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Highlights This study introduces an innovative 3D-printed electrolyte with vertically aligned ion transport network, which contains well-dispersed nanoscale Ta-doped Li7La3Zr2O12 in a poly(ethylene glycol) diacrylate matrix. The 3DSE architecture enables efficient ion transport across the Li/electrolyte and electrolyte/cathode interfaces, which allows for increased active material mass loading and enhanced interfacial adhesion. The p-3DSE Li symmetric cell displays an impressive critical current density value of 1.92 mA cm−2 and stable operation for 2600 h at room temperature. Full cells using p-3DSE achieve notable areal capacities.

Highlights A scalable tape-casting method produces self-supported porous Li6.4La3Zr1.4Ta0.6O12. Combining the in-situ polymerization approach, a composite solid electrolyte with superior electrochemical properties is fabricated. Solid-state Li|CSE|LiNi0.8Co0.1Mn0.1O2 cells show remarkable cyclability and rate capability. LiF-and B-rich interphase layers mitigate interfacial reactions, enhancing solid-state battery performance.

Solid-state batteries (SSBs) have been widely studied as next-generation lithium-ion batteries (LiBs) for many electronic devices due to their high energy density, stability, nonflammability, and chemical stability compared to LiBs which consist of liquid electrolytes. However, solid electrolytes exhibit poor electrochemical characteristics due to their interfacial properties, and the sintering process, which necessitates high temperatures, is an obstacle to the commercialization of SSBs. Hence, the aim of this study was to improve the interfacial properties of the lithium tantalum phosphate (LTPO) solid electrolyte by adding succinonitrile (SN) on the interface of the LTPO particle to enhance ionic conductivity without the sintering process. Electrochemical impedance spectroscopy (EIS), the Li symmetric cell test, and the galvanostatic cycle test were performed to verify the performance of the SN-containing LTPO composite electrolyte. The LTPO composite solid electrolyte exhibited a high ionic conductivity of 1.93 × 10−4 S/cm at room temperature (RT) compared to the conventional LTPO. Also, it showed good cycle stability, and low interfacial resistance with Li metal, ensuring electrochemical stability. On the basis of our experimental results, the performance of solid electrolytes could be improved by adding SN and lithium salt. In addition, the SN can be used to fabricate the solid electrolytes without the sintering process at high temperatures.

The solid oxide electrolyte Li1.5Al0.5Ge1.5(PO4)3 (LAGP) with a NASICON structure has a high bulk ionic conductivity of 10−4 S cm−1 at room temperature and good stability in the air because of the strong P5+-O2− covalence bonding. However, the Ge4+ ions in LAGP are quickly reduced to Ge3+ on contact with the metallic lithium anode, and the LAGP ceramic has insufficient physical contact with the electrodes in all-solid-state batteries, which limits the large-scale application of the LAGP electrolyte in all-solid-state Li-metal batteries. Here, we prepared flexible PEO/LiTFSI/LAGP composite electrolytes, and the introduction of LAGP as a ceramic filler in polymer electrolytes increases the total ionic conductivity and the electrochemical stability of the composite electrolyte. Moreover, the flexible polymer shows good contact with the electrodes, resulting in a small interfacial resistance and stable cycling of all-solid-state Li-metal batteries. The influence of the external pressure and temperature on Li+ transfer across the Li/electrolyte interface is also investigated.

Abstract All‐solid‐state Li metal batteries (ASSLMBs) have been considered the most promising candidates for next‐generation energy storage devices owing to their high‐energy density and safety. However, some obstacles such as thick solid electrolyte (SSEs) and unstable interface between the solid‐state electrolytes (SSEs) and the electrodes have restricted the practical application of ASSLBs. Here, the scalable polyimide (PI) film reinforced asymmetric ultra‐thin (~20 μm) composite solid electrolyte (AU‐CSE) with a ceramic‐rich layer and polymer‐rich layer is fabricated by a both‐side casting method and rolling process. The ceramic‐rich layer not only acts as a “securer” to inhibit the lithium dendrite growth but also redistributes Li‐ions uniform deposition, while the polymer‐rich layer improves the compatibility with cathode materials. As a result, the obtained AU‐CSE demonstrates an ionic conductivity of 1.44 × 10−4 S cm−1 at 35°C. The PI‐reinforced AU‐CSE enables Li/Li symmetric cell stable cycling over 1200 h at 0.2 mA cm−2 and 0.2 mAh cm−2. Li/LiNi0.6Co0.2Mn0.2O2 and Li/LiFePO4 ASSLMBs achieve superior performances at 35°C. This study provides a new way of solving the interface problems between SSEs and electrodes and developing high‐energy‐density ASSLMBs for practical applications.

