Sandwich-Structured Quasi-Solid Polymer Electrolyte Enables High-Capacity,Long-Cycling,and Dendrite-Free Lithium Metal Battery at Room Temperature

The insufficient ionic conductivity, limited lithium-ion transference number (t_Li+), and high interfacial impedance severely hinder the practical application of quasi-solid polymer electrolytes (QSPEs). Here, a sandwich-structured polyacrylonitrile (PAN) based QSPE is constructedin which MXene-SiO₂ nanosheets act as a functional filler to facilitate the rapid transfer of lithium-ion in the QSPE, and a polymer and plastic crystalline electrolyte (PPCE) interface modification layer is coated on the surface of the PAN-based QSPE of 3 wt.% MXene-SiO₂ (SS-PPCE/PAN-3%) to reduce interfacial impedance. Consequently, the synthesized SS-PPCE/PAN-3% QSPE delivers a promising ionic conductivity of ≈1.7 mS cm⁻¹ at 30 °C, a satisfactory t_Li+ of 0.51, and a low interfacial impedance. As expected, the assembled Li symmetric battery with SS-PPCE/PAN-3% QSPE can stably cycle more than 1550 h at 0.2 mA cm⁻². The Li||LiFePO₄ quasi-solid-state lithium metal battery (QSSLMB) of this QSPE exhibits a high capacity retention of 81.5% after 300 cycles at 1.0 C and at RT. Even under the high-loading cathode (LiFePO₄ ≈ 10.0 mg cm⁻²) and RT, the QSSLMB achieves a superior area capacity and good cycling performance. Besides, the assembled high voltage Li||NMC811(loading ≈ 7.1 mg cm⁻²) QSSLMB has potential applications in high-energy fields.     

Improving Room-Temperature Li-Metal Battery Performance by In Situ Creation of Fast Li+ Transport Pathways in a Polymer-Ceramic Electrolyte

Composite polymer-ceramic electrolytes have shown considerable potential for high-energy-density Li-metal batteries as they combine the benefits of both polymers and ceramics. However, low ionic conductivity and poor contact with electrodes limit their practical usage. In this study, a highly conductive and stable composite electrolyte with a high ceramic loading is developed for high-energy-density Li-metal batteries. The electrolyte, produced through in situ polymerization and composed of a polymer called poly-1,3-dioxolane in a poly(vinylidene fluoride)/ceramic matrix, exhibits excellent room-temperature ionic conductivity of 1.2 mS cm⁻¹ and high stability with Li metal over 1500 h. When tested in a Li|electrolyte|LiFePO₄ battery, the electrolyte delivers excellent cycling performance and rate capability at room temperature, with a discharge capacity of 137 mAh g⁻¹ over 500 cycles at 1 C. Furthermore, the electrolyte not only exhibits a high Li⁺ transference number of 0.76 but also significantly lowers contact resistance (from 157.8 to 2.1 Ω) relative to electrodes. When used in a battery with a high-voltage LiNi_0.8Mn_0.1Co_0.1O₂ cathode, a discharge capacity of 140 mAh g⁻¹ is achieved. These results show the potential of composite polymer-ceramic electrolytes in room-temperature solid-state Li-metal batteries and provide a strategy for designing highly conductive polymer-in-ceramic electrolytes with electrode-compatible interfaces.     

High-Entropy Microdomain Interlocking Polymer Electrolytes for Advanced All-Solid-State Battery Chemistries

All-solid-state polymer electrolytes (ASPEs) with excellent processivity are considered one of the most forward-looking materials for large-scale industrialization. However, the contradiction between improving the mechanical strength and accelerating the ionic migration of ASPEs has always been difficult to reconcile. Herein, a rational concept is raised of high-entropy microdomain interlocking ASPEs (HEMI-ASPEs), inspired by entropic elasticity well-known in polymer and biochemical sciences, by introducing newly designed multifunctional ABC miktoarm star terpolymers into polyethylene oxide for the first time. The tailor-made HEMI-ASPEs possess multifunctional polymer chains, which induce themselves to assemble into micro- and nanoscale dynamic interlocking networks with high topological structure entropy. HEMI-ASPEs achieve excellent toughness, considerable ionic conductivity, an appreciable lithium transference number (0.63), and desirable thermal stability (T_d > 400 °C) for all-solid-state lithium metal batteries. The Li|HEMI-ASPE-Li|Li symmetrical cell shows a stable Li plating/stripping performance over 4000 h, and a LiFePO₄|HEMI-ASPE-Li|Li full cell exhibits a high capacity retention (≈96%) after 300 cycles. This work contributes an innovative design concept introducing high-entropy supramolecular dynamic networks for ASPEs.     

