented study aims to introduce new sodium conductive gel polymer electrolytes with binary polymer matrix and binary plasticizer and discuss their compatibility with a hard carbon anode. In this study, the polymer matrix consists of polyacrylonitrile and poly(methyl methacrylate) in three mass ratios, 9:1, 7:3, and 5:5. The plasticizer is a mixture of sulfolane and imidazolium-based ionic liquid with BF 4 – or NTf 2 – anion. The measurements revealed that a small amount of PMMA improves the properties of gel electrolytes, including size stability at high temperatures, thermal properties, and transfer number of cations in the gel electrolytes. The electrochemical properties strongly depend on the anion of the ionic liquid. However, the kinetics of Na+ conduction in a hard carbon anode is favorable in the presence of an ionic liquid with NTf 2 – anion. Furthermore, systems with hard carbon anode and gel electrolyte with sulfolane/[EMIm][NTf 2 ] plasticizer exhibit activation energy of charge transfer process similar to the lithium-based chemistries. This fact makes these electrolytes good candidates for use in a sodium-ion battery. [Display omitted] [ABSTRACT FROM AUTHOR]

Single particle model (SPM) is an electrochemical model which can be used with energy balance to calculate the state of charge, terminal voltage, and temperature of the battery. The conventional SPM neglects the lithium-ion dynamics in the electrolyte, and the energy balance usually does not consider the heat transfer delay from the battery center to the surface. These lead to model errors when SPM is used for high-capacity battery cells. In this study, we propose several strategies to improve the model accuracy for high-capacity battery cells. First, the actual discharge capacity is considered by modifying the desired Li-ion flux at the electrode surface. Second, a part of the equivalent circuit model is integrated with SPM to consider the resistance in the electrolyte computationally efficiently. Third, the delay in the heat transfer from the center to the surface is represented using a second-order system dynamic. In electric vehicles, battery cells are stacked as a pack; we account for the additional heat generated by stacking pressure-induced swelling repression. Finally, parameter estimation is conducted to determine the best parameter values of the model using the experimental data. The reference values are set using a dimensionless scale-up approach. When the parameters are estimated and the model is tested with the validation data, the error percentages in the calculated terminal voltage and temperature are smaller than 2.0410% and 3.5032%, respectively, even with the cell variances. • An improved thermal SPM is proposed for the high-capacity cell. • Required lithium-ion flux is modified to consider discharge capacity variations. • A part of the equivalent circuit model is used for the resistance in electrolyte. • Heat generation due to swelling repression by stacking pressure is considered. • Dimensionless scale-up is used for parameter estimation of high-capacity cells. [ABSTRACT FROM AUTHOR]

• Ultrathin PE-CPE is prepared by using the thin PE separator and PEO/LiTFSI. • Ultrathin PE-CPE exhibits excellent cycling stability against Li metal electrodes. • FIB-SEM results revealed the uneven deposition of Li at Li/PEO interface. • PE framework restricts the ingress of Li nanoparticles through physical barrier. Solid-state lithium metal batteries (SSLBs) using solid polymer electrolytes (SPEs) still suffer from the risk of lithium dendrites, and the filling of porous framework can effectively alleviate the short-circuit problem. However, the interfacial failure mechanism of SPE with lithium metal anode and the action of porous framework filler are not fully understood. Herein, thin polyethylene (PE) separator is used as filler of poly(ethylene oxide) (PEO) to prepare ultra-thin composite polymer electrolyte (PE-CPE). Although the PE framework can greatly extend the cycling life of PE-CPE with lithium metal anode, the focused ion beam-scanning electron microscopy (FIB-SEM) results reveal that the uneven deposition and pulverization of lithium at the Li/PEO interface. Nanoparticulate lithium dendrites grow through the SPE resulting in a short-circuit, while the PE framework with small pores restricts the ingress of lithium nanoparticles through physical barrier. This work provides the growth mode of lithium dendrites in PEO-based SPE systems, and simultaneously demonstrates the role of porous framework to block lithium dendrites in SSLBs. [Display omitted] [ABSTRACT FROM AUTHOR]

