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Summary: During heating of oils, trans fatty acids can be formed via various chemical reactions, which are not treated as free fatty acids but as part of triglycerides. The factors that influence the formation of trans isomers of α‐linolenic acid (TALAs) and the correlation between TALAs and total polar components were studied by heating linseed oil. Both heating temperature and time affected TALA formation. Increasing temperature from 170 °C to 200 °C for 2 h produced more TALAs than conducting 14 h heating at 170 °C. Pumping air promoted oxidation of α‐linolenic acid, reducing the content of TALAs, especially c9, c12, t15‐C18:3. TALA contents were positively correlated with total polar components, triglyceride oligomer, triglyceride dimer and diglyceride (DG) (r = 0.456–0.813), but negatively correlated with free fatty acids (r = −0.650–‐0.469). No correlation was found between TALAs and oxidised triglyceride monomer. Compared with di‐TALAs, mono‐TALAs had stronger correlation with DG. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a hierarchically porous and ultrathick “breathable” wood‐based cathode for high‐performance Li‐O2 batteries is developed. The 3D carbon matrix obtained from the carbonized and activated wood (denoted as CA‐wood) serves as a superconductive current collector and an ideal porous host for accommodating catalysts. The ruthenium (Ru) nanoparticles are uniformly anchored on the porous wall of the aligned microchannels (denoted as CA‐wood/Ru). The aligned open microchannels inside the carbon matrix contribute to unimpeded oxygen gas diffusion. Moreover, the hierarchical pores on the microchannel walls can be facilely impregnated by electrolyte, forming a continuous supply of electrolyte. As a result, numerous ideal triphase active sites are formed where electrolyte, oxygen, and catalyst accumulate on the porous walls of microchannels. Benefiting from the numerous well‐balanced triple‐phase active sites, the assembled Li‐O2 battery with the CA‐wood/Ru cathode (thickness: ≈700 µm) shows a high specific area capacity of 8.58 mA h cm−2 at 0.1 mA cm−2. Moreover, the areal capacity can be further increased to 56.0 mA h cm−2 by using an ultrathick CA‐wood/Ru cathode with a thickness of ≈3.4 mm. The facile ultrathick wood‐based cathodes can be applied to other cathodes to achieve a super high areal capacity without sacrificing the electrochemical performance. [ABSTRACT FROM AUTHOR]

Abstract: A biocompatible nanovalve attached to the surface of MCM-41 mesoporous nanoparticles is designed to release encapsulated guest molecules controllably under pH activation. This nanovalve system is comprised of α-cyclodextrin (α-CD) rings that encircle p-anisidino linkers, and can be tuned to respond under specific pH conditions through chemical modification of the linkers. One of the distinctive features of this functional nanovalve system lies in its excellent bio-stability and durability in cell culture medium solution, the binding between the α-CD and p-anisidino groups was not interrupted or disintegrated by the proteins in the DMEM solution without adjusting the pH value. Luminescence spectroscopy demonstrates that the on-command pH-activated system displays very good bio-stability—no drug leakage at pH ∼7.4 and excellent drug release performance not only in H2O but also in cell culture medium at pH ∼5.5. [Copyright &y& Elsevier]

Abstract: By using different dual-template combinations, four types of mesoporous silica materials with different morphologies were successfully synthesized. A solid-sphere mesoporous (SSM) silica was obtained using a combination of tri-block copolymer (F127) and 1,12-diaminododecane (DADD), but when F127 was substituted with poly(vinylpyrrolidone) (PVP), a leaf-shaped mesoporous (LSM) silica was obtained. In addition, a hollow-sphere mesoporous (HSM) silica was obtained by using a combination of PVP and dodecylamine (DDA), but a cotton-like mesoporous (CLM) silica was obtained using F127 instead of PVP. All four types of synthesized materials were characterized by SEM, TEM, XRD, and N2 adsorption–desorption isotherms, and the results showed that all of them exhibited high surface area, large pore volume, worm-like pore structure, and beautiful shapes. The results of storage experiments revealed that the HSM and CLM showed good adsorption and storage properties. The HSM (the largest pore volume) seemed to have the larger storage capacity when compared to the CLM, albeit CLM had the highest surface area among all. [Copyright &y& Elsevier]

Liu, L.; Song, H.; and Xing, J., 2019. Benchmarking of marine equipment manufacturing industry in Liaoning province. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 838–841. Coconut Creek (Florida), ISSN 0749-0208. This article constructs an evaluation index system for the competitiveness of marine equipment manufacturing industry from six aspects: industrial scale, economic benefits, international competitiveness, asset management capabilities, innovation capabilities, and social benefits. And it is measured by 14 relatively objective, complete, and quantifiable indicators. Taking the marine equipment manufacturing industry in 12 provinces and cities such as Liaoning, Jiangsu, Shandong, Guangdong, Shanghai and Zhejiang as the research object, quantify this approach of the competitiveness level of seven sub-sectors in the selected 12 provinces and cities in the marine equipment manufacturing industry based on competitive evaluation theory, then comprehensively evaluated and simply sorted, and based on the research to calculate results. Finally, identify the provinces and cities which has characteristics of individual advantage of competitiveness level. As a benchmark province, which will compare the competitive status with that of Liaoning's marine equipment manufacturing industry in order to find out the gaps and identify the reasons. [ABSTRACT FROM AUTHOR]

Abstract: A hollow sphere neodymium embedded mesoporous silica material (NEMS) has been synthesized successfully by using neutral 1,12-diaminododecane as template and embedding Nd into the framework simultaneously. It is interesting that a lamellar structured material with MSU-V structure was obtained if only DADD was used as template without embedding of Nd. The synthesized materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), BET method, thermal gravimetry/differential thermal analysis (TG/DTA), and X-ray photoelectron spectroscopy (XPS). The hollow sphere morphology was observed by TEM images and clearly revealed the structure of NEMS molecular sieves. Both XRD and XPS results confirmed that the Nd atoms were incorporated into the framework of mesoporous materials. The TG/DTA results verified the good thermal stability of the synthesized NEMS material. The surface area of samples with Si/Nd molar ratio from 10 to 60 reached from 543 to 1103m2 g−1, respectively. It also found that the Nd embedded mesoporous silica material showed good catalytic activity and selectivity towards the oxidation of styrene, proportional to the neodymium content in the catalysts. [Copyright &y& Elsevier]

Neodymium complexes (Nd(DBM)3·H2O and Nd(DBM)3·Phen) were studied by photoacoustic spectroscopy from near-IR to mid-IR region. Low excited energy levels, relaxation processes of the complexes and the nephelauxetic effect were discussed according to the comparison with electron absorption spectra of free neodymium ion. The interaction between Nd(III) and the ligands in solid complexes was investigated on the basis of band shifts and intensity change. [Copyright &y& Elsevier]

