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A class of imprintable, bendable, and shape-conformable polymer electrolyte with excellent electrochemical performance in a lithium battery system is reported. The material consists of a UV-cured polymer matrix, high-boiling point liquid electrolyte, and Al2 O3 nanoparticles, formulated for use in lithium-ion batteries with 3D-structured electrodes or flexible characteristics. The unique structural design and well-tuned rheological characteristics of the UV-curable electrolyte mixture, in combination with direct UV-assisted nanoimprint lithography, allow the successful fabrication of polymer electrolytes in geometries not accessible with conventional materials., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Current state‐of‐the‐art Li batteries use single‐phase electrolytes; however, these electrolytes often encounter difficulty in simultaneously fulfilling the nonidentical electrochemical requirements of cathodes and anodes. Here, a class of immiscible binary liquid electrolyte (BLE) is designed by starving free solvent molecules. Based on their electrochemical stability window, 1,2‐dimethoxyethane (DME) and succinonitrile (SN) are selected as model solvents for Li‐metal anodes and LiNi0.8Co0.1Mn0.1 (NCM811) cathodes, respectively. Li bis(fluorosulfonyl)imide (LiFSI), which promotes Li+ solvation (i.e., reduces free solvents), enables the phase separation of the miscible solvent mixture (SN−DME), and an increase in its concentration strengthens the coordination of Li+−FSI− in the solvation sheath, thus yielding (anion‐derived) fluorine‐rich electrode–electrolyte interphases. The resulting BLE allows 4.4 V Li‐metal full cells to exhibit a stable capacity retention under a constrained cell condition (Li (20 µm, 4.1 mAh cm−2)||NCM811 (3.8 mAh cm−2), N (negative)/P (positive) capacity ratio = 1.08), which exceed those of previously reported binary liquid electrolytes. [ABSTRACT FROM AUTHOR]

Despite their potential as post lithium‐ion batteries, solid‐state Li‐metal batteries are struggling with insufficient electrochemical sustainability and ambient operation limitations. These challenges mainly stem from lack of reliable solid‐state electrolytes. Here, a new class of single‐ion conducting quasi‐solid‐state soft electrolyte (SICSE) for practical semi‐solid Li‐metal batteries (SSLMBs) is demonstrated. The SICSE consists of an ion‐rectifying compliant skeleton and a nonflammable coordinated electrolyte. Rheology‐tuned SICSE pastes, in combination with UV curing‐assisted multistage printing, allow fabrication of seamlessly integrated SSLMBs (composed of a Li metal anode and LiNi0.8Co0.1Mn0.1 cathode) without undergoing high‐pressure/high‐temperature manufacturing steps. The single‐ion conducting capability of the SICSE plays a viable role in stabilizing the interfaces with the electrodes. The resulting SSLMB full cell exhibits stable cycling performance and bipolar configurations with tunable voltages and high gravimetric/volumetric energy densities (476 Wh kgcell−1/1102 Wh Lcell−1 at four‐stacked cells with 16.656 V) under ambient operating conditions, along with low‐temperature performance, mechanical foldability, and nonflammability. [ABSTRACT FROM AUTHOR]

The discovery of a reliable electrolyte system remains one of the key challenges for the development of advanced lithium–oxygen batteries. To date, no single electrolyte is verified to be stable and compatible with both the cathode (e.g., oxygen radicals, lithium peroxide, etc.) and anode (lithium metal) for lithium–oxygen batteries. In this work, a novel liquid‐based Janus electrolyte system consisting of two different immiscible liquid phases is proposed and it is demonstrated that this system is remarkably effective in promoting the sustainable operation of redox‐mediated lithium–oxygen batteries. The liquid‐based Janus electrolyte is rationally designed by considering its compatibility with the lithium–oxygen cell environment, the solubility difference of target soluble species, and the mutual immiscibility of the two liquid phases. By combining spectral characterization, a phase‐separation experiment, and in situ observation of the electrochemical cell, it is revealed that the liquid‐based Janus electrolyte suppresses the migration of redox mediators from one liquid phase to the other, thereby preventing the detrimental shuttle effect. The enhanced stability of redox mediation leads to improved cycling performance of the cell. The various combinations possible for the liquid‐based Janus electrolyte open a new unexplored pathway for the design of advanced electrolyte systems for lithium–oxygen batteries. [ABSTRACT FROM AUTHOR]

