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Poly(ethylene oxide) (PEO)-based composite electrolytes (PCEs) are considered as promising candidates for next-generation lithium-metal batteries (LMBs) due to their high safety, easy fabrication, and good electrochemical stability. Here, we utilize operando grazing-incidence small-angle and wide-angle X-ray scattering to probe the correlation of electrochemically induced changes and the buried morphology and crystalline structure of the PCE. Results show that the two irreversible reactions, PEO-Li+ reduction and TFSI- decomposition, cause changes in the crystalline structure, array orientation, and morphology of the PCE. In addition, the reversible Li plating/stripping process alters the inner morphology, especially the PEO-LiTFSI domain radius and distance between PEO-LiTFSI domains, rather than causing crystalline structure and orientation changes. This work provides a new path to monitor a working battery in real time and to a detailed understanding of the Li+ diffusion mechanism, which is essential for developing highly transferable and interface-stable PCE-based LMBs.

The electrochemical performance and related mechanisms of NaNi 0.4 Fe 0.2 Mn 0.4 O 2 (NNFM) as symmetrical electrode for low-temperature ceramic fuel cells were investigated. After reduction in H 2 at elevated temperature, sodium compounds including NaOH molten salt are formed in the NNFM anode, which diffuses into the GDC electrolyte, creating a composite electrolyte of "GDC-sodium compounds" with high ionic conductivity. The ionic conductivity of the "GDC-sodium compounds" composite electrolyte generated in the cell with GDC/NNFM (weight ratio 8/2) composite as the electrolyte layer reached 0.116 S · cm−1 at 550 °C. The maximum power density of the cell with the "GDC-sodium compounds" composite electrolyte reaches 273 mW · cm−2 at 550 °C. The presence of molten salt in the sodium compounds enhances the electrolyte's ionic conductivity while also contributing to the filling of internal pores and ensuring effective fuel gas sealing. The formation of sodium compounds molten salt within the cell also significantly reduces the polarization resistance associated with the electrode reactions in the electrodes on both sides of the cell. • NaOH molten salt forms high-conductivity GDC-sodium composite at 550 °C. • GDC/NNFM electrolyte reaches 0.116 S cm⁻1 ionic conductivity at 550 °C. • Sodium molten salt improves sealing and reduces electrode polarization resistance. • NNFM content affects performance, showing an increase then decrease. [ABSTRACT FROM AUTHOR]

To utilize abundant solar energy, dye-sensitized solar cells (DSSCs) have attracted researchers' attention due to many reasons, such as low production costs, easy fabrication methods, low toxicity of the materials, and relatively high-power conversion efficiencies. The use of expensive metal-dye complexes, the lack of long-term stability due to the use of liquid electrolytes, and the use of rare and expensive Pt as the CE are the major drawbacks preventing the large-scale production of DSSCs. However, recent studies showed alternative materials can be used to enhance the DSSC performance. The unique properties of graphene make it an ideal additive to improve the functions of all three components of DSSCs. Graphene's high optical transmittance and electron mobility are suitable to improve transparent conducting substrates and nanostructured wide bandgap semiconductor layers of the photoelectrode. Graphene quantum dots have a wide absorption spectrum and thus can be used as photosensitizers. High catalytic activity, high electrical conductivity, high corrosion resistance, and a larger specific surface area make graphene and its composites suitable for making CEs. In addition, graphene has been used to improve composite electrolytes intended for DSSCs. Considering all these facts, this article reviews the recent developments and applications of graphene-based materials in photoelectrodes, electrolytes and CEs and the possible uses of graphene to improve DSSCs. [ABSTRACT FROM AUTHOR]

The intense research of lithium‐ion batteries has been motivated by their successful applications in mobile devices and electronic vehicles. The emerging of intelligent control in kinds of devices brings new requirements for battery systems. The high‐energy lithium batteries are expected to respond or react under different environmental conditions. In this work, a tri‐salt composite electrolyte is designed with a temperature switch function for intelligently temperature‐controlled lithium batteries. Specifically, the halide Li3YBr6 together with LiTFSI and LiNO3 works as active fillers in a low‐melting‐point polymer matrix (polyethyleneglycol dimethyl ether (PEGDME) and polyethylene oxide (PEO)), which is further filled into the pre‐lithiated alumina fiber skeleton. Above 60 °C, the composite electrolyte exists in the liquid state and fully contacts with the working electrodes on the liquid–solid interface, effectively minimizing the interfacial resistance and leading to high discharge capacity in the cell. The electrolyte is changed into a solid state below 30 °C so that the ionic conductivity is significantly reduced and the interface resistance is increased dramatically on the solid–solid interface. Therefore, by simply adjusting the temperature, the cell can be turned "ON" or "OFF" intentionally. This novel function of the composite electrolyte has enlightening significance in developing intelligently temperature‐controlled lithium batteries. [ABSTRACT FROM AUTHOR]

The "interface" between polymer and oxide within the polymer‐oxide composite electrolytes is widely acknowledged as a crucial factor influencing ionic conduction. However, a fundamental understanding of the precise composition and/or micro‐structure, and the ionic conduction mechanism at the complex interface has remained elusive, primarily due to a dearth of compelling experimental evidence. In this study, the intricate correlation between morphology and composition in composite electrolytes is discerned by leveraging advanced 1D and 2D exchange nuclear magnetic resonance spectroscopy (1D and 2D EXSY NMR) techniques. Notably, this research represents the inaugural elucidation of the microstructure of the interface. The findings underscore the pivotal role of the preparation conditions for polymer‐oxide composite electrolytes, particularly the solvent selection, in determining the formation of the interface structure. Direct insights into the lithium‐deficient surface of Li6.4La3Zr1.4Ta0.6O12 (LLZTO) are provided and elucidate the timescales of Li‐ion exchange processes among various components. Furthermore, a comprehensive investigation into the roles of individual components within the composite electrolyte on the Li‐ion conduction mechanism is conducted through the 6Li→7Li isotope tracer technique as a function of current density. [ABSTRACT FROM AUTHOR]

The ideal composite electrolyte for the pursued safe and high‐energy‐density lithium metal batteries (LMBs) is expected to demonstrate peculiarity of superior bulk conductivity, low interfacial resistances, and good compatibility against both Li‐metal anode and high‐voltage cathode. There is no composite electrolyte to synchronously meet all these requirements yet, and the battery performance is inhibited by the absence of effective electrolyte design. Here we report a unique "concentrated ionogel‐in‐ceramic" silanization composite electrolyte (SCE) and validate an electrolyte design strategy based on the coupling of high‐content silane‐conditioning garnet and concentrated ionogel that builds well‐percolated Li+ transport pathways and tackles the interface issues to respond all the aforementioned requirements. It is revealed that the silane conditioning enables the uniform dispersion of garnet nanoparticles at high content (70 wt%) and forms mixed‐lithiophobic‐conductive LiF‐Li3N solid electrolyte interphase. Notably, the yielding SCE delivers an ultrahigh ionic conductivity of 1.76 × 10−3 S cm−1 at 25 °C, an extremely low Li‐metal/electrolyte interfacial area‐specific resistance of 13 Ω cm2, and a distinctly excellent long‐term 1200 cycling without any capacity decay in 4.3 V Li||LiNi0.5Co0.2Mn0.3O2 (NCM523) quasi‐solid‐state LMB. This composite electrolyte design strategy can be extended to other quasi−/solid‐state LMBs. [ABSTRACT FROM AUTHOR]