The amplitude and the phase of the photoacoustic (PA) signal generated in Nd(DBM)3 and Nd(DBM)3·Phen (DBM: dibenzoylmethane; Phen: 1,10-phenanthroline) complex powders were examined. By using PA amplitude and phase spectra, together with IR and fluorescence spectra, the intramolecular relaxation processes and the fluorescence properties of DBM were studied. And a new method to calculate the relaxation time of the ligand of rare earth complexes was presented. Compared with the free ligand DBM, the relaxation time of DBM in Nd(DBM)3 and Nd(DBM)3·Phen complexes calculated by the new method had the order: free ligand>in Nd(DBM)3>in Nd(DBM)3·Phen. The fluorescence spectra verified the validity of the new method. The intramolecular energy transfer models were established on the basis of the calculated results and the fluorescence spectra. [Copyright &y& Elsevier]

The photoacoustic (PA) amplitude spectra of Eu(Dbm)3Phen, Eu0.8Gd0.2(Dbm)3Phen and Eu0.8Nd0.2(Dbm)3Phen complexes (Dbm: dibenzoylmethane; Phen: phenanthroline) have been measured, and the PA phase data of the different complexes calculated. The PA amplitude spectra combined with the luminescence spectra reflected the variation of the luminescence efficiency, and the PA phase is directly relative to the lifetime of Eu3+5D0 level. The luminescence efficiency and the lifetime of Eu3+5D0 level increase when Gd3+ is introduced, while they decrease greatly when Nd3+ is added, which is due to the different intermolecular energy transfer processes. The models of energy transfer and relaxation processes of Eu0.8Gd0.2(Dbm)3Phen and Eu0.8Nd0.2(Dbm)3Phen are established. [Copyright &y& Elsevier]

Efficient, stable, and inexpensive electrocatalysts are essential to overcome the high overpotential and slow kinetics of the oxygen evolution reaction (OER) process during water electrolysis applications. 2D transition metal carbides (MXene) show great potential in functional heterogeneous interface engineering for electrocatalytic OER. However, it is still a challenge to regulate the interlayer space and realize the heterogeneous layer‐by‐layer ordered embedding for MXene. Herein, a simple hydrothermal‐assisted strategy is proposed to prepare highly conductive Ti3C2Tx MXene supported by synergized Ni2+, Co2+, and Fe3+ with bilayer H2O, which significantly enlarges the interlayer distances and improves the interlayer ion concentrations. Benefiting from modulated interface chemistry, embedded metal ions undergo multi‐directional in situ growth on the MXene substrate, thereby forming a stable 0D/2D@2D nano‐hybrid material (NiFe/MX‐HT). Combining density functional theory calculations with experiments demonstrates that MXene offers a framework for electron transfer, enhances the exposure of active sites, modulates the electronic structure, and greatly reduces the energy barrier of the rate‐determining step in the process of OER. Thus, NiFe/MX‐HT requires only 230 mV to achieve 10 mA cm−2 and maintains stability even after operating at 100 mA cm−2 for 150 h. This work offers new insights into exploring various functional MXene‐based heterogeneous materials. [ABSTRACT FROM AUTHOR]

Quasi‐solid polymer electrolyte (QPE) lithium (Li)‐metal battery holds significant promise in the application of high‐energy‐density batteries, yet it suffers from low ionic conductivity and poor oxidation stability. Herein, a novel self‐built electric field (SBEF) strategy is proposed to enhance Li+ transportation and accelerate the degradation dynamics of carbon‐fluorine bond cleavage in LiTFSI by optimizing the termination of MXene. Among them, the SBEF induced by dielectric Nb4C3F2 MXene effectively constructs highly conductive LiF‐enriched SEI and CEI stable interfaces, moreover, enhances the electrochemical performance of the QPE. The related Li‐ion transfer mechanism and dual‐reinforced stable interface are thoroughly investigated using ab initio molecular dynamics, COMSOL, XPS depth profiling, and ToF‐SIMS. This comprehensive approach results in a high conductivity of 1.34 mS cm−1, leading to a small polarization of approximately 25 mV for Li//Li symmetric cell after 6000 h. Furthermore, it enables a prolonged cycle life at a high voltage of up to 4.6 V. Overall, this work not only broadens the application of MXene for QPE but also inspires the great potential of the self‐built electric field in QPE‐based high‐voltage batteries. [ABSTRACT FROM AUTHOR]

Quasi‐solid polymer electrolyte (QPE) lithium (Li)‐metal battery holds significant promise in the application of high‐energy‐density batteries, yet it suffers from low ionic conductivity and poor oxidation stability. Herein, a novel self‐built electric field (SBEF) strategy is proposed to enhance Li+ transportation and accelerate the degradation dynamics of carbon‐fluorine bond cleavage in LiTFSI by optimizing the termination of MXene. Among them, the SBEF induced by dielectric Nb4C3F2 MXene effectively constructs highly conductive LiF‐enriched SEI and CEI stable interfaces, moreover, enhances the electrochemical performance of the QPE. The related Li‐ion transfer mechanism and dual‐reinforced stable interface are thoroughly investigated using ab initio molecular dynamics, COMSOL, XPS depth profiling, and ToF‐SIMS. This comprehensive approach results in a high conductivity of 1.34 mS cm−1, leading to a small polarization of approximately 25 mV for Li//Li symmetric cell after 6000 h. Furthermore, it enables a prolonged cycle life at a high voltage of up to 4.6 V. Overall, this work not only broadens the application of MXene for QPE but also inspires the great potential of the self‐built electric field in QPE‐based high‐voltage batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • A concept of multifunctional Li+ traffic controller is proposed. • The traffic controller can effectively regulate the distribution of Li+. • The traffic controller stabilizes the electrode-electrolyte interface. • The traffic controller layer enables ultra-low N/P ratio full cells. The performance of thin lithium metal anodes is affected due to issues that weaken the electrode-electrolyte interphase. In this work, a coating layer serving as a Li+ traffic controller based on hexadecyl trimethyl ammonium bis(trifluoromethanesulphonyl)imide ([CTA][TFSI]) and poly (vinylidene difluoride co-hexafluoropropylene) (P(VDF-HFP)) is used to stabilize the thin lithium metal interface. The CTA+ ions in the coating layer can effectively regulate the distribution of Li+ concentration to promote uniform deposition of lithium. The anion of [CTA][TFSI] can optimize solid electrolyte interphase (SEI) with inorganic-rich components, which improve the ionic conductivity and reaction kinetics. Furthermore, the flexible polymer skeleton can fortify the fragile SEI, facilitating the consistent operation of the battery. Due to these improvements, a thin Li metal anode (4 mAh cm−2) with a coating layer in a Li||Li symmetric cell demonstrates a lifespan of 600 h at 1 mA cm−2 and 1 mAh cm−2. Notably, full cells with an ultra-low negative electrode/positive electrode = 1 (N/P = 1) demonstrate a stable performance over 200 cycles and 90 cycles at 0.5C and 1C (1C = 170 mA g−1), respectively. [ABSTRACT FROM AUTHOR]