For solid-state electrolyte in lithium-ion batteries, high crystal boundary impedance leads to tough electrolyte-electrode interfacial issues. Here, we introduce garnet Li6.4La3Zr1.4Ta0.6O12 (LLZTO) nanoparticles and succinonitrile (SN) into thermal polyurethane (TPU) to fabricate a composite solid-state electrolyte (TPU/LLZTO/SN), achieving high ionic conductivity of 6.452 × 10−4 S cm−1. The TPU polymer with specific soft and hard segments allows lithium ions fast transport and holds good mechanical strength as the electrolyte matrix. The ionic conductor LLZTO further improves the ionic conductivity and mechanical property of the composite electrolyte membrane. Additional SN supplies the electrolyte’ wide electrochemical stabilization window, and enhances the metallic lithium compatibility of the TPU matrix. As a result, the as prepared TPU/LLZTO/SN electrolyte presents high lithium ions transference number of 0.64, and also good mechanical property.

Composite solid electrolytes (CSEs), often incorporating succinonitrile (SCN), offer promi I confirm sing solutions for improving the performance of all-solid-state batteries. These electrolytes are typically made of ceramics such as Li7La3Zr2O12 (LLZO) and polymers such as poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). Garnet-applied polymer–ceramic electrolyte (g-PCE) is composed of PVDF-HFP, SCN, and LLZO. However, the interface between SCN and LLZO is reportedly unstable owing to the polymerization of SCN. This polymerization could cause two serious problems: (1) gelation during the mixing of LLZO and SCN and (2) degradation of ionic performance during charge and discharge. To prevent this catalytic reaction, polyacrylonitrile (PAN) can be added to the g-PCE (g-PPCE). PAN blocks the polymerization of SCN through a cyclization process involving La ions which occurs more rapidly than SCN polymerization. In this study, the enhanced chemical stability of the garnet-applied PAN-added polymer ceramic electrolyte (g-PPCE) was achieved by using an impregnation process which added SCN with 5 wt.% of PAN. The resulting CSE has an ionic conductivity of ~10-⁴ S/cm at room temperature. Coin-type cells assembled with LFP (LiFePO4) and LNCM (LiNi0.6Co0.2Mn0.2O2) cathodes with Li-metal anodes show specific discharge capacities of 150 and 167 mAh/g at 0.1 C, respectively, and stable cycle performance. Additionally, a pouch-type cell with a discharge capacity of 5 mAh also exhibits potential electrochemical performance.

Solid sodium ion batteries (SIBs) show a significant amount of potential for development as energy storage systems; therefore, there is an urgent need to explore an efficient solid electrolyte for SIBs. Na3Zr2Si2PO12 (NZSP) is regarded as one of the most potential solid-state electrolytes (SSE) for SIBs, with good thermal stability and mechanical properties. However, NZSP has low room temperature ionic conductivity and large interfacial impedance. F−doped NZSP has a larger grain size and density, which is beneficial for acquiring higher ionic conductivity, and the composite system prepared with epoxy can further improve density and inhibit Na dendrite growth. The composite system exhibits an outstanding Na+ conductivity of 0.67 mS cm−1 at room temperature and an ionic mobility number of 0.79. It also has a wider electrochemical stability window and cycling stability.

The safety concerns associated with power batteries have prompted significant interest in all−solid−state lithium batteries (ASSBs). However, the advancement of ASSBs has been significantly impeded due to their unsatisfactory electrochemical performance, which is attributed to the challenging interface between the solid−state electrolyte and the electrodes. In this work, an in situ polymerized composite solid−state electrolyte (LLZTO−PVC) consisting of poly(vinylene carbonate) (PVC) and Li6.4La3Zr1.4Ta0.6O12 (LLZTO) was successfully prepared by a γ−ray irradiation technique. The novel technique successfully solved the problem of rigidity at the interface between the electrode and electrolyte. The LLZTO−PVC electrolyte exhibited a notable ionic conductivity of 1.2 × 10−4 S cm−1 25 °C, along with good mechanical strength and flexibility and an electrochemical window exceeding 4.65 V. It was showed that the LiCoO2(LCO)/LLZTO−PVC/Li battery, which achieved in situ solidification via γ−ray irradiation, can steadily work at a current density of 0.2 C at 25 °C and maintain a retention rate of 92.4% over 100 cycles. The good interfacial compatibility between electrodes and LLZTO−PVC electrolyte designed via in situ γ−ray irradiation polymerization could be attributed to its excellent electrochemical performance. Therefore, the method of in situ γ−ray irradiation polymerization provides a vital reference for solving the interface problem.