Conventional self‐charging systems are generally complicated and highly reliant on the availability of energy sources. Herein, a chemically self‐charging, flexible solid‐state zinc ion battery (ssZIB) based on a vanadium dioxide (VO2) cathode and a polyacrylamide‐chitin nanofiber (PAM‐ChNF) hydrogel electrolyte is developed. With a power density of 139.0 W kg‐1, the ssZIBs can deliver a high energy density of 231.9 Wh kg‐1. The superior electrochemical performance of the ssZIBs is attributed to the robust tunnel structure of the VO2 cathode and the entangled network of PAM‐ChNF electrolyte, which provide efficient pathways for ion diffusion. Impressively, the designed ssZIBs can be chemically self‐charged by the redox reaction between the cathode and oxygen in ambient conditions. After oxidation for 6 h in air, the ssZIBs manifest a high discharging capacity of 263.9 mAh g‐1 at 0.2 A g‐1, showing excellent self‐rechargeability. With the assistance of a small amount of acetic acid added to the hydrogel electrolyte, the galvanostatic discharging and chemical self‐charging cycles can reach 20. More importantly, such ssZIBs are able to operate well at chemical or/and galvanostatic charging hybrid modes, demonstrating superior reusability. This work brings a new prospect for designing flexible chemically self‐charging ssZIBs for portable self‐powered systems. [ABSTRACT FROM AUTHOR]

The excellent stability of sulfide solid electrolytes with solvate ionic liquids Li(triethylene glycol dimethyl ether)bis(trifluoromethanesulfonyl)imide (Li(G3)TFSI), and their application for high‐performance, all‐solid‐state lithium‐ion batteries are successfully demonstrated. The addition of a small amount of Li(G3)TFSI gives an alternative ionic pathway through normally poor solid–solid contacts, leading to a dramatic increase in LiFePO4 composite electrode capacity. [ABSTRACT FROM AUTHOR]

The combination of high-capacity anodes and high-voltage cathodes has garnered a great deal of attention in the pursuit of high-energy-density lithium-ion batteries. As a facile and scalable electrode-architecture strategy to achieve this goal, a direct one-pot decoration of high-capacity silicon (Si) anode materials and of high-voltage LiCoO2 (LCO) cathode materials is demonstrated with colloidal nanoparticles composed of electroconductive antimony-doped tin oxide (ATO). The unusual ATO nanoparticle shells enhance electronic conduction in the LCO and Si electrode materials and mitigate unwanted interfacial side reactions between the electrode materials and liquid electrolytes. The ATO-coated LCO materials (ATO-LCO) enable the construction of a high-mass-loading cathode and suppress the dissolution of cobalt and the generation of by-products during high-voltage cycling. In addition, the ATO-coated Si (ATO-Si) anodes exhibit highly stable capacity retention upon cycling. Integration of the high-voltage ATO-LCO cathode and high-capacity ATO-Si anode into a full cell configuration brings unprecedented improvements in the volumetric energy density and in the cycling performance compared to a commercialized cell system composed of LCO/graphite. [ABSTRACT FROM AUTHOR]

Abstract: A new approach enabling the target control of exothermic reaction between delithiated LiCoO2 and liquid electrolytes has been presented, which is based on the nano-encapsulation of LiCoO2 by cPVA (cyanoethyl polyvinylalcohol)-based gel polymer electrolytes. This novel morphology and the possible formation of coordinated complexes between the cyano (–CN) groups of cPVA and the cobalt cations of LiCoO2 are considered as key factors to significantly suppress the exothermic reaction in the delithiated LiCoO2. Such an improved thermal stability of the cPVA-modified LiCoO2 has led to a noticeable achievement in the hot-oven safety behavior of cells. Meanwhile, it was observed that both the excellent ionic conductivity of cPVA-based gel polymer electrolytes and the well-preserved porous structure of modified cathodes contribute to the satisfactory C-rate capability and the cyclability of cells. [Copyright &y& Elsevier]