Block copolymer electrolytes are of great interest due to the combination merits of ion conduction and mechanical strength. However, there lacks a comprehensive understanding on the role of nanodomain spacing in ion‐dipole coordinating environment and interface environment. Herein, the lithium salts with varied binding energy are chosen to tune nanodomain spacing in Polyether‐block‐Polyamide (PEO‐PA) polymer. Spectra characterizations in combination with molecular dynamic simulations systematically demonstrate adding LiFSI salts with lower binding energy contributes to forming larger PEO nanodomain spacing and clarifies the relationship between nanodomain spacing and ion‐dipole coordinating environment as well as interface environment. The larger PEO nanodomain spacing in LiFSI doping PEO‐PA electrolytes (AEOF) creates a loosely Li+‐EO group coordinating environment and improves pristine interface contact. In addition, the formation of solid‐electrolyte interphase rich in LiF and Li3N enhances interfacial stability. Therefore, the ionic conductivity of AEOF electrolytes is significantly improved. Furthermore, the Li||AEOF||Li cells exhibit extraordinary cycling life over 10000 h (416 days) at 0.1 mA cm−2 with a capacity of 0.1 mAh cm−2. This study provides a new insight into the ion‐dipole coordinating environment and interface environment, which benefits the theory‐guided design of all‐solid‐state polymer electrolytes. [ABSTRACT FROM AUTHOR]

Proton exchange membrane water electrolysis is hindered by the sluggish kinetics of the anodic oxygen evolution reaction. RuO2 is regarded as a promising alternative to IrO2 for the anode catalyst of proton exchange membrane water electrolyzers due to its superior activity and relatively lower cost compared to IrO2. However, the dissolution of Ru induced by its overoxidation under acidic oxygen evolution reaction (OER) conditions greatly hinders its durability. Herein, we developed a strategy for stabilizing RuO2 in acidic OER by the incorporation of high-valence metals with suitable ionic electronegativity. A molten salt method was employed to synthesize a series of high-valence metal-substituted RuO2 with large specific surface areas. The experimental results revealed that a high content of surface Ru4+ species promoted the OER intrinsic activity of high-valence doped RuO2. It was found that there was a linear relationship between the ratio of surface Ru4+/Ru3+ species and the ionic electronegativity of the dopant metals. By regulating the ratio of surface Ru4+/Ru3+ species, incorporating Re, with the highest ionic electronegativity, endowed Re0.1Ru0.9O2 with exceptional OER activity, exhibiting a low overpotential of 199 mV to reach 10 mA cm−2. More importantly, Re0.1Ru0.9O2 demonstrated outstanding stability at both 10 mA cm−2 (over 300 h) and 100 mA cm−2 (over 25 h). The characterization of post-stability Re0.1Ru0.9O2 revealed that Re promoted electron transfer to Ru, serving as an electron reservoir to mitigate excessive oxidation of Ru sites during the OER process and thus enhancing OER stability. We conclude that Re, with the highest ionic electronegativity, attracted a mass of electrons from Ru in the pre-catalyst and replenished electrons to Ru under the operating potential. This work spotlights an effective strategy for stabilizing cost-effective Ru-based catalysts for acidic OER. [ABSTRACT FROM AUTHOR]

Garnet Li7La3Zr2O12 (LLZO) is regarded as a promising solid electrolyte due to its high Li+ conductivity and excellent chemical stability, but suffers from grain boundary resistance and porous structure which restrict its practical applications in lithium–metal batteries. Herein, a novel and highly efficient TiO2‐induced conversion strategy is proposed to generate Li ion‐conductive Li0.5La0.5TiO3, which can simultaneously eliminate the pre‐existing pores/voids and contamination Li2CO3. The Li/LLZTO‐5TiO2/Li symmetric cell exhibits a high critical current density of 1.1 mA cm−2 at 25°C, and the long‐term lithium cycling stability of over 1500 h at 0.1 mA cm−2. More importantly, the excellent performance of LLZTO‐5TiO2 electrolyte is verified by LiCoO2/LiFePO4 coupled full cells. For example, The LiCoO2 coupled full cell exhibits a significant discharge rate capacity of 108 mAh g−1 at 0.1 C, and a discharge capacity retention rate of 91.23% even after 150 cycles of charge and discharge. COMSOL Multiphysics and density functional theory calculation reveal that LLZTO‐5TiO2 electrolyte has a strong lithium affinity and uniform Li ions distribution, which can improve the cycle stability of Li–metal batteries by preventing dendrite growth. [ABSTRACT FROM AUTHOR]

[Display omitted] Solid-state polymer electrolytes are outstanding candidates for next-generation lithium metal batteries in the realm of high specific energy densities, high safeties and tight contact with electrodes. However, their applications are still hindered by the limitations that no single polymer is electrochemically stable with the oxidizing high-voltage cathode and the highly reductive Li anode, simultaneously. Herein, a bilayer asymmetric polymer electrolyte (SL-SPE) without accessional interface resistance that using poly (ethylene glycol) diacrylate (PEGDA) as a "bridge" to connect the sulfonyl (O S = O)-contained oxidation-tolerated layer and polyether-derived reduction-tolerated layer (SPE), is proposed and synthesized by sequential two-step UV polymerizations. SL-SPE can provide widened electrochemical stability window up to 5 V, while simultaneously deploying a stable Janus interface property. Eventually, the superior high-voltage (4.4 V) cycling durability can be displayed in LiNi 0.6 Co 0.2 Mn 0.2 O 2 |SL-SPE|Li batteries. This finding provides a bran-new idea for designing multifunctional polymer electrolytes in the application of solid-state batteries. [ABSTRACT FROM AUTHOR]

Assembling molecular proton carriers into crosslinked networks is widely used to fabricate proton conductors, but they often suffer losses in conduction efficiency and stability accompanied by unclear causes. Covalent organic frameworks (COFs), with well‐defined crystal frameworks and excellent stability, offer a platform for exploring the proton transfer process. Herein, a strategy to construct proton conductors that induce conductivity and stability by introducing bottom‐up hierarchical structure, mass transport interfaces, and host–guest interactions into the COFs is proposed. The proton‐transport platforms are designed to possess hierarchically macro–microporous structure for proton storage and mass transport. The protic ionic liquids, with low proton dissociation energies investigated by DFT calculation, are installed at open channel walls for faster proton motion. As expected, the resultant proton conductors based on a covalent organic framework (PIL0.5@m‐TpPa‐SO3H) with hierarchical pores increase conductivity by approximately three orders of magnitude, achieving the value of 1.02 × 10−1 S cm−1 (90 °C, 100% RH), and maintain excellent stability. In addition, molecular dynamics simulations reveal the mechanism of "hydrogen‐bond network" for proton conduction. This work offers a fresh perspective on COF‐based material manufacturing for high‐performance proton conductors via a protocol of macro‐micropores. [ABSTRACT FROM AUTHOR]