The Sand equation and its enormous practical relevance for solid-state lithium metal batteries

In this work, different Li salt concentrations and ionic conductivities of poly(ethylene oxide)-based solid polymer electrolytes (PEO-based SPEs) are correlated with the performance of LiNi_0.6Mn_0.2Co_0.2O₂ (NMC622)||Li full cells. While the SPEs with different salt concentrations behave similarly in NMC622||Li cells at 60 °C, their influence on the specific capacities is significant at 40 °C. Below a distinct salt concentration, i.e. > 20:1 (EO:Li), a sudden blocking-type polarization appears, indicatable by an almost vertical voltage profile, both in full and in Li||Li symmetric cells. The corresponding time and current density for this polarization-type is shown to mathematically fit with the Sand equation, which subsequently allows calculation of D_Li⁺. According this relation, lack of Li⁺ in the electrolyte close to the electrode surface can be concluded to be the origin of this polarization, but is shown to appear only for “kinetically limiting” conditions e.g. above a threshold current density, above a threshold SPE thickness and/or below a threshold salt concentration (ionic conductivity), i.e. at mass transfer limiting conditions. With the support of this relation, maximal applicable current densities and/or SPE thicknesses can be calculated and predicted for SPEs.     

Li+‐Containing,Continuous Silica Nanofibers for High Li+ Conductivity in Composite Polymer Electrolyte

Solid‐state electrolytes have recently attracted significant attention toward safe and high‐energy lithium chemistries. In particular, polyethylene oxide (PEO)‐based composite polymer electrolytes (CPEs) have shown outstanding mechanical flexibility and manufacturing feasibility. However, their limited ionic conductivity, poor electrochemical stability, and insufficient mechanical strength are yet to be addressed. In this work, a novel CPE supported by Li⁺‐containing SiO₂ nanofibers is developed. The nanofibers are obtained via sol–gel electrospinning, during which lithium sulfate is in situ introduced into the nanofibers. The uniform doping of Li₂SO₄ in SiO₂ nanofibers increases the Li⁺ conductivity of SiO₂, generates mesopores on the surface of SiO₂ nanofibers, and improves the wettability between SiO₂ and PEO. As a result, the obtained SiO₂/Li₂SO₄/PEO CPE yields high Li⁺ conductivity (1.3 × 10^?4 S cm^?1 at 60 °C, ≈4.9 times the Li₂SO₄‐free CPE) and electrochemical stability. Furthermore, the all‐solid‐state LiFePO₄‐Li full cell demonstrates stable cycling with high capacities (over 80 mAh g^?1, 50 cycles at C/2 at 60 °C). The Li⁺‐containing mesoporous SiO₂ nanofibers show great potential as the filler for CPEs. Similar methods can be used to incorporate Li salts into other filler materials for CPEs.     

Solid-State Electrolyte Design for Lithium Dendrite Suppression

All-solid-state Li metal batteries have attracted extensive attention due to their high safety and high energy density. However, Li dendrite growth in solid-state electrolytes (SSEs) still hinders their application. Current efforts mainly aim to reduce the interfacial resistance, neglecting the intrinsic dendrite-suppression capability of SSEs. Herein, the mechanism for the formation of Li dendrites is investigated, and Li-dendrite-free SSE criteria are reported. To achieve a high dendrite-suppression capability, SSEs should be thermodynamically stable with a high interface energy against Li, and they should have a low electronic conductivity and a high ionic conductivity. A cold-pressed Li₃N–LiF composite is used to validate the Li-dendrite-free design criteria, where the highly ionic conductive Li₃N reduces the Li plating/stripping overpotential, and LiF with high interface energy suppresses dendrites by enhancing the nucleation energy and suppressing the Li penetration into the SSEs. The Li₃N–LiF layer coating on Li₃PS₄ SSE achieves a record-high critical current of >6 mA cm⁻² even at a high capacity of 6.0 mAh cm⁻². The Coulombic efficiency also reaches a record 99% in 150 cycles. The Li₃N–LiF/Li₃PS₄ SSE enables LiCoO₂ cathodes to achieve 101.6 mAh g⁻¹ for 50 cycles. The design principle opens a new opportunity to develop high-energy all-solid-state Li metal batteries.     