A disordered sodium borohydride (NaBH4) environment to facilitate Na+ mobility was achieved by partially hydrolyzing NaBH4 and this significantly improved Na+ ionic conductivity to 10−3 S cm−1 at 75 °C. The reaction rate of NaBH4 self-hydrolysis, however, is determined by several parameters, including the reaction temperature, the molar ratio between NaBH4 and H2O, and the pH value; but these factors are hard to control. In this paper, poly(ethylene oxide) (PEO), capable of retaining H2O through hydrogen bonding, was used in an attempt to better control the amount of H2O available for NaBH4 self-hydrolysis. This strategy led to the ionic conductivity of 1.6 × 10−3 S cm−1 at 45 °C with a Na+ transference number of 0.54. The amorphous nature of the PEO matrix in hydrolyzed NaBH4 is also believed to provide a conduction path for fast Na+ conduction. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Chinese Society of Rare Earths is the property of Editorial Department of Journal of the Chinese Society of Rare Earths and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the current challenging energy storage and conversion landscape, solid‐state lithium metal batteries with high energy conversion efficiency, high energy density, and high safety stand out. Due to the limitations of material properties, it is difficult to achieve the ideal requirements of solid electrolytes with a single‐phase electrolyte. A composite solid electrolyte is composed of two or more different materials. Composite electrolytes can simultaneously offer the advantages of multiple materials. Through different composite methods, the merits of various materials can be incorporated into the most essential part of the battery in a specific form. Currently, more and more researchers are focusing on composite methods for combining components in composite electrolytes. The ion transport capacity, interface stability, machinability, and safety of electrolytes can be significantly improved by selecting appropriate composite methods. This review summarizes the composite methods used for the components of composite electrolytes, such as filler blending, embedded framework, and multilayer bonding. It also discusses the future development trends of all‐solid‐state lithium batteries (ASSLBs). [ABSTRACT FROM AUTHOR]

All‐solid‐state batteries have the potential for enhanced safety and capacity over conventional lithium ion batteries, and are anticipated to dominate the energy storage industry. As such, strategies to enable recycling of the individual components are crucial to minimize waste and prevent health and environmental harm. Here, we use cold sintering to reprocess solid‐state composite electrolytes, specifically Mg and Sr doped Li7La3Zr2O12 with polypropylene carbonate (PPC) and lithium perchlorate (LLZO−PPC−LiClO4). The low sintering temperature allows co‐sintering of ceramics, polymers and lithium salts, leading to re‐densification of the composite structures with reprocessing. Reprocessed LLZO−PPC−LiClO4 exhibits densified microstructures with ionic conductivities exceeding 10−4 S/cm at room temperature after 5 recycling cycles. All‐solid‐state lithium batteries fabricated with reprocessed electrolytes exhibit a high discharge capacity of 168 mA h g−1 at 0.1 C, and retention of performance at 0.2 C for over 100 cycles. Life cycle assessment (LCA) suggests that recycled electrolytes outperforms the pristine electrolyte process in all environmental impact categories, highlighting cold sintering as a promising technology for recycling electrolytes. [ABSTRACT FROM AUTHOR]

Solid polymer and perovskite-type ceramic electrolytes have both shown promise in advancing solid-state lithium metal batteries. Despite their favorable interfacial stability against lithium metal, polymer electrolytes face issues due to their low ionic conductivity and poor mechanical strength. Highly conductive and mechanically robust ceramics, on the other hand, cannot physically remain in contact with redox-active particles that expand and contract during charge-discharge cycles unless excessive pressures are used. To overcome the disadvantages of each material, polymer-ceramic composites can be formed; however, depletion interactions will always lead to aggregation of the ceramic particles if a homopolymer above its melting temperature is used. In this study, we incorporate Li0.33La0.56TiO3 (LLTO) nanoparticles into a block copolymer, polystyrene-b-poly (ethylene oxide) (SEO), to develop a polymer-composite electrolyte (SEO-LLTO). TEMs of the same nanoparticles in polyethylene oxide (PEO) show highly aggregated particles whereas a significant fraction of the nanoparticles are dispersed within the PEO-rich lamellae of the SEO-LLTO electrolyte. We use synchrotron hard x-ray microtomography to study the cell failure and interfacial stability of SEO-LLTO in cycled lithium-lithium symmetric cells. Three-dimensional tomograms reveal the formation of large globular lithium structures in the vicinity of the LLTO aggregates. Encasing the SEO-LLTO between layers of SEO to form a "sandwich" electrolyte, we prevent direct contact of LLTO with lithium metal, which allows for the passage of seven-fold higher current densities without signatures of lithium deposition around LLTO. We posit that eliminating particle clustering and direct contact of LLTO and lithium metal through dry processing techniques is crucial to enabling composite electrolytes.

The potential application of plasma spraying in the preparation of ceramic electrolyte for porous metal-supported solid oxide fuel cells (SOFCs) is highlighted by its ability to eliminate the need for a high-temperature sintering process. However, the challenge of achieving highly dense electrolytes through plasma spraying remains to be addressed. In this study, a novel electrolyte for porous metal-supported SOFCs (PMS-SOFCs) is developed. This involved the preparation of a highly dense structure of gadolinium-doped ceria (GDC)-lanthanum strontium gallium magnesium oxide (LSGM) composite coating using plasma spraying under atmospheric conditions. The composite electrolyte is prepared using atmospheric plasma spraying (APS). The addition of the low-melting-point LSGM phase enhanced the microstructural densification of the GDC-based composite coating and diminished electron loss in a reducing atmosphere, thereby improving the cell's open-circuit voltage. At 36 kW plasma arc power, the single cell with composite electrolyte exhibited a maximum power density of 371 mw/cm2 at 750 °C and achieved the highest open-circuit voltage (1.03 V) at 600 °C. Moreover, the open-circuit voltage remained stable over a 100-h test. These findings suggest that using APS to deposit a composite electrolyte with added low-melting-point secondary phases presents a promising approach for achieving relatively high OCV in PMS-SOFCs based on cerium oxide electrolytes. [Display omitted] • Bulk-like composite electrolyte directly fabricated by atmospheric plasma spray. • OCV can reach 1.03V at 600 °C for ceria-based composite electrolyte. • LSGM splats effectively blocked the electron conducting in GDC deposits. • Low melting point LSGM could enhance the interface bonding of plasma-sprayed GDC electrolyte. [ABSTRACT FROM AUTHOR]