The development of effective, stable anhydrous proton‐conductive materials is vital but challenging. Covalent organic frameworks (COFs) are promising platforms for ion and molecule conduction owing to their pre‐designable structures and tailor‐made functionalities. However, their poor chemical stability is due to weak interlayer interactions and intrinsic reversibility of linkages. Herein, we present a strategy for enhancing the interlayer interactions of two‐dimensional COFs via importing planar, rigid triazine units into the center of C3‐symmetric monomers. The developed triazine‐core‐based COF (denoted as TPT‐COF) possesses a well‐defined crystalline structure, ordered nanochannels, and prominent porosity. The proton conductivity was ≈10 times those of non‐triazinyl COFs, even reaching up to 1.27×10−2 S cm−1 at 160 °C. Furthermore, the TPT‐COF exhibited structural ultrastability, making it an effective proton transport platform with remarkable conductivity and long‐term durability. [ABSTRACT FROM AUTHOR]

The development of effective, stable anhydrous proton‐conductive materials is vital but challenging. Covalent organic frameworks (COFs) are promising platforms for ion and molecule conduction owing to their pre‐designable structures and tailor‐made functionalities. However, their poor chemical stability is due to weak interlayer interactions and intrinsic reversibility of linkages. Herein, we present a strategy for enhancing the interlayer interactions of two‐dimensional COFs via importing planar, rigid triazine units into the center of C3‐symmetric monomers. The developed triazine‐core‐based COF (denoted as TPT‐COF) possesses a well‐defined crystalline structure, ordered nanochannels, and prominent porosity. The proton conductivity was ≈10 times those of non‐triazinyl COFs, even reaching up to 1.27×10−2 S cm−1 at 160 °C. Furthermore, the TPT‐COF exhibited structural ultrastability, making it an effective proton transport platform with remarkable conductivity and long‐term durability. [ABSTRACT FROM AUTHOR]

Abstract: A novel core–shell structured AuPt@Pd/C catalyst for the electrooxidation of formic acid is synthesized by a pulse electrodeposition process, and the AuPt core nanoparticles are obtained by a NaBH4 reduction method. The catalyst is characterized with X-ray powder diffraction and transmission electron microscopy, thermogravimetric analysis, cyclic voltammetry, CO stripping and X-ray photoelectron spectroscopy. The core–shell structure of the catalyst is revealed by the increase in particle size resulting from a Pd layer covering the AuPt core, and by a negative shift in the CO stripping peaks. The addition of a small amount of Pt improves the dispersion of Au and results in smaller core particles. The catalyst's activity is evaluated by cyclic voltammetry in formic acid solution. The catalyst shows excellent activity towards the anodic oxidation of formic acid, the mass activity reaches 4.4 A mg−1 Pd and 0.83 A mg−1 metal, which are 8.5 and 1.6 times that of commercial Pd/C. This enhanced electrocatalytic activity could be ascribed to the good dispersion of Au core particles resulting from the addition of Pt, as well as to the interaction between the Pd shell layer and the Au and Pt in the core nanoparticles. [Copyright &y& Elsevier]

Abstract: Co submicrospheres with the typical diameter of ca. 500nm, and possessing beautiful morphologies composed of dense Co nanosheets ca. 10nm thick, were synthesized by a facile and low-cost complexant-assisted hydrothermal approach. Magnetic measurement at room temperature indicated the coercivity of the submicrospheres reached 268Oe, which was much higher than that of bulk Co and of some microstructure cobalt materials reported previously. Hexagonal close-packed (hcp) and face-centered cubic (fcc) cobalt phases in the materials were identified by X-ray diffractometer (XRD). It was revealed that the addition of the complexant sodium tartrate played a crucial role in the formation of the hierarchical architectures of the Co submicrospheres. We believe that the high coercivity of the synthesized submicrospheres may result from their special nano-micro structure, and we suggest that this low-cost and facile synthesis approach can be used for large-scale production of Co magnetic materials with special structures and morphologies, as well as excellent magnetic properties. [Copyright &y& Elsevier]

Lithium–sulfur (Li–S) batteries are one of the most promising next‐generation energy storage systems due to their ultrahigh theoretical specific capacity. However, their practical applications are seriously hindered by some inevitable disadvantages such as the insulative nature of sulfur and Li2S, volume expansion of the cathode, the shuttle effect of polysulfides, and the growth of lithium dendrites on the anode. Of these, the polysulfide shuttle effect is one of the most critical issues causing the irreversible loss of active materials and rapid capacity degradation of batteries. Herein, modified separators with functional coatings inhibiting the migration of polysulfides are enumerated based on three effects toward polysulfides: the adsorption effect, separation effect, and catalytic effect. To solve the shuttle effect problem, researchers have replaced liquid electrolytes with solid‐state electrolytes. In this review, solid‐state electrolytes for lithium–sulfur batteries are grouped into three categories: inorganic solid electrolytes, solid polymer electrolytes, and composite solid electrolytes. Challenges and perspectives regarding the development of an optimized strategy to inhibit the polysulfide shuttle for enhancing cycle stability in lithium–sulfur batteries are also proposed. [ABSTRACT FROM AUTHOR]

Stable and active Pt electrocatalyst preparation by a modified citrate reduction method and a mechanism analysis of inorganic additives. • Pt with a clean surface were synthesized via a modified citrate reduction method. • NO 2 − ions possibly alter the reaction kinetics of the growth of Pt NPs. • The optimized Pt/CNT demonstrated high mass activity and moderate activity decay. • The maximum power density of the optimized Pt/CNT catalysts at 0.6 V is 744 mW cm−2. Ultra-small and monodispersed Pt nanoparticles (NPs) have been successfully synthesized in polymer electrolyte membrane fuel cells. The process normally involves the use of capping agents, organic species, templates, and substrates and is thus complex. Hence, obtaining Pt NPs with a clean surface is challenging. In this study, a method for preparing stable and highly dispersed Pt NPs with clean surfaces is proposed. The method involves the use of a modified Na 3 C 6 H 5 O 7 reduction process assisted by NaNO 3 stabilization. The specific complexations of NO 2 − ions possibly alter the reaction kinetics and lower the growth rate of Pt NPs by retarding the reduction reaction. The optimized Pt/carbon nanotube (CNT) catalysts exhibit high mass activity and moderate activity decay after 10,000 times of potential cycling compared with commercially available Pt/C catalysts. Then, membrane electrode assemblies based on the resultant catalysts are characterized. The cell performance of 744 mW cm−2 (maximum power density) is achieved after the optimized Pt/CNT catalysts are used in carbon black. [ABSTRACT FROM AUTHOR]