Abstract Composite solid electrolyte is a promising solution for the development of new generation of safe and high‐performance all‐solid‐state lithium batteries (ASSLBs). It combines both the advantages of inorganic electrolyte and organic polymer electrolyte, having high ionic conductivity, mechanical strength, good contact with the electrodes and high processability. In the recent decades, rare earth oxides have attracted wide attentions from researchers because of their high ionic conductivity. China is abundant in rare earth resources, so has a good chance to provide the world with high quality rare earth containing functional materials. This review paper focuses on the recent progress in the studies of composite solid electrolyte of polymer and rare earth containing lithium lanthanum zirconium and lithium lanthanum titanium oxides, and gains insights into the challenges in the field, and hopefully helps in the rational design of high performance electrolyte for the development of ASSLBs.

In order to enhance the electrochemical performance and mechanical properties of poly(ethylene oxide) (PEO)-based solid polymer electrolytes, composite solid electrolytes (CSE) composed of single-ion conducting polymer-modified SiO2, PEO and lithium salt were prepared and used in lithium-ion batteries in this work. The pyridyl disulfide terminated polymer (py-ss-PLiSSPSI) is synthesized through RAFT polymerization, then grafted onto SiO2 via thiol-disulfide exchange reaction between SiO2-SH and py-ss-PLiSSPSI. The chemical structure, surface morphology and elemental distribution of the as-prepared polymer and the PLiSSPSI-g-SiO2 nanoparticles have been investigated. Moreover, CSEs containing 2, 6, and 10 wt% PLiSSPSI-g-SiO2 nanoparticles (PLi-g-SiCSEs) are fabricated and characterized. The compatibility of the PLiSSPSI-g-SiO2 nanoparticles and the PEO can be effectively improved owing to the excellent dispersibility of the functionalized nanoparticles in the polymer matrix, which promotes the comprehensive performances of PLi-g-SiCSEs. The PLi-g-SiCSE-6 exhibits the highest ionic conductivity (0.22 mS·cm−1) at 60 °C, a large tLi+ of 0.77, a wider electrochemical window of 5.6 V and a rather good lithium plating/stripping performance at 60 °C, as well as superior mechanical properties. Hence, the CSEs containing single-ion conducting polymer modified nanoparticles are promising candidates for all-solid-state lithium-ion batteries.

As a high-efficiency energy storage and conversion device, lithium-ion batteries have high energy density, and have received widespread attention due to their good cycle performance and high reliability. However, currently commercial lithium batteries usually use organic solutions containing various lithium salts as liquid electrolytes. In practical applications, liquid electrolytes have many shortcomings and shortcomings, such as poor chemical stability, flammability, and explosion. Therefore, the liquid electrolyte has a great safety hazard. The use of solid electrolyte ensures the safety of lithium-ion batteries, and has the advantages of high energy density, good cycle performance, long life, and wide electrochemical window, making the battery safer and more durable, with higher energy density and simple battery Structural design. Solid electrolytes mainly include inorganic solid electrolytes and organic polymer solid electrolytes. Although both inorganic solid electrolytes and polymer solid electrolytes have their own advantages, as far as the existing research work is concerned, whether it is an inorganic system or a polymer system, a single-system solid electrolyte can never achieve the full performance of an ideal solid electrolyte. The composite solid electrolyte composed of active or passive inorganic filler and polymer matrix is considered as a promising candidate electrolyte for all-solid-state lithium batteries. Among many polymer systems, PEO-based is considered to be the most ideal polymer substrate. In this review article, we first introduced the structure, properties, and preparation methods of PEO-based polymer electrolytes. Furthermore, the researches related to the modification of PEO-based polymer solid electrolytes in recent years are summarized. The contribution of polymer structural modification and the introduction of additives to the ionic conductivity, electrochemical stability and mechanical properties of PEO-based solid electrolytes is described. Examples of different composite solid electrolyte design concepts were extensively discussed, such as inorganic inert nanoparticles/PEO, oxide/PEO, and sulfide/PEO. Finally, the future development direction of composite solid electrolytes was prospected.