Inferior air stability is a primary barrier for large‐scale applications of garnet electrolytes in energy storage systems. Herein, a deeply hydrated hydrogarnet electrolyte generated by a simple ion‐exchange‐induced phase transition from conventional garnet, realizing a record‐long air stability of more than two years when exposed to ambient air is proposed. Benefited from the elimination of air‐sensitive lithium ions at 96 h/48e sites and unobstructed lithium conduction path along tetragonal sites (12a) and vacancies (12b), the hydrogarnet electrolyte exhibits intrinsic air stability and comparable ion conductivity to that of traditional garnet. Moreover, the unique properties of hydrogarnet pave the way for a brand‐new aqueous route to prepare lithium metal stable composite electrolyte on a large‐scale, with high ionic conductivity (8.04 × 10−4 S cm−1), wide electrochemical windows (4.95 V), and a high lithium transference number (0.43). When applied in solid‐state lithium batteries (SSLBs), the batteries present impressive capacity and cycle life (164 mAh g−1 with capacity retention of 89.6% after 180 cycles at 1.0C under 50 °C). This work not only designs a new sort of hydrogarnet electrolyte, which is stable to both air and lithium metal but also provides an eco‐friendly and large‐scale fabrication route for SSLBs. [ABSTRACT FROM AUTHOR]

Seeking for composite electrolytes reinforced all-solid-state sodium ion batteries with superior long lifespan and rate performance remains a great challenge. Here, a unique strategy to tailor the architecture of composite electrolyte via inserting polymer chains into a small quantity of sulfate sodium grafted C48H28O32Zr6 (UIOSNa) is proposed. The intimate contact between polymer segments and UIOSNa with limited pore size facilitates the anion immobilization of sodium salts and reduction of polymer crystallinity, thereby providing rapid ion conduction and reducing the adverse effect caused by the immigration of anions. The grafting of −SO3Na groups on fillers allows the free movement of more sodium ions to further improve t Na + and ionic conductivity. Consequently, even with the low content of UIOSNa fillers, a high ionic conductivity of 6.62 × 10−4 S·cm−1 at 60 °C and a transference number of 0.67 for the special designed composite electrolyte are achieved. The assembled all-solid-state sodium cell exhibits a remarkable rate performance for 500 cycles with 95.96% capacity retention at a high current rate of 4 C. The corresponding pouch cell can stably work for 1000 cycles with 97.03% capacity retention at 1 C, which is superior to most of the reported composite electrolytes in the literature. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Xinyang Normal University Natural Science Edition is the property of Journal of Xinyang Normal University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights The poly(1,3-dioxolane) (PDOL) electrolyte demonstrates promising potential for practical application due to its advantages in in-situ polymerization process, high ionic conductivity, and long cycle life. This review focuses on the polymerization mechanism, composite innovation, and application of PDOL electrolytes. This review provides a comprehensive summary of the challenges associated with the PDOL electrolyte and makes forward-looking recommendations.

Composite electrolytes of sodium carbonate and samarium doped ceria (SDC-Na 2 CO 3) provide outstanding proton conductivity between 300 °C and 650 °C, which is extremely sensitive to the synthesis procedure and to the amount and crystallinity of the carbonate phase. Here, the role of sodium carbonate in establishing the composite conductivity is explored in relation to chemical-structural and morphological characterization methods (ICP, XRD, SEM, TEM). A coprecipitation route is properly optimized to prepare composites with <50 nm SDC particles with sodium carbonate in different amounts. The amount of carbonate, carefully quantified via elemental analysis, strongly influences the proton conductivity, while the oxygen ion conductivity is much less affected. The formulation with 27 wt% of carbonate prepared through a single-step synthesis shows the best performance, with 2.27*10−2 S cm−1 proton conductivity in dry hydrogen (4 % H 2 in N 2) at 600 °C, and 1.73*10−2 S cm−1 oxygen ion conductivity in air. Interestingly, an SDC-Na 2 CO 3 composite containing the same salt amount but produced via a double-step procedure showed lower conductivity, confirming the pivotal role of the preparation methodology in defining the composite proton conductivity. In addition, humidification is found to depress H+ conductivity, thus indicating that the preferential charge transport mechanism does not involve hydroxides, in contrast to conventional protonic ceramics. Overall, the investigation reveals a strong dependence of the composite proton conductivity on the density of the carbonate/SDC interfaces and the crystallinity of the carbonate. [Display omitted] • Nanocomposites of Na 2 CO 3 and Sm 0.2 Ce 0.8 O 1.9 (SDC) are synthesized by coprecipitation. • SDC nanoparticles with Na 2 CO 3 shell are obtained with a consistent synthesis protocol. • 27 % wt Na 2 CO 3 leads to optimal proton conductivity between 400 °C and 650 °C. • 1.68 10−2 S/cm H+ conductivity and 1.73 10−3 S/cm O2− conductivity are found at 600 °C. • Dry H 2 feed boosts proton conductivity, while humidification reveals detrimental. [ABSTRACT FROM AUTHOR]

The fluorite-structured oxygen ion conductor gadolinium-doped cerium oxide (GDC) is preferred as an electrolyte for low- and medium-temperature solid oxide fuel cells over yttria-stabilized zirconia (YSZ). However, GDC requires a higher sintering temperature which limits its application. To decrease its sintering temperature and enhance its conductivity at low and medium temperatures, a novel (Dy 0.20 Zr 0.05 Bi 0.75) 2 O 3-δ - Gd 0.10 Ce 0.90 O 2-δ (xDZSB-GDC, x = 1,2,3,4,5, and10 wt%) nanocomposite is designed and prepared by solid-phase method. Microstructure and electrochemical characteristics of the DZSB-GDC composite are studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and alternating current (AC) impedance spectroscopy. DZSB effectively promotes the densification of the GDC electrolyte and reduces GDC's grain-boundary impedance. Theuniform distribution of DZSB around the GDC interface provided channels for ion transfer. Compared to the GDC electrolyte (1.30 × 10−3 S cm−1), the conductivity of 10 DZSB-GDC is six times higher at 550 °C (8.30 × 10−3 S cm−1). DZSB at low oxygen partial pressure efficiently inhibits the electronic conduction of GDC and boosts the open-circuit voltage of the single cell. At 750 °C, the maximum output power of a 10DZSB-GDC electrolyte-supported single cell is 364 mWcm−2, greater than 1.75 times the power density of a GDC-supported cell. These findings indicate thatDZSB-GDC is a promising electrolyte material for solid oxide fuel cells. [Display omitted] [ABSTRACT FROM AUTHOR]