Surface engineering has been identified as an effective way to maximize the utilization of noble atoms and facilitate the oxygen reduction reaction. However, a cost-effective and highly durable platform for tailoring the electrocatalytic activity, is still absent. Herein, we demonstrate a new and promising catalytic material of antiperovskite-typed PdNFe 3 and construct a high performance PdNFe 3 @Pd catalyst with atomic layers of strained Pd shell. The PdNFe 3 @Pd/C catalyst presents a high mass activity (MA) of 1.14 A mg−1 Pd at 0.9 V, which is 9 and 6 times higher than those of the Pt/C and Pd/C, respectively. More importantly, the excellent performance of PdNFe 3 @Pd/C was also verified in anion-exchange membrane fuel cells and rechargeable Zn−air batteries. Density functional theory calculations reveal that the strain effect aroused by the lattice mismatch between PdNFe 3 core and Pd shell contributes to the enhanced ORR performance by optimizing the binding strength of oxygen intermediates on Pd. [Display omitted] • Demonstrating a new class of platform/core materials for constructing core-shell catalysts. • Elucidating catalytic mechanism of PdNFe 3 @Pd towards ORR. • Extraordinary catalytic performance towards oxygen reduction. [ABSTRACT FROM AUTHOR]

Abstract: Through decorating commercial Pt/C catalyst with a binary oxide of silicon and tin, a catalyst with significantly enhanced self-humidification capacity and ultra-high stability has been successfully prepared. After 5000 cycles, ECSA and ORR activity decay by only 30% and 28.4%, respectively, for our optimal decorated catalyst, compared with 75% and 99.9% for undecorated Pt/C under the same conditions. We attribute this improvement to the prevention of Pt nanoparticle aggregation and the synergistic effects between the Pt active component and the binary oxide. The decorated catalyst also exhibits excellent self-humidification. Under non-humidified operating conditions, a membrane electrode assembly (MEA) with a decorated Pt/C catalyst anode is discharged at 0.6 V for 8 h with only slight current density decay, whereas serious decay is observed for an MEA with a non-decorated Pt/C anode. The catalysts are characterized using XRD, SEM/TEM, XPS, and contacted angle measurement. We find that the dissolution, migration, and aggregation of Pt nanoparticles can be effectively prevented by decoration with the binary oxide, and that the contact angle is decreased by 56°, indicating great improvement in the catalyst’s wettability. The interactions between Pt and oxide, Sn and Si are revealed by XPS analysis. This work may provide a facile and effective way to address the durability and humidification issues of PEM fuel cells.Graphical Abstract: An oxide modified Pt/C catalyst was prepared by decorating the commercial Tanaka Pt/C catalyst with a binary oxide of Sn and Si, the catalyst exhibited significantly enhanced stability/durability, slightly enhanced activity and excellent self-humidification property. The catalysts were characterized with HRTEM, XPS etc. The enhancements should be attributed to the prevention of the coated binary oxide to the aggregation of Pt, the corrosion of carbon support. And self-humidification may be resulted from the wettability of the silicon oxide. [ABSTRACT FROM AUTHOR]

A series of La(OH) 3 -modified magnetic pineapple biochar (La x -MC) with different contents of La(OH) 3 were prepared and used as phosphate adsorbents for the first time. With the increase of La(OH) 3 content, the adsorption capacity for phosphate increased while the magnetic property decreased. La10-MC exhibited excellent magnetic property for easy recovery and high adsorption capacity up to 101.16 mg P/g, which was 27 times that of pineapple biochar and much higher than most phosphate adsorbents. Adsorption isotherm and adsorption kinetics were better fitted by Langmuir model and pseudo second-order model, respectively. The removal efficiency >96.04% in coexisting ions indicated its high selectivity to phosphate. Little decrease in removal efficiency after three adsorption-desorption cycles suggested its excellent stability and cyclic utilization. Leaching study demonstrated the negligible risk of La 3+ and Fe 3+ leakage during adsorption process. Mechanism study revealed that the adsorption mechanism involved precipitation, electrostatic interaction, ligand exchange and inner-sphere complexation. [ABSTRACT FROM AUTHOR]

The wettability, or hydrophobic-hydrophilic balance, of cathode catalyst layer influences the performance of the proton exchange membrane fuel cell. In this paper, cathode catalyst layer with different polytetrafluoroethylene contents are prepared, and the effect of hydrophobic-hydrophilic balance on the performance of the membrane electrode assembly is investigated intensively. It is found that wettability, or hydrophobic-hydrophilic balance, of cathode catalyst layer can significantly affect the performance of membrane electrode assembly, and it can be effectively tuned by varying the loading of polytetrafluoroethylene. With the addition of polytetrafluoroethylene, the hydrophobicity of cathode catalyst layer, reflected by the contact angel, can be changed from 135.6° of that without addition of polytetrafluoroethylene to 146.5° with 70 wt.% polytetrafluoroethylene addition, and the optimal addition amount is 50 wt.%. For our optimal membrane electrode assembly with optimal addition of polytetrafluoroethylene in cathode, its current density are recorded as 990 mA cm –2  at 0.7 V and 1400 mA cm –2  at 0.6 V, respectively; its maximum power density is up to 856 mW cm −2 . Furthermore, our polytetrafluoroethylene-incorporated membrane electrode assembly also exhibits excellent stability, and current density only drops from 1000 mA cm −2 to 900 mA cm −2 after a continuous operation of 60 h. [ABSTRACT FROM AUTHOR]

High-performance ferric phosphate (FePO 4 ), with well-defined ellipsoid morphology and uniform particle size distribution, is successfully fabricated via a green spray drying method with formic acid as additive. It is found that the added formic acid plays a crucial role for the formation of the well-distributed FePO 4 particles. Benefited by the outstanding structure and properties of ferric phosphate prepared above, a high performance of lithium iron phosphate (LiFePO 4 ) has been prepared. It exhibits high capacity, especially at high charging/discharging rate (158.4 mAh g −1 at 0.2 C and 107.3 mAh g −1 at 10 C), and excellent cycling stability (without capacity fading after cycling for 200cycles at 1 C). All these impressive electrochemical performance could be ascribed to the FePO 4 precursor, and further attributed to the addition of formic acid, which may play as a template, resulting in the well-defined morphology, uniform particles size distribution, hierarchical pore structure, and high surface area of the ferric phosphate. [ABSTRACT FROM AUTHOR]