Due to the intrinsically high ionic conductivity and good interfacial stability towards lithium, garnet-type solid electrolytes are usually introduced into polymer electrolytes as fillers to prepare polymer/garnet composite electrolytes, which can improve the ionic conductivity and enhance the mechanical strength to suppress Li dendrites. However, the surface Li2CO3 and/or LiOH passive layers which form when garnet is exposed to the air greatly reduce the enhancement effect of garnet on the composite electrolyte. Furthermore, compared with micro-size particles, nano-size garnet fillers exhibit a better effect on enhancing the performance of composite solid electrolytes. Nevertheless, inferior organic/inorganic interphase compatibility and high specific surface energy of nanofillers inevitably cause agglomeration, which severely hinders the effect of nanoparticles for promoting composite solid electrolytes. Herein, a cost-effective amphipathic 3-Aminopropyltriethoxysilane coupling agent is introduced to modify garnet fillers, which effectively expands the air stability of garnet and greatly improves the dispersion of garnet fillers in the polymer matrix. The well-dispersed garnet filler/polymer interface is intimate through the bridging effect of the silane coupling agent, resulting in boosted ionic conductivity (0.72 × 10−4 S/cm at room temperature) of the composite electrolyte, enhanced stability against lithium dendrites (critical current density > 0.5 mA/cm2), and prolonged cycling life of LFP/Li full cells.

With high safety and good flexibility, polymer-based composite solid electrolytes are considered to be promising electrolytes and are widely investigated in solid lithium batteries. However, the low conductivity and high interfacial impedance of polymer-based solid electrolytes hinder their industrial applications. Herein, a composite solid-state electrolyte containing graphene (PVDF-LATP-LiClO4-Graphene) with structurally stable and good electrochemical performance is explored and enables excellent electrochemical properties for lithium-ion batteries. The ionic conductivity of the composite electrolyte membrane containing 5 wt% graphene reaches 2.00 × 10−3 S cm−1 at 25 °C, which is higher than that of the composite electrolyte membrane without graphene (2.67 × 10−4 S cm−1). The electrochemical window of the composite electrolyte membrane containing 5 wt% graphene reaches 4.6 V, and its Li+ transference numbers reach 0.84. Assembling this electrolyte into the battery, the LFP/PVDF-LATP-LiClO4-Graphene /Li battery has a specific discharge capacity of 107 mAh g−1 at 0.2 C, and the capacity retention rate was 91.58% after 100 cycles, higher than that of the LiFePO4/PVDF-LATP-LiClO4/Li (LFP/PLL/Li) battery, being 94 mAh g−1 and 89.36%, respectively. This work provides a feasible solution for the potential application of composite solid electrolytes.

Solid-state lithium batteries have attracted much attention due to their special properties of high safety and high energy density. Among them, the polymer electrolyte membrane with high ionic conductivity and a wide electrochemical window is a key part to achieve stable cycling of solid-state batteries. However, the low ionic conductivity and the high interfacial resistance limit its practical application. This work deals with the preparation of a composite solid electrolyte with high mechanical flexibility and non-flammability. Firstly, the crystallinity of the polymer is reduced, and the fluidity of Li+ between the polymer segments is improved by tertiary polymer polymerization. Then, lithium salt is added to form a solpolymer solution to provide Li+ and anion and then an inorganic solid electrolyte is added. As a result, the composite solid electrolyte has a Li+ conductivity (3.18 × 10−4 mS cm−1). The (LiNi0.5Mn1.5O4)LNMO/SPLL (PES-PVC-PVDF-LiBF4-LAZTP)/Li battery has a capacity retention rate of 98.4% after 100 cycles, which is much higher than that without inorganic oxides. This research provides an important reference for developing all-solid-state batteries in the greenhouse.