Previous studies have found that in ceramic fuel cells using Ni 0·8 Co 0·15 Al 0·05 LiO 2 (NCAL) as the electrode, lithium compounds such as LiOH generated by reduction of NCAL anode by H 2 diffuse into oxide electrolyte membranes such as Gd 0.1 Ce 0·9 O 2 (GDC), and the "GDC-lithium compounds" composite electrolyte formed online is an excellent proton conductor. In this paper, the low-temperature electrolysis performance of proton conductor type solid oxide electrolysis cell (P-SOEC) with GDC as electrolyte and NCAL as electrode for direct electrochemical conversion of H 2 O into H 2 was investigated. It is found that at operation temperature of 550 °C, the current density of the SOEC prepared in this paper can reach 2.263 A cm−2 at 1.6 V. The composite electrolyte in the electrolysis cell reaches an ionic conductivity of 0.572 S cm−1 in the SOEC mode. The excellent hydrogen production performance proves that this new type of electrolysis cell with lithium compounds as electrodes is a promising and potential proton conductive low-temperature SOEC. • SOEC with NCAL electrodes was fabricated. • Proton conductivity of the composite electrolyte reaches 0.572 S cm−1 at 550 °C. • The electrolytic current density of the SOEC reaches 2.263 A·cm−2 at 1.6 V. • Provided a new type of SOEC and related electrolytic cell material. [ABSTRACT FROM AUTHOR]

One of the effective methods to improve the energy density and safety of lithium metal batteries is to use composite solid electrolytes with high voltage and good performance. However, the low ionic conductivity at room temperature and the unsatisfactory Li+ migration number of composite solid electrolytes lead to the growth of lithium dendrites and the increase of internal resistance, which restricts the industrialization of composite electrolytes for solid-state lithium batteries. This work prepares a Li6.4La3Zr1.4Ta0.6O12 (LLZTO)/polyethylene oxide (PEO)/polyvinylidene fluoride (PVDF) composite electrolyte. In this "polymer in ceramic" type electrolyte, the combination of PEO with PVDF and LLZTO reduces the crystallinity of PEO and promotes the rapid migration of Li+ along the PEO polymer molecular chain through complexation and decomplexation. At the same time, LLZTO, which has an excellent ion conduction function, introduces new ion conduction channels when combined with PEO and PVDF, thereby further improving ion conductivity. The LP82 composite electrolyte has a Li+ migration number of 0.78 and an electrochemical stability window of 5.5 V and exhibits excellent flexibility. The Li/LP82 electrolyte/Li battery has a relatively stable voltage of 0.04 V at 0.1 mA cm−2 and a stable cycling of 1000 h. The discharge specific capacity of the LiFePO4/LP82/Li battery is 144.4 mA h g−1 at 0.1 C after 180 cycles, and the capacity retention is 90.7%. This work provides a good reference for the preparation of composite electrolytes with simple processes, high voltage, and high performance. [ABSTRACT FROM AUTHOR]

This paper presents the results of research into improving the ionic conductivity of Molten Carbonate Fuel Cell by modifying the matrix material. So far, we have succeeded in using materials such as YSZ and SDC, but we are now trying to use powders based on Ba Na and TiO 2. These materials are characterized by their oxygen ion conductivity at elevated temperatures. A matrix of these materials was produced and used to build MCFCs. Based on the experiments carried out and the mathematical model of the fuel cell, the contribution of the oxygen ion conductivity to the total ionic conductivity was determined. • Research on oxygen ion conduction materials was performed. • BNT material has best oxygen ion conductivity parameters and was chosen for experiments. • New matrix made of BNT was manufactured. • Composite Li/K and BNT membrane was investigated under EIS and in fuel cell. • Model including ionic conductivity and tortuosity is presented and validated. [ABSTRACT FROM AUTHOR]

The low ionic conductivity of proton conductor electrolytes at low temperatures was one of the key issues that restrict the reduction of operating temperature in ceramic fuel cells. The traditional Y-doped BaCeO 3 proton conductor (BCY) has an ionic conductivity of only a few tens of mS·cm−1 at 500 °C, which cannot meet the needs of high-performance low-temperature ceramic fuel cells. In this paper, we found that the ionic conductivity of the composite electrolyte made by adding 20 % Li 2 O to BCY at 550 °C was 0.526 S cm−1, which was 40 times that of the dense BCY electrolyte sintered at 1550 °C. The maximum power density of a ceramic fuel cell using a BCY- Li 2 O composite material with a thickness of 1 mm as the electrolyte and porous Ag as the symmetrical electrode was 129 mW cm−2 in H 2 at 550 °C. The characterization results of XRD, EPR, and FTIR showed that there may be a region with a large number of oxygen vacancies and lithium vacancies created at the interface of the BCY and Li 2 O–LiOH composite electrolyte formed in the BCY-Li 2 O composite electrolyte during the testing conditions for fuel cell performance due to the migration of Li+. The formation of this region should be the main reason for the extremely high conductivity of the BCY-Li 2 O–LiOH composite electrolytes formed in the cell at low temperatures. [ABSTRACT FROM AUTHOR]

Abstract Inferior air stability is a primary barrier for large‐scale applications of garnet electrolytes in energy storage systems. Herein, a deeply hydrated hydrogarnet electrolyte generated by a simple ion‐exchange‐induced phase transition from conventional garnet, realizing a record‐long air stability of more than two years when exposed to ambient air is proposed. Benefited from the elimination of air‐sensitive lithium ions at 96 h/48e sites and unobstructed lithium conduction path along tetragonal sites (12a) and vacancies (12b), the hydrogarnet electrolyte exhibits intrinsic air stability and comparable ion conductivity to that of traditional garnet. Moreover, the unique properties of hydrogarnet pave the way for a brand‐new aqueous route to prepare lithium metal stable composite electrolyte on a large‐scale, with high ionic conductivity (8.04 × 10−4 S cm−1), wide electrochemical windows (4.95 V), and a high lithium transference number (0.43). When applied in solid‐state lithium batteries (SSLBs), the batteries present impressive capacity and cycle life (164 mAh g−1 with capacity retention of 89.6% after 180 cycles at 1.0C under 50 °C). This work not only designs a new sort of hydrogarnet electrolyte, which is stable to both air and lithium metal but also provides an eco‐friendly and large‐scale fabrication route for SSLBs.

A disordered sodium borohydride (NaBH4) environment to facilitate Na+ mobility was achieved by partially hydrolyzing NaBH4 and this significantly improved Na+ ionic conductivity to 10−3 S cm−1 at 75 °C. The reaction rate of NaBH4 self-hydrolysis, however, is determined by several parameters, including the reaction temperature, the molar ratio between NaBH4 and H2O, and the pH value; but these factors are hard to control. In this paper, poly(ethylene oxide) (PEO), capable of retaining H2O through hydrogen bonding, was used in an attempt to better control the amount of H2O available for NaBH4 self-hydrolysis. This strategy led to the ionic conductivity of 1.6 × 10−3 S cm−1 at 45 °C with a Na+ transference number of 0.54. The amorphous nature of the PEO matrix in hydrolyzed NaBH4 is also believed to provide a conduction path for fast Na+ conduction.