The performance of the proton exchange membrane fuel cell (PEMFC) is significantly improved through introducing nitrogen-doped carbon nanotubes (NCNTs) into the catalyst layer (CL) and microporous layer (MPL) of the membrane electrode assembly (MEA), it reveals by SEM images that the NCNTs are uniformly dispersed in CL and MPL, resulting in the more plenty of porosity, higher surface area, better conductivity, and better prevention of the layer cracks. The BET surface area and pore volume of MPL are increased by 88% and 77% respectively with the addition of 20 wt% of NCNTs in MPL. The membrane electrode assembly (MEA) with adding 20 wt% NCNTs both in cathode CL and in cathode GDL can yield the best cell performance. At a cell temperature of 70 °C and 30 psi back pressures, the current density is up to 1000 mA cm −2 at 0.7 V and 1600 mA cm −2 at 0.6 V, and the max power density reaches 997 mW cm −2 . [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries have sparked a lot of interests because of their high specific capacity and low cost. However, due to the 'shuttle effect', unstable Li metal and side reactions, the performance of LSBs is less than expected. Herein, we design a localized high-concentration electrolyte (LHCE), using carbonate as the base solvent, hexafluoroisopropyl methyl ether (HFME) as the diluent, and vinylene carbonate (VC) as the filmogen to realize a stable solid-solid cyclic process in LSBs. For the cathode side, carbonate solvent molecules with Li+-coordination can reduce the nucleophilic side reactivity with lithium sulfide. The initial surface reaction between VC and lithium sulfide forms an effective cathode electrolyte interface (CEI), which can continuously protect the cathode active substances and realize a stable solid-solid conversion process. For the anode side of lithium metal, in combination with Li+-coordinated TFSI− in LHCE, a stable solid electrolyte interface (SEI) can be formed by VC on Li anode which improves the stability of Li anode. As a result, the cyclic performance of LSBs is significantly improved, demonstrating a high specific capacity and stability. Furthermore, the self-discharge is nearly stopped. This work provides a universal strategy to design new electrolytes to improve Li–S battery performance. [Display omitted] • A localized high-concentration carbonate electrolyte for Li–S batteries is designed. • Simple strategy to simultaneously synthesize CEI and SEI films. • Elimination of side reactions between sulfur cathode and carbonate solvents. [ABSTRACT FROM AUTHOR]

An efficient ORR/OER catalyst was developed by anchoring highly dispersed bimetallic PdM (M = Fe, Co, Ni) alloy nanoparticles on nitrogen-doped reduced graphene oxide (N-rGO). This new type of catalyst exhibited excellent ORR/OER activity, and the addition of transition metals also significantly improved catalytic stability, with the catalyst containing Fe (PdFe/N-rGO) exhibiting the best stability. A battery using this PdFe/N-rGO catalyst was capable of long-term stable cycling for 400 cycles (2000 h) with a limited capacity of 1000 mAh g −1 at 400 mA g −1 , which was much longer than a battery with Pd/N-rGO as the catalyst (only 80 cycles, 400 h). We attribute the high performance of these catalysts to the high surface area of N-rGO, the anchoring of highly dispersed Pd alloy nanoparticles, and the prevention of Pd alloy nanoparticle aggregation and dissolution by the presence of the transition metals. [ABSTRACT FROM AUTHOR]

Poly (ε-caprolactone) (PCL) is an attractive polymer electrolyte material due to its ultralow glass transition temperature, high dielectric constant as well as excellent electrochemical stability, but its practical application has been greatly hindered due to the low ionic conductivity induced by the semi-crystalline structure. Herein, we elaborately modify PCL with chitosan (CS) to obtain an amorphous PCL-CS composite membrane, and develop a fast Li+ conducting quasi-solid polymer electrolyte (QPE) with lithium bis(trifluoro methane sulphonyl)imide (LiTFSI) and merely 10 wt% plasticizer. The optimized QPE with 50 wt% LiTFSI exhibits an ionic conductivity of 7.7 × 10−4 S cm−1, which is the highest among PCL-based polymer electrolyte. Fourier Transform Infrared spectroscopy and Raman spectra reveal that Li+ conducting via the solvation of partial plasticizer as well as contacted ionic clusters. In addition, its excellent stability and compatibility are validated by the integrated symmetric Li//Li cell that exhibits an ultra-long cycling for over 1850 h with no Li dendrite formation. [Display omitted] • A totally amorphous polymer framework has been designed. • A higher ionic conductivity than reported PCL based polymer electrolyte. • Li ion is efficiently conducted via dual pathways. [ABSTRACT FROM AUTHOR]

Electrode/electrolyte contact failure caused by thick dead Li and SEI layer is principally responsible for the low utilization of lithium metal anode. The key to opening this lock is designing a host with fast mass transfer to promote uniform deposition of lithium to reduce the repeated SEI growth and dead Li production. Herein, an allocatable container constructed with porous MXene (Ti 3 C 2 T x) and carbon nanofibers is proposed for constraining Li deposition behavior. Multiphysics finite elemental analysis and SEM confirm the fast mass transfer ability and good deposition behavior of MXene foam. The benefit of this allocatable container is further confirmed by the symmetric cells, with lifetime of 1400 h at 1 mA cm−2, 1 mAh cm−2 and 200 h at 5 mA cm−2, 5 mAh cm−2. Morphology after cycle displays that the composite anode makes the utmost utilization of lithium metal. Moreover, full-cell armed with this composite Li anode and LiFePO 4 cathode exhibits galvanostatic charge/discharge performance with 510 cycles at 2C and 100 cycles at 4C (1C = 170 mA g−1). This work sheds light on reasonable Li metal container design, highlights the importance of high Li utilization and puts the practical usage of Li metal battery one more step forward. [Display omitted] • MXene foam was constructed by porous MXene and carbon nanofibers. • Porous structure of MXene foam improves mass transfer ability. • MXene foam has good deposition behavior and suitable thickness of Li. • The composite anode achieved a high utilization of lithium metal. [ABSTRACT FROM AUTHOR]

The parasitic side reaction between the electrolyte and the lithium metal (Li0) forms an unstable heterogeneous interphase, causing the poor reversibility of Li plating/stripping. The rational design of protection layer on Li0 anode is imperative to inhibit side reactions and achieve fast Li + transport on the Li0/electrolyte interface. Herein, by firstly coordinating the bis(fluorosulfonyl)imide anion (FSI−) to the protection layer, a layer consisting of 2D ionic vinylene-linked covalent organic frameworks (ivCOF-FSI) is proposed to stabilize the Li0/electrolyte interface. As demonstrated theoretically and experimentally, the triazine group in the cationic framework is identified to promote Li+ de-solvation process while partial FSI− prefers to form LiF-rich interphase. Attributed to these superiorities, the ivCOF-FSI layer endows the Li0/electrolyte interface with high reversibility in carbonate-based electrolytes by simultaneously suppressing the side effect and achieving rapid Li+ transfer. Combined with the high stability of solid-liquid interface, the LiFePO 4 full cells with ivCOF-FSI/Li anode display enhanced cyclability under a high cathode loading of 9.4 mg cm−2 and a low negative/positive capacity ratio of 5. This work provides a novel route for stabilizing the interfacial chemistry of solid-liquid interface, aiming to pave the way for the next-generation high-energy-density batteries. [Display omitted] • An ionic COFs (ivCOF-FSI) is proposed for stabilizing the Li0/electrolyte interface. • The FSI− is coordinated into the protection layer to form LiF-rich interphase. • The triazine group in the framework boosts the Li + de-solvation process. • The Li||Cu cell shows a high CE Avg. of 99.2% for over 390 cycles. • The LFP cells display enhanced cyclability under a high cathode mass loading. [ABSTRACT FROM AUTHOR]