Compared to rigid batteries using liquid electrolytes, solid-state batteries (SSBs) offer several advantages: flexibility, prevention of leakage, suppression of dendritic formation and hydrogen evolution, as well as minimization of cathode active material dissolution. For the materialization of real-life SSBs, gel polymer electrolytes (GPEs) are among promising candidates. However, development of GPEs with satisfying ionic conductivity and mechanical endurance is challenging. Herein, we report on the development of polyacrylamide (PAM)/phosphonated graphene oxide (PGO) nanocomposite hydrogel electrolytes for zinc-ion batteries; PGO acts as the filler through in-situ polymerization of acrylamide in an aqueous suspension of PGO. The synthesized PAM/PGO hydrogel exhibits high ionic conductivity of 31.0 mS/cm at 30 °C compared to that of PAM (13.8 mS/cm) and PAM-GO (20.8 mS/cm). The higher ionic conductivity of PAM-PGO can be attributed to its higher hydrophilicity and electrolyte storage capacity along with its lower activation energy for ionic conduction (7.2 KJ/mol K) in comparison with that of PAM (10.1 KJ/mol K) and PAM-GO (10.2 KJ/mol K). The interaction between water against PAM, PAM-GO and PAM-PGO is investigated via density-functional theory (DFT). The MnO 2 -based zinc-ion battery assembled using PAM-PGO as electrolyte shows high initial capacity of 240 mAh/g, losing only 4 and 15% of its capacity after 100 and 145 cycles, respectively. Results demonstrate promising potential of PAM-PGO as a solid-state electrolyte for flexible battery applications. [ABSTRACT FROM AUTHOR]

• The RGO-wrapped Li2MoO4@Li-NMC111 cathode material and nano-composite gel polymer electrolytes (NGPEs) are developed for rechargeable Li-battery. • 5 wt.% MCM-41 containing NGPE shows high lithium transference number and Li-ion conductivity at 30 °C (t L i + = ∼ 0.49 and σ L i + = ∼4.4 × 10−3 s cm−1). • The RGO-wrapped Li2MoO4@Li-NMC111 cathode shows better Li-ion diffusion coefficient, rate capability and specific energy density as compare to pristine cathode. • The Li/5 wt.% MCM-41 containing NGPE/RGO-wrapped Li2MoO4@Li-NMC111 cell delivers the specific energy density of ∼728 mWh g − 1 at 0.2C at 30 °C. • 5 wt.% MCM-41 containing NGPE shows better cycle stability at 30 °C and 70 °C as compare to the commercial LiPF6:EC:DEC:DMC electrolyte. A long cycle-stability and safety is key requirement for the large-scale application of rechargeable Li-batteries. In this study, a thin double-layer (reduce graphene oxide and Li 2 MoO 4) coated Li-NMC111 cathode is successfully synthesized which delivers improved electrochemical performance such as higher specific energy density and better rate capability, as compared to the pristine Li-NMC111. Furthermore, a freestanding/flexible nano-composite gel polymer electrolyte (NGPEs) is successfully prepared by solution cast technique and found suitable for high-temperature Li-battery applications. The developed 5 wt.% MCM-41 containing NGPE (NGPE#1) not only facilitates enhanced Li-ion conductivity of ∼4.4 ✗ 10−3 S cm−1 at 30 °C but also prevents uncontrolled lithium dendrite growth. The RGO-wrapped Li 2 MoO 4 @Li-NMC111 cathode with optimized NGPE#1 delivers high specific discharge capacity (∼211 mAh g − 1 at 0.2C and ∼157 mAh g − 1 at 0.5C) and specific energy density (∼728 mWh g − 1 at 0.2C and ∼520 mWh g − 1 at 0.5C) as compared to pristine Li-NMC111 cathode. Moreover, after 100 cycles, the discharge capacity of RGO-wrapped Li 2 MoO 4 @Li-NMC111 with optimized NGPE#1 is obtained ∼150 mAh g − 1 at 0.5C, with 75% capacity retention of the maximum capacity. In addition, at 70 °C, the specific discharge capacity of Li/RGO-wrapped Li 2 MoO 4 @Li-NMC111 cell with optimized NGPE#1 is obtained ∼186 mAh g − 1 at 0.5C. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel lithium-oxygen (Li-O 2 ) battery with a polymer gel electrolyte (PGE) membrane is successfully prepared. The membrane is a blend of cellulose acetate (CA) and poly(vinylidene fluoride- co -hexafluoropropylene) (P(VDF-HFP)) and is fabricated using a solution casting technique followed by impregnation with lithium bis(trifluoromethane sulfonimide) (LiTFSI) solution. We demonstrate that the PGE membrane has good electrolyte uptake and shows high ionic conductivity as well as excellent thermal and electrochemical stability. A Li-O 2 battery containing our PGE as the electrolyte and separator exhibits good rate capability and enhanced cycling capacity retention compared to a battery using commercial liquid electrolyte and a polyethylene (PE) separator under the same conditions. We attribute this enhanced performance to the PGE, which maybe restrain the diffusion of oxygen from the air cathode to the Li metal anode. This study may prove valuable for resolving the problem of poor cycling stability in Li-O 2 batteries caused by oxygen diffusion from cathode to anode. [ABSTRACT FROM AUTHOR]