Thin and flexible composite solid-state electrolyte (SSE) is considered to be a prospective candidate for lithium-oxygen (Li-O2) batteries with the aim to address the problems of unsatisfied safety, terrible durability as well as inferior electrochemical performance. Herein, in order to improve the safety and durability, a succinonitrile (SN) modified composite SSE is proposed. In this SSE, SN is introduced for eliminating the boundary between ceramic particles, increasing the amorphous region of polymer and ensuring fast ionic transport. Subsequently, the symmetric battery based on the proposed SSE achieves a long cycle life of 3000 h. Moreover, the elaborate cathode interface through the SN participation effectively reduces the barriers to the combination between lithium ions and electrons, facilitating the corresponding electrochemical reactions. As a result, the solid-state Li-O2 battery based on this SSE and tuned cathode interface achieves improved electrochemical performance including large specific capacity over 12,000 mAh g−1, enhanced rate capacity as well as stable cycle life of 54 cycles at room temperature. This ingenious design provides a new orientation for the evolution of solid-state Li-O2 batteries.

Molten Carbonate Fuel Cells (MCFCs) are a promising technology as sustainable power generators as well as CO2 selective concentrators for carbon capture applications. Looking at the current cell configuration, several issues, which hinders a stable long-term operation of the system, are still unsettled. According to reference studies, the ceramic matrix is one of the most critical components in view of its high impact on the cell performance since it can influence both the stability and the reaction path. Indeed, it provides the structural support and holds the molten carbonates used as electrolyte, requiring a good mechanical strength despite of a porous structure, a high specific surface area and a sufficient electrolyte wettability to avoid the electrode flooding. The matrix structure, its key-features and degradation issues are discussed starting from the state-of-the-art lithium aluminate LiAlO2 usually strengthened with Al based reinforcement agents. Since the achievable performance is strictly dependent on manufacturing, a devoted section focuses on available techniques with a view also of their environmental impacts. Considering a still insufficient performance due to the material structural and chemical instability favoured by stressful working conditions, the electric conductive ceramics are presented as alternative matrixes permitting to increase the cell performance combining oxygen and carbonate ion paths.

[Display omitted] • Cationic surfactant CTAB was used to improve the dispersion of LLZTO with PEO. • CTAB modified electrolyte have better organic–inorganic interface contact. • CTAB modified electrolyte show higher interfacial stability and ionic conductivity. • CTAB modified electrolyte exhibit better rate capability and cycling stability. The garnet-type solid electrolyte Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) was modified with a cationic surfactant Cetyltrimethylammonium Bromide (CTAB) to improve the dispersion of LLZTO inorganic particles in Poly (ethylene oxide) (PEO) electrolyte (PEO-LLZTO@CTAB) by a liquid phase casting method. During fabrication, the cationic modifier CTAB is uniformly adsorbed on the surface of LLZTO particles, which can effectively reduce their surface energy and lead to a thin CTAB surface coating layer. This fabricated PEO-LLZTO@CTAB can avoid the aggregation of LLZTO particles in the composite solid-state electrolyte (CSSE) and improve the interfacial contact at the PEO/LLZTO interface, thus reducing the overall resistance of PEO-LLZTO@CTAB/Li half-cell and inhibiting the dendrite growth during cycling. The all-solid-state batteries (ASSBs) with LiFePO 4 (LFP) as the cathode, PEO-LLZTO@CTAB as the electrolyte and Li as the anode exhibit a high initial discharge capacity of 146.6 mAh-g−1, excellent rate performance and high-capacity retention of 91.0 % after 300 cycles at 0.2 C multiplier and 60 °C within the voltage range of 2.7–4.0 V. [ABSTRACT FROM AUTHOR]

Lithium metal batteries based on solid electrolytes are considered as promising candidates with high energy density and safety. However, the weak solid-solid contact between electrolyte and electrode can easily lead to interface instability and lithium ions discontinuous migration, which seriously reduces the electrochemical performance of the battery. Herein, we construct a soft gel interfacial layer to improve the stability of the solid-solid interface between electrolyte and electrode by means of polyester-based monomers and imidazole-based ionic liquids. Based on this, garnet-type Li6.4La3Zr1.4Ta0.6O12 (LLZTO) particles as inorganic ceramic filler were introduced in the layer to obtain composite electrolytes with high ionic conductivity (up to 1.1 × 10−3 S/cm at 25 °C). As a result, the assembled lithium symmetric battery of Li|THCE-15%LLZTO|Li suggests excellent cycling stability with 700 h at 0.1 mA/cm2 at 50 °C, and the lithium metal batteries of LFP|THCE-15%LLZTO|Li delivers high initial discharge capacity of 128.2 mA ·h/g with capacity retain of 75.48% after 150 cycles at 2 C. This work paves a new route to build safe and stable lithium metal batteries with synergistic introduction of composite electrolytes between electrolyte and electrode using soft gel interfacial layer and inorganic filler.

All-solid-state lithium batteries are a promising alternative to commercially available lithium-ion batteries due to their ability to achieve high energy density, safety, and compactness. Electrolytes are key components of all-solid-state batteries, as they are crucial in determining the batteries' efficiency. Herein, the structure of LiM2(PO4)3 (M = Ti, Ge, Zr) and lithium-ion migration mechanisms are introduced as well as different synthetic routes and doping (co-doping), and their influence on conductivity is discussed. The effective methods of reducing electrolyte/electrode interface resistance and improving ion-conducting properties are summarized. In addition, different polymer/NASICON composites are considered. The challenges and prospects of practical applications of NASICON-type lithium phosphates as electrolytes for all-solid-state batteries are discussed. [ABSTRACT FROM AUTHOR]

Polyethylene oxide based solid polymer electrolytes (SPEs) are safer alternatives to the current flammable liquid electrolytes used in lithium‐ion batteries. Lithium ions are typically thought to conduct through the amorphous regions of SPEs with the aid of polymer segmental motion, which is correlated with the glass transition temperature (Tg). The ionic conductivity is generally increased by making the polymer more flexible (decreasing Tg) and/or by increasing the amorphous regions of the SPE, at the cost of compromising its stiffness. This trade‐off makes it impossible to optimize both ionic conductivity and stiffness of SPEs. By incorporating a metal–organic framework (MOF) nanowhisker with the composition EO:Li = 6:1 [EO = ether oxygen, Li = lithium], we synthesized a unique composite electrolyte. We observed an atypical conductivity mechanism in this composite electrolyte, where lithium ions conduct through the crystalline regions without decreasing Tg or increasing amorphous fraction. The room‐temperature ionic conductivity of the 6:1 polymer electrolyte increased by almost 400% when 2 wt% MOF nanowhisker was added. Our results supported the potential of a composite electrolyte, which enables simultaneous improvement in both conductivity and stiffness. [ABSTRACT FROM AUTHOR]

Traditional lithium–air batteries (LABs) have been seriously affected by cycle performance and safety issues due to many problems such as the volatility and leakage of liquid organic electrolyte, the generation of interface byproducts, and short circuits caused by the penetration of anode lithium dendrite, which has hindered its commercial application and development. In recent years, the emergence of solid-state electrolytes (SSEs) for LABs well alleviated the above problems. SSEs can prevent moisture, oxygen, and other contaminants from reaching the lithium metal anode, and their inherent performance can solve the generation of lithium dendrites, making them potential candidates for the development of high energy density and safety LABs. This paper mainly reviews the research progress of SSEs for LABs, the challenges and opportunities for synthesis and characterization, and future strategies are addressed. [ABSTRACT FROM AUTHOR]