Ni, Mo co-doped LiMn 2 O 4 cathode materials for lithium-ion batteries were prepared using a high-temperature solid-state method. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM),and electrochemical impedance spectroscopy. The original material’s performance was significantly enhanced by co-doping. The sample with optimal composition, LiNi 0.03 Mo 0.01 Mn 1.96 O 4 , had a discharge capacity at1C of 114 mAhg −1 , which was 8.6% higher than that of undoped LiMn 2 O 4 . Importantly, this doped material exhibited significantly improved stability: after 300 charge–discharge cycles at 1C, its capacity retention was 91.2%, whereas the capacity retention of the undoped LiMn 2 O 4 was only 61.9% after 300 cycles. SEM images and XRD patterns showed no obvious morphological changes in the co-doped material after cycling, implying that it had high structural stability. We suggest that this material’s significantly improved electrochemical performance was probably caused by reduced Mn 3+ dissolution and decreased Li + intercalation and de-intercalation resistances. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide co-doped with nitrogen and fluorine (N–F/rGO) was successfully prepared by a simple one-step thermal annealing process using a mixture of graphene oxide and ammonium fluoride in an argon atmosphere. X-ray photoelectron spectroscopy demonstrated that the nitrogen and fluorine atoms were successfully doped into the rGO structure at atomic percentages of 2.51 and 0.74, respectively. Nitrogen adsorption–desorption measurement revealed that the as-prepared N–F/rGO has a high surface area (412 m 2 g −1 ) with numerous slit-shaped pores (1.60 cm 3 g −1 ). The electrocatalytic activity of N–F/rGO for oxygen reduction reaction was found to be higher than that of rGO doped only with nitrogen (N/rGO); in fact, it was comparable to the activity of conventional commercial Pt/C in an alkaline electrolyte. In addition, the catalyst exhibited excellent long-term stability/durability, good methanol tolerance, and high selectivity for the four-electron transfer pathway. A possible mechanism is suggested for the improvement conferred by fluorine. [ABSTRACT FROM AUTHOR]

A high-performance self-humidifying membrane electrode assembly (MEA) was prepared by inserting hygroscopic microcrystalline cellulose (MCC) between the gas diffusion layer (GDL) and the catalyst layer (CL). At low humidity, the MEA exhibited good self-humidification, including high output and good stability. With our optimal MEA, in which the MCC loading was ca. 0.5 mg cm −2 , the current density at 0.6 V reached 1100 mA cm −2 and the maximum power density was 751 mW cm −2 , at a relative humidity (RH) of 30% for both anode and cathode gases and a cell temperature of 70 °C; the performance was comparable to that of a MEA prepared without added MCC and operated at 100% RH. Further, after 24 h of operation at low humidity and 0.6 V, the MEA's current density decreased by only 9.1%, compared with the 60% decline experienced by the MEA without MCC after 3 h under the same conditions, demonstrating the former's good self-humidification stability. When we attempted to insert the MCC layer elsewhere, including between the membrane and the anode CL, we found that inserting it between the GDL and the anode CL yielded the best performance. The high self-humidification performance of this MEA is attributable to the strong wettability and water-retention capacity of MCC. The MCC layer between the GDL and the anode CL ensured the latter would remain sufficiently wet and accelerated hydrogen activation and proton transfer, resulting in the MEA having high self-humidification under conditions of low humidity and high cell temperature. [ABSTRACT FROM AUTHOR]

We designed a novel aqueous rechargeable lithium battery with LiFePO 4 /C (LFP) and LiMn 2 O 4 /C (LMO) as the anode and cathode, respectively; then investigated the battery in Li 2 SO 4 aqueous electrolyte. We also studied the electrochemical behavior of LFP in aqueous electrolyte using cyclic voltammetry (CV). The material exhibited excellent electrochemical performance in the aqueous electrolyte, including good oxidation/reduction reversibility and cycling stability; almost no decays were observable after 200CV cycles. The diffusion coefficients of Li ions through the interface between the liquid electrolyte and the solid LiFePO 4 in terms of intercalation and deintercalation were 1.22 × 10 −14 and 9.97 × 10 −15 cm 2 /s, respectively. The material could be completely intercalated/deintercalated with Li ions in the aqueous electrolyte, indicating the excellent performance of LFP in an aqueous solution. Further, an aqueous rechargeable lithium battery (ARLB), which we fabricated using LFP as the anode and LMO as the cathode, also exhibited quite good performance in aqueous Li 2 SO 4 solution: after 1,000 charge–discharge cycles at 2 C, the capacity loss was less than 30%, indicating that this type of ARLB has excellent cycling stability and may be promising for future research and application. [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]

We synthesize a platinum monolayer core-shell catalyst with a ternary alloy nanoparticle core of Pd, Ir, and Ni. A Pt monolayer is deposited on carbon-supported PdIrNi nanoparticles using an underpotential deposition method, in which a copper monolayer is applied to the ternary nanoparticles; this is followed by the galvanic displacement of Cu with Pt to generate a Pt monolayer on the surface of the core. The core-shell Pd1Ir1Ni2@Pt/C catalyst exhibits excellent oxygen reduction reaction activity, yielding a mass activity significantly higher than that of Pt monolayer catalysts containing PdIr or PdNi nanoparticles as cores and four times higher than that of a commercial Pt/C electrocatalyst. In 0.1 M HClO4, the half-wave potential reaches 0.91 V, about 30 mV higher than that of Pt/C. We verify the structure and composition of the carbon-supported PdIrNi nanoparticles using X-ray powder diffraction, X-ray photoelectron spectroscopy, thermogravimetry, transmission electron microscopy, and energy dispersive X-ray spectrometry, and we perform a stability test that confirms the excellent stability of our core-shell catalyst. We suggest that the porous structure resulting from the dissolution of Ni in the alloy nanoparticles may be the main reason for the catalyst’s enhanced performance. [ABSTRACT FROM AUTHOR]

A high-performance PdRu bimetallic catalyst supported on mesoporous silica nanoparticles (MSN), PdRu/MSN, was prepared by a facile impregnation–hydrogen reduction method. It was found that PdRu/MSN showed 5 times higher activity than that of Pd/MSN towards the liquid-phase hydrogenation of phenol. The catalysts were characterized comprehensively by multiple techniques, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and hydrogen temperature program reduction (TPR). It was revealed that adding Ru could effectively improve the Pd dispersion and promote the electronic interaction between the Pd and Ru, both of which contribute to enhancing the catalytic activity. [ABSTRACT FROM AUTHOR]