An Li1.3Al0.3SnxTi1.7−x(PO4)3 (LATP-xSn) ceramic solid electrolyte was prepared by Sn doping via a solid phase method. The results showed that adding an Sn dopant with a larger ionic radius in a concentration of x = 0.35 enabled one to equivalently substitute Ti sites in the LATP crystal structure to the maximum extent. The uniform Sn doping could produce a stable LATP structure with small grain size and improved relative density. The lattice distortion induced by Sn doping also modified the transport channels of Li ions, which promoted the increase of ionic conductivity from 5.05 × 10−5 to 4.71 × 10−4 S/cm at room temperature. The SPE/LATP-0.35Sn/SPE composite solid electrolyte with a sandwich structure was prepared by coating, which had a high ionic conductivity of 5.9 × 10−5 S/cm at room temperature, a wide electrochemical window of 4.66 V vs. Li/Li+, and a good lithium-ion migration number of 0.38. The Li||Li symmetric battery test results revealed that the composite solid electrolyte could stably perform for 500 h at 60 °C under the current density of 0.2 mA/cm2, indicating its good interface stability with metallic lithium. Moreover, the analysis of the all-solid-state LiFePO4||SPE/LATP-0.35Sn/SPE||Li battery showed that the composite solid electrolyte had good cycling stability and rate performance. Under the conditions of 60 °C and 0.2 C, stable accumulation up to 200 cycles was achieved at a capacity retention ratio of 90.5% and a coulombic efficiency of about 100% after cycling test.

The challenge of safety problems in lithium batteries caused by conventional electrolytes at high temperatures is addressed in this study. A novel solid electrolyte (HKUST-1@IL-Li) was fabricated by immobilizing ionic liquid ([EMIM][TFSI]) in the nanopores of a HKUST-1 metal–organic framework. 3D angstrom-level ionic channels of the metal–organic framework (MOF) host were used to restrict electrolyte anions and acted as “highways” for fast Li+ transport. In addition, lower interfacial resistance between HKUST-1@IL-Li and electrodes was achieved by a wetted contact through open tunnels at the atomic scale. Excellent high thermal stability up to 300 °C and electrochemical properties are observed, including ionic conductivities and Li+ transference numbers of 0.68 × 10−4 S·cm−1 and 0.46, respectively, at 25 °C, and 6.85 × 10−4 S·cm−1 and 0.68, respectively, at 100 °C. A stable Li metal plating/stripping process was observed at 100 °C, suggesting an effectively suppressed growth of Li dendrites. The as-fabricated LiFePO4/HKUST-1@IL-Li/Li solid-state battery exhibits remarkable performance at high temperature with an initial discharge capacity of 144 mAh·g−1 at 0.5 C and a high capacity retention of 92% after 100 cycles. Thus, the solid electrolyte in this study demonstrates promising applicability in lithium metal batteries with high performance under extreme thermal environmental conditions.

A series of composite materials of general molecular formula (1 − x) Na2SO4 − (x) LDT was prepared by solid state reaction method. The phase structure and functionalization of these materials were defined by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) respectively. Differential thermal analysis (DTA) revealed that the hump of phase transition at 250 °C has decreased while its thermal stability was enhanced. Scanning electron microscopy signifies the presence of improved rigid surfaces and interphases that are accountable for the high ionic conduction due to dispersion of LDT particles in the composite systems. Arrhenius plots of the conductance show the maximum conductivity, σ = 4.56 × 10−4 S cm−1 at 500 °C for the x = 0.4 composition with the lowest activation energy 0.34 eV in the temperature range of 573–773 K. The value of dielectric constant was decreased with increasing frequency and follows the usual trend.

CsH2PO4 is a proton conductor pertaining to the acid salts group and shows a phase transition from monoclinic to cubic phase at 232 ± 2 °C under high-steam atmospheres (>30%). This cubic phase gives rise to the so-called superprotonic conductivity. In this work, the influence of the partial substitution of Cs by Ba and Rb, as well as the partial substitution of P by W, Mo, and S in CsH2PO4 on the phase transition temperature and electrochemical properties is studied. Among the tested materials, the partial substitution by Rb led to the highest conductivity at high temperature. Furthermore, Ba and S-substituted salts exhibited the highest conductivity at low temperatures. CsH2PO4 was used as electrolyte in a fully-assembled fuel cell demonstrating the applicability of the material at high pressures and the possibility to use other materials (Cu and ZnO) instead of Pt as electrode electrocatalyst. Finally, an electrolyzer cell composed of CsH2PO4 as electrolyte, Cu and ZnO as cathode and Pt and Ag as anode was evaluated, obtaining a stable production of H2 at 250 °C.