The use a stabilized lithium structure as cathode material for batteries could be a fundamental alternative in the development of next-generation energy storage devices. However, the lithium structure severely limits battery life causes safety concerns due to the growth of lithium (Li) dendrites during rapid charge/discharge cycles. Solid electrolytes, which are used in highdensity energy storage devices and avoid the instability of liquid electrolytes, can be a promising alternative for next-generation batteries. Nevertheless, poor lithium ion conductivity and structural defects at room temperature have been pointed out as limitations. In this study, through the application of a low-dimensional graphene quantum dot (GQD) layer structure, stable operation characteristics were demonstrated based on Li+ ion conductivity and excellent electrochemical performance. Moreover, the device based on the modified graphene quantum dots (GQDs) in solid state exhibited retention properties of 95.3% for 100 cycles at 0.5 C and room temperature (RT). Transmission electronmicroscopy analysis was performed to elucidate the Li+ ion action mechanism in the modified GQD/electrolyte heterostructure. The low-dimensional structure of theGQD-based solid electrolyte has provided an important strategy for stably-scalable solid-state lithium battery applications at room temperature. It was demonstrated that lithiated graphene quantum dots (Li-GQDs) inhibit the growth of Li dendrites by regulating the modified Li+ ion flux during charge/discharge cycling at current densities of 2.2-5.5 mA cm, acting as a modified Li diffusion heterointerface. A full Li GQDbased device was fabricated to demonstrate the practicality of the modified Li structure using the Li-GQD hetero-interface. This study indicates that the low-dimensional carbon structure in Li-GQDs can be an effective approach for stabilization of solid-state Li matrix architecture. [ABSTRACT FROM AUTHOR]

The dependence of the electrochemical characteristics of a layered cathode material containing LiNi _0.5 Mn _0.3 Co _0.2 O _2 on the method for applying a protective layer of nanoparticles of the lithium-conducting material Li _1.3 Al _0.3 Ti _1.7 (PO4) _3 with a NASICON structure to its surface has been studied. The surface modification has been found to improve the capacity retention in prolonged charge/discharge cycling (up to 15%) and to allow fast charge/discharge processes. The possibility of using a composite electrolyte consisting of a porous ceramic matrix of aluminum-substituted lithium titanium phosphate Li _1.3 Al _0.3 Ti _1.7 (PO4) _3 with a transition layer of liquid electrolyte LP-71 has been shown. The use of a thick composite solid electrolyte results in a slight reduction (∼5–7 mAh g ^−1 ) in initial capacity compared to laboratory cells with the widely used Celgard 2400 separator impregnated with liquid electrolyte. Laboratory cells assembled with a composite electrolyte showed higher stability during charge/discharge cycling: after 80 deep charge/discharge cycles, the capacity reduction was ∼12% for cells with a composite electrolyte, while for the reference cell it was ∼23%.

Solid polymer and perovskite-type ceramic electrolytes have both shown promise in advancing solid-state lithium metal batteries. Despite their favorable interfacial stability against lithium metal, polymer electrolytes face issues due to their low ionic conductivity and poor mechanical strength. Highly conductive and mechanically robust ceramics, on the other hand, cannot physically remain in contact with redox-active particles that expand and contract during charge-discharge cycles unless excessive pressures are used. To overcome the disadvantages of each material, polymer-ceramic composites can be formed; however, depletion interactions will always lead to aggregation of the ceramic particles if a homopolymer above its melting temperature is used. In this study, we incorporate Li0.33La0.56TiO3 (LLTO) nanoparticles into a block copolymer, polystyrene-b-poly (ethylene oxide) (SEO), to develop a polymer-composite electrolyte (SEO-LLTO). TEMs of the same nanoparticles in polyethylene oxide (PEO) show highly aggregated particles whereas a significant fraction of the nanoparticles are dispersed within the PEO-rich lamellae of the SEO-LLTO electrolyte. We use synchrotron hard x-ray microtomography to study the cell failure and interfacial stability of SEO-LLTO in cycled lithium-lithium symmetric cells. Three-dimensional tomograms reveal the formation of large globular lithium structures in the vicinity of the LLTO aggregates. Encasing the SEO-LLTO between layers of SEO to form a “sandwich” electrolyte, we prevent direct contact of LLTO with lithium metal, which allows for the passage of seven-fold higher current densities without signatures of lithium deposition around LLTO. We posit that eliminating particle clustering and direct contact of LLTO and lithium metal through dry processing techniques is crucial to enabling composite electrolytes.

Solid composite electrolytes combining an ionic molecular phase to facilitate ion transport with a polymeric component to provide mechanical strength are promising material for solid-state batteries. However, the structure-property relationships of these complex composites are not fully understood. Herein we study composites combining the non-flammability and thermal stability of the organic ionic plastic crystal (OIPC) N-methyl-N-ethylpyrrolidinium bis(trifluoromethanesulfonyl) amide [C2mpyr][TFSI] with the mechanical strength of acrylic polymer nanoparticles functionalised with sulphonamide groups having lithium counter-cations. The effect of the formation of interfaces and interfacial regions between the OIPC and polymer nanoparticle on the thermal stability, ion transport, morphology and ion dynamics were studied. It was found that the composites where an interphase was formed by local mixing of the polymer with the OIPC upon heating showed higher local disorder in the OIPC phase and enhanced ion transport in comparison with the as-prepared composites. In addition, doping the composite with LiTFSI salt led to further structural disorder in the OIPC and a selective increase in lithium-ion mobility. Such an improved fundamental understanding of structure, dynamics and interfacial regions in solid electrolyte composites can inform the design of OIPC-polymer nanoparticle composites with enhanced properties for application as solid electrolyte in batteries.