Tape-Casting Li0.34La0.56TiO3 Ceramic Electrolyte Films Permit High Energy Density of Lithium-Metal Batteries

Ceramic oxide electrolytes are outstanding due to their excellent thermostability, wide electrochemical stable windows, superior Li-ion conductivity, and high elastic modulus compared to other electrolytes. To achieve high energy density, all-solid-state batteries require thin solid-state electrolytes that are dozens of micrometers thick due to the high density of ceramic electrolytes. Perovskite-type Li_0.34La_0.56TiO₃ (LLTO) freestanding ceramic electrolyte film with a thickness of 25 µm is prepared by tape-casting. Compared to a thick electrolyte (>200 µm) obtained by cold-pressing, the total Li ionic conductivity of this LLTO film improves from 9.6 × 10⁻⁶ to 2.0 × 10⁻⁵ S cm⁻¹. In addition, the LLTO film with a thickness of 25 µm exhibits a flexural strength of 264 MPa. An all-solid-state Li-metal battery assembled with a 41 µm thick LLTO exhibits an initial discharge capacity of 145 mAh g⁻¹ and a high capacity retention ratio of 86.2% after 50 cycles. Reducing the thickness of oxide ceramic electrolytes is crucial to reduce the resistance of electrolytes and improve the energy density of Li-metal batteries.     

In Situ Construction of a LiF-Enriched Interface for Stable All-Solid-State Batteries and its Origin Revealed by Cryo-TEM

The application of solid polymer electrolytes (SPEs) is still inherently limited by the unstable lithium (Li)/electrolyte interface, despite the advantages of security, flexibility, and workability of SPEs. Herein, the Li/electrolyte interface is modified by introducing Li₂S additive to harvest stable all-solid-state lithium metal batteries (LMBs). Cryo-transmission electron microscopy (cryo-TEM) results demonstrate a mosaic interface between poly(ethylene oxide) (PEO) electrolytes and Li metal anodes, in which abundant crystalline grains of Li, Li₂O, LiOH, and Li₂CO₃ are randomly distributed. Besides, cryo-TEM visualization, combined with molecular dynamics simulations, reveals that the introduction of Li₂S accelerates the decomposition of N(CF₃SO₂)₂⁻ and consequently promotes the formation of abundant LiF nanocrystals in the Li/PEO interface. The generated LiF is further verified to inhibit the breakage of C O bonds in the polymer chains and prevents the continuous interface reaction between Li and PEO. Therefore, the all-solid-state LMBs with the LiF-enriched interface exhibit improved cycling capability and stability in a cell configuration with an ultralong lifespan over 1800 h. This work is believed to open up a new avenue for rational design of high-performance all-solid-state LMBs.     

PAN–PEO solid polymer electrolytes with high ionic conductivity

The transparent and flexible solid polymer electrolytes (SPEs) are fabricated from polyacrylonitrile–polyethylene oxide (PAN–PEO) copolymer. The formation of the copolymer is confirmed by Fourier-transform infrared spectroscopy (FTIR) and Gel permeation chromatography (GPC) measurements. The effects of acrylonitrile (AN) wt% content and M_n(PEO) on ionic conductivity are investigated by alternating current (ac) impedance spectroscopy. By controlling and adjusting the AN wt% content and doping PEO with high molecular weight, the ionic conductivity of SPEs is optimized. The ionic conductivity of PAN–PEO solid polymer electrolytes is found to be high 6.79 × 10⁻⁴ S cm⁻¹ at 25 °C with an [EO]/[Li] ratio of about 10, and are electrochemically stable up to about 4.8 V versus Li/Li⁺. The conductivity and interfacial resistance remain almost constant even at 80 °C.     