Lithium‐sulfur (Li‐S) batteries have garnered considerable interest as a promising alternative to current state‐of‐the‐art Li‐ion batteries. However, the shuttle effect poses a formidable challenge to development of Li‐S batteries. Considering that all ions in electrolytes move through separators between electrodes, significant attention should be paid to separators to prevent the shuttle effect. Here, a new class of spiderweb‐mimicking, anion‐exchanging separators based on polyionic liquids ("spiderweb separators") is demonstrated to address the aforementioned issue. The spiderweb separator consists of sandwich‐type functional nanomats (top/bottom layers = multi‐walled carbon nanotube‐wrapped polyetherimide nanomats, middle layer = poly(1‐ethyl‐3‐methylimidazolium) bis(trifluoromethanesulfonyl)imide (PVIm[TFSI], polyionic liquid)/poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐HFP) nanomat) on polyethylene separator. The middle nanomat layer enables (discharge voltage‐dependent) reversible trap/release of polysulfides via an anion exchange reaction between TFSI−anions (from PVIm[TFSI]) and polysulfides. The top/bottom nanomat layers respectively act as an upper current collector and a blocking layer to prevent crossover of polysulfides to Li anodes. Driven by its unique morphology and chemical functionalities, the spiderweb separator prevents the shuttle effect while ensuring facile ion transport, leading to exceptional improvement in the electrochemical performance (capacity = 819 mAh g−1 and cycling retention = 72% (at 2.0 C/2.0 C) after 300 cycles) of Li‐S batteries. Spiderweb‐mimicking anion‐exchanging separators are presented as membrane‐driven strategy for the developing high‐performance Li–S batteries. The polyionic liquid (poly(1‐ethyl‐3‐methylimidazolium) bis(trifluoromethanesulfonyl)imide, (PVIm[TFSI]))–based nanomat in the spiderweb separator enables discharge voltage–dependent, reversible trap/release of polysulfides via an anion exchange reaction between TFSI− anions and polysulfides. Eventually, the spiderweb separator prevents the shuttle effect with ensuring facile ion transport. [ABSTRACT FROM AUTHOR]

Abstract: Evaporation-induced, close-packed silica (SiO2) nanoparticle-embedded polyethylene terephthalate (PET) nonwoven composite separator membranes (hereinafter, referred to as “NW-separators”) are fabricated for application in high-voltage/high-rate lithium-ion batteries. The heat-resistant PET nonwoven is employed as a physical support to suppress thermal shrinkage of the NW-separator. A distinctive characteristic of the NW-separator is the well-connected interstitial voids formed between compactly packed SiO2 nanoparticles adhered by polyvinylidene fluoride–hexafluoropropylene (PVdF–HFP) binders. This allows for the evolution of highly percolated, electrolyte-philic microporous architecture in the NW-separator. In comparison to a commercialized polyethylene (PE) separator, the NW-separator featuring the aforementioned structural uniqueness exhibits substantial improvements in porosity, air permeability, and electrolyte wettability, which contribute to the facile ionic transport and retarded growth of cell impedance during cycling. As a result, superior cell performance is obtained in the NW-separator. Notably, this advantageous effect of the NW-separator on cell performance becomes more pronounced at challenging charge/discharge conditions of high voltages (herein, 4.4V) and high current densities. [Copyright &y& Elsevier]