Metal–sulfur batteries, especially lithium/sodium–sulfur (Li/Na-S) batteries, have attracted widespread attention for large-scale energy application due to their superior theoretical energy density, low cost of sulfur compared to conventional lithium-ion battery (LIBs) cathodes and environmental sustainability. Despite these advantages, metal–sulfur batteries face many fundamental challenges which have put them on the back foot. The use of ether-based liquid electrolyte has brought metal–sulfur batteries to a critical stage by causing intermediate polysulfide dissolution which results in poor cycling life and safety concerns. Replacement of the ether-based liquid electrolyte by a solid electrolyte (SEs) has overcome these challenges to a large extent. This review describes the recent development and progress of solid electrolytes for all-solid-state Li/Na-S batteries. This article begins with a basic introduction to metal–sulfur batteries and explains their challenges. We will discuss the drawbacks of the using liquid organic electrolytes and the advantages of replacing liquid electrolytes with solid electrolytes. This article will also explain the fundamental requirements of solid electrolytes in meeting the practical applications of all solid-state metal–sulfur batteries, as well as the electrode–electrolyte interfaces of all solid-state Li/Na-S batteries. [ABSTRACT FROM AUTHOR]

Lithium metal batteries hold promise for energy storage applications but suffer from uncontrolled lithium dendrites. In this study, a new composite membrane based on modified natural polymer and ZIF‐67 is designed and prepared by the in situ composite method for the first time. Among them, a modified natural polymer composed of lithium alginate (LA) and polyacrylamide (PAM) can be obtained by electrospinning. Importantly, the polar functional groups of natural polymers can interact by hydrogen bonding and MOFs can construct lithium‐ion transport channels. Consequently, compared with LA‐PAM electrolyte without MOF, the electrochemical stability window of ZIF‐67‐LA‐PAM electrolyte becomes wider from 4.5 to 5.2 V, and the lithium‐ion transference number (tLi+) enhances from 0.326 to 0.627 at 30°C. It is worth noting that the symmetric cells with ZIF‐67‐LA‐PAM have superior stable cycling performance at 40 and 100 mA cm−2, and a high rate at 10C and 20C for LFP cells. Besides, the cell with NCM811 high‐voltage cathode can run stably for 400 cycles with an initial discharge capacity of 136.1 mAh g−1 at 0.5C. This work provides an effective method for designing and preparing MOF‐natural polymer composite electrolytes and exhibits an excellent application prospect in high‐energy‐density lithium metal batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • LL-GCE has high ionic conductivity and Li+ transference number. • LL-GCE possesses favorable anion-rich solvation structures. • LL-GCE generates LiF-rich CEI and SEI layers after cycling. • LL-GCE shows outstanding compatibility with both Li anode and high-voltage cathode. Ether-based polymer electrolyte shows promising potential for application in solid-state lithium batteries owing to its cost-effectiveness, excellent flexibility, and above all, remarkable stability to lithium metal anode. However, it still suffers from challenges related to low ionic conductivity and inferior oxidation resistance. Herein, an ether-based gel composite electrolyte containing Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (LLZTO) ceramics (LL-GCE) is fabricated via an in-situ polymerization method which can guarantee good interface contact with electrodes. The ceramics not only activate the interaction between polymers and lithium salts, resulting in significantly enhanced ionic conductivity (7.9 × 10−4 S cm−1), but also collaborate with poly(1,3-dioxolane) (PDOL) to construct favorable anion-rich solvation configurations, which effectively restrict the anion migration with Li+ transference number significantly increased to 0.83. Furthermore, the regulated solvation structures can passivate the electrode surface with a high content of robust LiF components formed on the electrolyte/electrode interphase. Consequently, the composite electrolyte demonstrates excellent abilities to inhibit Li dendrite growth and match with high-voltage cathodes. For instance, the LiFePO 4 ||Li cell using such electrolyte conveys a capacity of 135.4 mAh/g and the capacity retention is 99.3 % after 250 cycles at 1C. The LiCoO 2 ||Li full cell also shows excellent cycling performance. This work provides an effective strategy to modify ether-based polymer electrolytes and can boost their development in high-performance solid state lithium metal batteries. [ABSTRACT FROM AUTHOR]

• A composite electrolyte is fabricated using a polymer matrix and glass fiber fabric reinforcement. • The composite electrolyte simultaneously exhibits mechanical robustness and high ionic conductivity. • The structural Zn-ion batteries based on composite electrolytes simultaneously achieve energy storage and mechanical loading. Mechanically robust electrolytes with high ionic conductivity play an essential role in carbon fiber (CF) structural batteries that simultaneously store energy and bear mechanical loads. However, multifunctional composite electrolytes are rarely developed, especially for air-stable and safe structural Zn-ion batteries. Herein, a composite electrolyte GF-SPE is designed and fabricated by integrating ionic conductive poly(ethylene glycol) diacrylate (PEGDA)-based solid-state polymer electrolyte (SPE) matrix and glass fiber fabric (GF) reinforcement, which simultaneously exhibits mechanical robustness and high ionic conductivity, facilitating homogeneous Zn electrodeposition without obvious side reaction, such as dendrite growth, corrosion et al. Therefore, the symmetric cells Zn//GF-SPE//Zn cell can cycle stably for more than 800 h at 1 mA cm−2. The carbon fiber structural battery fabricated with composite structural electrolyte GF-SPE delivers a high energy density of 19.35 Wh kg−1 based on the total mass of the whole device and cycling stability over 1,000 cycles in extreme environments. Furthermore, the high capacity of structural Zn-ions batteries can be maintained when they withstand flexural stress of over 120 MPa. The in-situ mechanical-electrochemical testing further confirms the priority of structural Zn-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract Lithium metal batteries hold promise for energy storage applications but suffer from uncontrolled lithium dendrites. In this study, a new composite membrane based on modified natural polymer and ZIF‐67 is designed and prepared by the in situ composite method for the first time. Among them, a modified natural polymer composed of lithium alginate (LA) and polyacrylamide (PAM) can be obtained by electrospinning. Importantly, the polar functional groups of natural polymers can interact by hydrogen bonding and MOFs can construct lithium‐ion transport channels. Consequently, compared with LA‐PAM electrolyte without MOF, the electrochemical stability window of ZIF‐67‐LA‐PAM electrolyte becomes wider from 4.5 to 5.2 V, and the lithium‐ion transference number (tLi+) enhances from 0.326 to 0.627 at 30°C. It is worth noting that the symmetric cells with ZIF‐67‐LA‐PAM have superior stable cycling performance at 40 and 100 mA cm−2, and a high rate at 10C and 20C for LFP cells. Besides, the cell with NCM811 high‐voltage cathode can run stably for 400 cycles with an initial discharge capacity of 136.1 mAh g−1 at 0.5C. This work provides an effective method for designing and preparing MOF‐natural polymer composite electrolytes and exhibits an excellent application prospect in high‐energy‐density lithium metal batteries.