Composite Solid Electrolyte with Continuous and Fast Organic–Inorganic Ion Transport Highways Created by 3D Crimped Nanofibers@functional Ceramic Nanowires

A 3D crimped sulfonated polyethersulfone-polyethylene oxide(C-SPES/PEO) nanofiber membrane and long-range lanthanum cobaltate(LaCoO₃) nanowires are collectively doped into a PEO matrix to acquire a composite solid electrolyte (C-SPES-PEO-LaCoO₃) for all-solid-state lithium metal batteries(ASSLMBs). The 3D crimped structure enables the fiber membrane to have a large porosity of 90%. Therefore, under the premise of strongly guaranteeing the mechanical properties of C-SPES-PEO-LaCoO₃, the ceramic nanowires conveniently penetrated into the 3D crimped SPES nanofiber without being blocked, which can facilitate fast ionic conductivity by forming 3D continuous organic–inorganic ion transport pathways. The as-prepared electrolyte delivers an excellent ionic conductivity of 2.5 × 10⁻⁴ S cm⁻¹ at 30 °C. Density functional theory calculations indicate that the LaCoO₃ nanowires and 3D crimped C-SPES/PEO fibers contribute to Li⁺ movement. Particularly, the LiFePO₄/C-SPES-PEO-LaCoO₃ /Li and NMC811/C-SPES-PEO-LaCoO₃/Li pouch cell have a high initial discharge specific capacity of 156.8 mAh g⁻¹ and a maximum value of 176.7 mAh g⁻¹, respectively. In addition, the universality of the penetration of C-SPES/PEO nanofibers to functional ceramic nanowires is also reflected by the stable cycling performance of ASSLMBs based on the electrolytes, in which the LaCoO₃ nanowires are replaced with Gd-doped CeO₂ nanowires. The work will provide a novel approach to high performance solid-state electrolytes.     

Low-Temperature Fabrication of Bulk-Type All-Solid-State Lithium-Ion Battery Utilizing Nanosized Garnet Solid Electrolytes

Garnet-type Li₇La₃Zr₂O₁₂ (LLZ) materials are attracting attention as solid electrolytes (SEs) in oxide-based all-solid-state batteries (ASSBs) owing to their high ionic conductivity. Although the electrochemical stability of LLZ against Li metal is demonstrated with possible high energy density, high-temperature sintering above 1000 °C, which is required to achieve high Li-ion conductivity, results in the formation of insulating impurities at the electrode–electrolyte interfaces. Here, nanosized fine-particle samples of Ta-substituted Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZT) are successfully prepared at a remarkably low temperature of 400 °C utilizing an amorphous precursor oxide. The dense LLZT SE sintered by hot pressing at 500 °C shows room-temperature Li-ion conductivity of 1.03 × 10⁻⁴ S cm⁻¹ without any additives. In addition, the bulk-type NCM–graphite full battery cell fabricated with the LLZT fine particles through a hot-pressing sintering method at 550 °C exhibits a good charge–discharge performance at room temperature with the bulk-type areal discharge capacity of 0.831 mAh cm⁻². The nanosized garnet SE strategy demonstrated in this study paves the way for the formation of oxide-based ASSBs by low-temperature sintering.     

Li‐Ion Cooperative Migration and Oxy‐Sulfide Synergistic Effect in Li14P2Ge2S16−6xOx Solid‐State‐Electrolyte Enables Extraordinary Conductivity and High Stability

Critical to the development of all‐solid‐state lithium‐ion batteries technology are novel solid‐state electrolytes with high ionic conductivity and robust stability under inorganic solid‐electrolyte operating conditions. Herein, by using density functional theory and molecular dynamics, a mixed oxygen‐sulfur‐based Li‐superionic conductor is screened out from the local chemical structure of β‐Li₃PS₄ to discover novel Li₁₄P₂Ge₂S₈O₈ (LPGSO) with high ionic conductivity and high stability under thermal, moist, and electrochemical conditions, which causes oxygenation at specific sites to improve the stability and selective sulfuration to provide an O‐S mixed path by Li‐S/O structure units with coordination number between 3 and 4 for fast Li‐cooperative conduction. Furthermore, LPGSO exhibits a quasi‐isotropic 3D Li‐ion cooperative diffusion with a lesser migration barrier (≈0.19 eV) compared to its sulfide‐analog Li₁₄P₂Ge₂S₁₆. The theoretical ionic conductivity of this conductor at room temperature is as high as ≈30.0 mS cm^?1, which is among the best in current solid‐state electrolytes. Such an oxy‐sulfide synergistic effect and Li‐ion cooperative migration mechanism would enable the engineering of next‐generation electrolyte materials with desirable safety and high ionic conductivity, for possible application in the near future.     