Abstract All-solid-state lithium-ion batteries (ASLBs) are receiving considerable attention due to their safety superiority and high energy density (achieved by bipolar configuration). Inorganic solid electrolytes are explored as a key-enabling material of the ASLBs. However, their critical challenges, including grain boundary resistance, interfacial instability with electrode materials and complicated processability, remain yet unresolved. Here, we demonstrate a new class of gel electrolyte with reversible thixotropic transformation and abuse tolerance as an effective and scalable approach to address the aforementioned longstanding issues. The gel electrolyte consists of (fluoropolymer/cellulose derivative) matrix and liquid electrolyte. The reversible thixotropic transformation is realized via sol-gel transition based on Coulombic interaction of the polymer matrix with liquid electrolyte. This unusual rheological feature allows the gel electrolyte to be printed in various forms. In addition, the gel electrolyte shows low crystallinity, thus playing a viable role in delivering high ionic conductivity. Based on understanding of rheological/electrochemical characteristics of the gel electrolyte, we fabricate a form factor-free pouch-type cell assembled with the gel electrolyte using sequential screen-printing process. The resultant cell shows exceptional safety upon exposure to various harsh abuse conditions, along with decent electrochemical performance. Highlights • A new class of gel electrolyte with reversible thixotropic property is demonstrated. • The gel electrolyte consists of (fluoropolymer/cellulose derivatives) and liquid electrolyte. • A form factor-free pouch-type cell can also be assembled with the gel electrolyte. [ABSTRACT FROM AUTHOR]

ESSs (Energy storage systems) for large-scale grid systems and next generation secondary battery systems require an ideal device that satisfies diverse properties such as a high energy density, high power density, low cost, and safe and reliable performance. In this study, we present a CUCap (cyclic ultracapacitor), which is comprised of two reservoirs and one flat flow capacitor cell with a cyclic continuous flow mode and independently tunable power rating and energy capacity. CUCap provides fast-charging and high capacity technology with a simple and practical design for high density and large-scale energy storage systems. The best performance appeared in slurry ratio (electrode to electrolyte) 1 to 7 with the total reservoir volume of 150 mL and the flow rate 300 ml/min, resulting in volumetric energy density, specific capacitance, and discharge time of 7.7 Wh L −1 , 14.2 F ml −1 , 100 min, respectively. Moreover, the slurry electrode of the CUCap cell had a maximum current density around 260 mA cm −2 which could possibly result in a fast-charging CUCap system. [ABSTRACT FROM AUTHOR]

Solid electrolytes are regarded as promising candidates replacing organic liquid electrolyte due to much enhanced safety, which is able to use lithium metal as an anode material for high energy system. Among several solid electroytes, garnet-type solid electrolyte has wide electrochemical window as well as high chemical stability and ionic conductivity at room temperature. However, from an assembled full cell's point of view, high interfacial resistance between electrode and solid electrolyte is a huge obstacle which should be overcome. Herein, we synthesize high ionic conductivy of Gallium-doped garnet-type solid electrolyte (Li6.25Ga0.25La3Zr2O12) having 1.2 mS cm-1 at room temperature and then applied gel polymer electrolyte into cathode by in situ gelation method for a full cell system. The interfacial resistance is reduced by about 260 times and rate capability from 0.05C to 1C was 80%, which is superior to a hybrid of liquid electrolyte and LGLZO cell system. Initial capacity retaines 89% even after 800 cycles at 0.5C. [Display omitted] • We synthesized high ionic conductivity of solid electrolyte having 1.2 mS cm−1. • Gel polymer electrolyte was applied by in situ gelation method for a cell system. • Gel electrolyte guaranteered ionic percolation at Interface. • Initial capacity was reversibly retained 89% even after 800 cycles at 0.5C. • Cell capacity was reversibly kept after 80 °C and 100 °C heat treatment. [ABSTRACT FROM AUTHOR]

Abstract: A novel approach for effectively dispersing SiO2 nanoparticles in a sulfonated poly(arylene ether sulfone) ionomer (SPAES) matrix has been demonstrated. It is based on the application of wet-type milling process. Compared to a conventional mixing process such as sonication, wet-type milling allowed noticeable improvements in SiO2 nanoparticle dispersion, owing to the intensive impact of collisions between milling beads and nanoparticles. In terms of nanoparticle dispersion, the influence of wet-type milling on the direct methanol fuel cells (DMFC) membrane performance such as proton conductivity, methanol permeability, and selectivity was examined and compared with sonication process. This study underlines that nanoparticle dispersion in the composite membranes is crucial in determining DMFC membrane performance and can be substantially improved by employing a novel mixing process, i.e. wet-type milling. [Copyright &y& Elsevier]