Highlights: [•] Doped carbon catalyst Fe/oPD–Mela was prepared by pyrolyzing a hybrid precursor. [•] The catalyst shows graphene-like structure with high surface area up to 384m2 g−1. [•] The catalyst exhibits superior ORR activity to commercial Pt/C in alkaline medium. [•] The high performance of the catalyst may be caused by its high active N content. [•] ORR reaction changed from the 2e− process to the 4e− process by adding melamine. [Copyright &y& Elsevier]

Pd@Pt nanoparticles with a three-dimensional (3D) nanospherical shape have been prepared using a two-step approach in which the Pd nanospheres are synthesized controllably by a solvothermal method, and then a Pt monolayer is deposited on the Pd nanospheres using an underpotential deposition process. We systematically investigate (i) the influences of temperature and additive on the morphology of the Pd nanoparticles and (ii) the electrochemical activity of Pd@Pt for the oxygen reduction reaction (ORR). The Pd@Pt nanoparticles exhibit enhanced activity towards the ORR. The mass activity of Pt in the Pd@Pt nanospheres (1.03 A mgPt −1 ) is 3.3 times higher than that of commercial Pt/C (0.24 A mgPt −1 ). The catalyst enhanced activity may result from the 3D structure of the Pd nanospheres and the monolayer dispersion of Pt on the surface of the nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: Ultra-low Pt loading membrane electrode assemblies (ULP MEAs) are prepared through in situ construction of core–shell Ir@Pt nanoparticles (Ir/Vulcan XC-72R as the core) on the surface of an electrode via a pulse electrochemical deposition (PED) approach. The core material is coated on a membrane with a conventional catalyst-coated membrane process prior to the deposition of the shell metal (Pt in this case). The ULP MEAs are characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The effects of a number of preparation parameters on cell performance are investigated in detail. The performance of the ULP MEA, in which the anode loadings of Pt and metals are ∼0.012 mg cm−2 and 0.044 mg cm−2(0.012 mg cm−2 Pt + 0.032 mg cm−2 Ir) respectively, is found to be competitive with that of an MEA prepared with an anode Pt loading of 0.1 mg cm−2 (commercial Pt/C catalyst from Johnson Matthey), manifesting the solid advantage of this in situ PED method. [Copyright &y& Elsevier]

Abstract: High-performance heteroatom-doped carbon catalysts with large surface areas were prepared by pyrolyzing nanorod precursors that had been synthesized by polymerizing a mixture of aniline (An) and β-naphthalene sulfonic acid (NSA). The catalysts were characterized by scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, N2 adsorption/desorption isotherms, and elemental analysis. We intensively investigated how the catalysts’ structure and catalytic performance were affected by (i) the ratio of NSA to An and (ii) the addition of Fe. The catalysts retained their nanorod morphology after pyrolysis. The optimal NSA/An ratio was 3/2 and the optimal Fe content was 3wt%. The catalysts showed excellent activity toward oxygen reduction in an acidic medium, with the onset potential, half-wave potential, and limiting current density values reaching 0.86, 0.73V (vs. reversible hydrogen electrode), and 5.28mAcm−2, respectively. We suggest that the catalysts’ high performance may be due to the co-doping effects of nitrogen, sulfur, and iron, as well as the large surface area created by the nanorod structures. [Copyright &y& Elsevier]

A high voltage cathode material, LiNi0.5Mn1.5O4, is synthesized with a two-step approach, in which the nickel–manganese oxalate precipitate is firstly obtained by adding oxalic acid to the solution of nickel and manganese ions precursors, followed by calcining the oxalates to obtain spinel nickel–manganese oxide, incorporating lithium ions with ball milling and calcining at 900 °C for 15 h. The materials are characterized with TG, XRD, SEM, BET and FTIR; it is revealed that both nickel–manganese oxide and final LiNi0.5Mn1.5O4 have well defined spinel structure. The LiNi0.5Mn1.5O4 spinel materials exhibit high capacities and good cyclic stability, the capacity of the materials is in the range from 126 to 136 mAh −1, depending on the calcining temperatures. The sample calcined at an optimal temperature of 900 °C exhibits best performance, the capacity is high up to 136 mAh g−1 at tenth cycle and the capacity retention after 50 cycles is 93%. For the sample prepared by mixing and milling oxalate with lithium salt, the discharge capacity is only 115 mAh g−1. We suggest that the spinel oxide derived from oxalate may play an important role for the high performance and high stability of the final cathode materials. [ABSTRACT FROM AUTHOR]

Abstract: A novel self-humidifying membrane electrode assembly (MEA) has been successfully prepared by adding both a hydrophilic organic polymer (polyvinyl alcohol, PVA) and an inorganic oxide (silica) to the anode catalyst layer. This MEA shows excellent self-humidification performance under low-humidity conditions. A sample containing 3 wt.% PVA and 3 wt.% silica in the anode catalyst layer achieves a current density as high as 1100 mA cm−2 at 0.6 V, and the highest peak power density is 780 mW cm−2, operating at 60 °C and 15% relative humidity for both anode and cathode. The sample also shows excellent stability at low-humidity: after 30 h of continuous operation under the same conditions, the current density decreases just slightly, from 1100 mA cm−2 to ca. 900 mA cm−2, whereas with MEAs to which only PVA or silica alone had been added, the current densities after 30 h is just 700 mA cm−2 and 800 mA cm−2, respectively. The improved self-humidification performance can be attributed to the synergistic effect of two hygroscopic materials in the anode catalyst layer. [Copyright &y& Elsevier]

Highlights: [•] Mesoporous silica supported Pd-promoted gold catalyst was prepared. [•] Low Pd/Au atomic ratio of 0.05/1 can effectively decrease the gold particles size. [•] Pd0.2Au shows 8 and 3 times higher activity than the Au/MSN and Pd/MSN respectively. [•] Catalysts were characterized by XRD, N2 sorption, DRUV-vis, TPR, XPS and TEM. [Copyright &y& Elsevier]

Lithium–sulfur batteries (LSBs) are considered one of the most promising candidates for next-generation energy storage owing to their large energy capacity. Tremendous effort has been devoted to overcoming the inherent problems of LSBs to facilitate their commercialization, such as polysulfide shuttling and dendritic lithium growth. Pouch cells present additional challenges for LSBs as they require greater electrode active material utilization, a lower electrolyte–sulfur ratio, and more mechanically robust electrode architectures to ensure long-term cycling stability. In this review, the critical challenges facing practical Li–S pouch cells that dictate their energy density and long-term cyclability are summarized. Strategies and perspectives for every major pouch cell component—cathode/anode active materials and electrode construction, separator design, and electrolyte—are discussed with emphasis placed on approaches aimed at improving the reversible electrochemical conversion of sulfur and lithium anode protection for high-energy Li–S pouch cells. [ABSTRACT FROM AUTHOR]