[Display omitted] • A solvent-free process was raised to prepare composite solid electrolyte. • A large-scale size of ca. 40 m was demonstrated. • Tensile strength was increased to three times due to the solvent-free feature. • Stable operation without lithium dendrite for over 3700 h was demonstrated. Composite solid-state electrolytes (CSEs) are regarded as a promising alternative for the next‐generation lithium-ion batteries because they integrate the advantages of inorganic electrolytes and organic electrolytes. However, there are two issues faced by current CSEs: 1) a green and feasible approach to prepare CSEs in large scales is desired; and 2) the trace solvents, remaining from the preparation processes, lead to some serious concerns, such as safety hazard issues, electrolyte–electrode interfacial issues, and reduced durability of batteries. Here, a continuous thermal-extrusion process is presented to realize the large-scale fabrication of solvent‐free CSE. A 38.7-meter CSE membrane was prepared as a demonstration in this study. Thanks to the elimination of residual solvents, the electrolyte membrane exhibited a high tensile strength of 3.85 MPa, satisfactory lithium transference number (0.495), and excellent electrochemical stability (5.15 V). Excellent long-term stability was demonstrated by operating the symmetric lithium cell at a stable current density of 0.1 mA cm−2 for over 3700 h. Solvent-free CSE lithium metal batteries showed a discharge capacity of 155.7 – 25.17 mAh g−1 at 0.1 – 2.0C, and the discharge capacity remained 78.1% after testing for 380cycles. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries (LSBs) represent a promising next-generation energy storage system, with advantages such as high specific capacity (1675 mAh g−1), abundant resources, low price, and ecological friendliness. During the application of liquid electrolytes, the flammability of organic electrolytes, and the dissolution/shuttle of polysulfide seriously damage the safety and the cycle life of lithium–sulfur batteries. Replacing a liquid electrolyte with a solid one is a good solution, while the higher mechanical strength of solid-state electrolytes (SSEs) has an inhibitory effect on the growth of lithium dendrites. However, the lower ionic conductivity, poor interfacial contact, and relatively narrow electrochemical window of solid-state electrolytes limit the commercialization of solid-state lithium–sulfur batteries (SSLSBs). This review describes the research progress in LSBs and the challenges faced by SSEs, which are classified as polymer electrolytes, inorganic solid electrolytes, and composite electrolytes. The advantages, as well as the disadvantages of various types of electrolytes, the common coping strategies to improve performance, and future development trends, are systematically described. [ABSTRACT FROM AUTHOR]

The integration of the flexibility of organic polymer electrolyte and high ionic conductivity of the ceramic electrolyte is attempted in search of efficient and safer battery. Composite solid polymer electrolyte (CSPE) provides high ionic conductivity with a sustainable thin film of electrolyte having the synergistic effect of ionic liquid and active inorganic filler. The CSPE is synthesized by the solution cast technique using Na 3 Zr 2 Si 2 PO 12 (NZSP) as ceramic and poly(vinylidene fluoride-hexafluoropropylene) with Salt-Ionic liquid as polymer electrolyte. X-ray diffraction (XRD) of CSPE includes amorphous nature due to the polymer part as well as crystalline peaks of ceramic NZSP, simultaneously. The prepared CSPE sample shows homogeneous and interconnected surface morphology is observed by Scanning electron microscopy (SEM) image. Thermogravimetric analysis (TGA) shows electrolyte is thermally stable up to 200 °C and differential scanning calorimetry (DSC) reveals decrease in degree of crystallinity due to NZSP addition in the CSPE. By complex impedance spectroscopy (CIS), room temperature ionic conductivity of the prepared CSPE is found ~1.03 mS/cm. The dielectric behaviour of the prepared electrolyte is also studied to investigate the ion dynamics within the sample. The cationic transference number is 0.53 and the electrochemical stability window (ESW) of the CSPE is 4.9 V which is suitable for sodium solid-state batteries applications., (© 2024 Wiley-VCH GmbH.)

All-solid-state lithium batteries are a promising alternative to commercially available lithium-ion batteries due to their ability to achieve high energy density, safety, and compactness. Electrolytes are key components of all-solid-state batteries, as they are crucial in determining the batteries’ efficiency. Herein, the structure of LiM2(PO4)3 (M = Ti, Ge, Zr) and lithium-ion migration mechanisms are introduced as well as different synthetic routes and doping (co-doping), and their influence on conductivity is discussed. The effective methods of reducing electrolyte/electrode interface resistance and improving ion-conducting properties are summarized. In addition, different polymer/NASICON composites are considered. The challenges and prospects of practical applications of NASICON-type lithium phosphates as electrolytes for all-solid-state batteries are discussed.

Samarium, gadolinium, and yttrium co-doped ceria (Ce0.8Sm0.16Y0.03Gd0.01O1.9, CSYG) and BaIn0.3Ti0.7O2.85 (BIT07) powders were prepared by sol-gel and solid-state reaction methods, respectively. CSYG-BIT07 composite materials were obtained by mechanically mixing the two powders in different ratios and calcining at 1300 °C for 5 h. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), as well as electrical properties and thermal expansion coefficient (TEC) measurements. A series of CSYG-BIT07 composite materials with relative densities higher than 95% were fabricated by sintering at 1300 °C for 5 h. The performance of the CSYG-BIT07 composite electrolyte was found to be related to the content of BIT07. The CSYG-15% BIT07 composite exhibited high oxide ion conductivity (σ800°C = 0.0126 S·cm−1 at 800 °C), moderate thermal expansion (TEC = 9.13 × 10−6/K between room temperature and 800 °C), and low electrical activation energy (Ea = 0.89 eV). These preliminary results indicate that the CSYG-BIT07 material is a promising electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). [ABSTRACT FROM AUTHOR]

The flexible and less flammable solid polymer electrolytes are attractive candidates for high specific energy density lithium batteries. However, the use of polymer electrolytes in rechargeable batteries for EVs is hindered because of their low lithium‐ion conductivity at room temperature and lithium dendrite formation during lithium deposition at high current density. To improve the room temperature conductivity of polymer electrolytes, composite lithium‐ion conductors consisting of polymer and ionic liquids or inorganic solid lithium ion conductors have been examined over the past two decades. The polymer electrolyte with ionic liquid showed ionic conductivity of more than 10−4 S cm−1 at room temperature, but lithium dendrite‐free composite electrolytes have not yet been reported at room temperature and a high current density. The flexible composite electrolytes of polymers and lithium‐ion conductive solid electrolytes showed high ionic conductivity of more than 2×10−4 S cm−1 and no dendrite short‐circuit was observed at room temperature and 1.0 mA cm−1 for long cycling. The suppression of lithium dendrite formation in the composite electrolyte is due to the formation of a stable interface layer between the lithium electrode and composite electrolyte. At present, no room temperature all‐solid‐state batteries have been developed with performance comparable to conventional lithium‐ion batteries with liquid electrolytes. One of the disadvantage of the lithium batteries with the composite polymer electrolyte is higher mass of the electrolyte than that of a liquid electrolyte with a porous separator. The specific energy density of the batteries depends on the thickness of the electrolyte and the specific area capacity. At present, the thickness of the polymer composite electrolytes is in a range of 50–200 μm. The specific energy density of the lithium battery with a 100 μm thick composite electrolyte is 430 Wh kg−1 at 10 mAh cm−2, which is 1.4 times higher than that of the conventional Li‐ion battery. A high specific area capacity battery with a thin polymer composite electrolyte should be developed to obtain a high energy density battery. We are anxiously expecting a mechanically stable composite polymer electrolyte thin film of less than 100 μm thick with high Li‐ion conductivity more than 10−3 S cm−1 at room temperature and low interface resistance with Li electrode. The addition of small amount of a low molecular weight additive into the composite electrolytes is effective to improve the interface resistance between the lithium electrode and composite electrolyte, which results in no dendrite formation at high current density and room temperature. [ABSTRACT FROM AUTHOR]

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