Effective Suppression of Lithium Dendrite Growth Using a Flexible Single‐Ion Conducting Polymer Electrolyte

A novel single‐ion conducting polymer electrolyte (SIPE) membrane with high lithium‐ion transference number, good mechanical strength, and excellent ionic conductivity is designed and synthesized by facile coupling of lithium bis(allylmalonato) borate (LiBAMB), pentaerythritol tetrakis (2‐mercaptoacetate) (PETMP) and 3,6‐dioxa‐1,8‐octanedithiol (DODT) in an electrospun poly(vinylidienefluoride) (PVDF) supporting membrane via a one‐step photoinitiated in situ thiol–ene click reaction. The structure‐optimized LiBAMB‐PETMP‐DODT (LPD)@PVDF SIPE shows an outstanding ionic conductivity of 1.32 × 10^?3 S cm^?1 at 25 °C, together with a high lithium‐ion transference number of 0.92 and wide electrochemical window up to 6.0 V. The SIPE exhibits high tensile strength of 7.2 MPa and elongation at break of 269%. Due to these superior performances, the SIPE can suppress lithium dendrite growth, which is confirmed by galvanostatic Li plating/stripping cycling test and analysis of morphology of Li metal electrode surface after cycling test. Li|LPD@PVDF|Li symmetric cell maintains an extremely stable and low overpotential without short circuiting over the 1050 h cycle. The Li|LPD@PVDF|LiFePO₄ cell shows excellent rate capacity and outstanding cycle performance compared to cells based on a conventional liquid electrolyte (LE) with Celgard separator. The facile approach of the SIPE provides an effective and promising electrolyte for safe, long‐life, and high‐rate lithium metal batteries.     

Role of Bicontinuous Structure in Elastomeric Electrolytes for High-Energy Solid-State Lithium-Metal Batteries

Solid-state lithium (Li)-metal batteries (LMBs) are garnering attention as a next-generation battery technology that can surpass conventional Li-ion batteries in terms of energy density and operational safety under the condition that the issue of uncontrolled Li dendrite is resolved. In this study, various plastic crystal-embedded elastomer electrolytes (PCEEs) are investigated with different phase-separated structures, prepared by systematically adjusting the volume ratio of the phases, to elucidate the structure-property-electrochemical performance relationship of the PCEE in the LMBs. At an optimal volume ratio of elastomer phase to plastic-crystal phase (i.e., 1:1), bicontinuous-structured PCEE, consisting of efficient ion-conducting, plastic-crystal pathways with long-range connectivity within a crosslinked elastomer matrix, exhibits exceptionally high ionic conductivity (≈10⁻³ S cm⁻¹) at 20 °C and excellent mechanical resilience (elongation at break ≈ 300%). A full cell featuring this optimized PCEE, a 35 µm thick Li anode, and a high loading LiNi_0.83Mn_0.06Co_0.11O₂ (NMC-83) cathode delivers a high energy density of 437 Wh kg_{anode+cathode+electrolyte}⁻¹. The established structure–property–electrochemical performance relationship of the PCEE for solid-state LMBs is expected to inform the development of the elastomeric electrolytes for various electrochemical energy systems.     

Recent developments in garnet based solid state electrolytes for thin film batteries

This paper reviews the current status of, and new progress in, the field of solid state electrolytes (SSE) for lithium ion batteries. In addition to a review of current technologies, we are also presenting our novel results on pulsed laser processing of garnet based SSEs, specifically Li₇La₃Zr₂O₁₂ (LLZO). LLZO powders with a tetragonal structure were prepared by a sol–gel technique, then a pulsed laser annealing process was employed to covert the powders to cubic LLZO without any loss of lithium. The tetragonal LLZO exhibited a Li ion conductivity of 1.8 × 10⁻⁷ S/cm, whereas the laser annealed cubic LLZO showed a Li ion conductivity of 1.0×10⁻⁴ S/cm at room temperature. A systematic study of the effect of pulsed laser annealing (PLA) on the crystal structure, morphology, composition, and ionic conductivity of LLZO was performed via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS) measurements. These results demonstrate that PLA is a powerful processing technique for synthesizing the high ionic conductivity cubic phase of LLZO at relatively low temperatures, as compared to conventional methods.     

Hollow-Particles Quasi-Solid-State Electrolytes with Biomimetic Ion Channels for High-Performance Lithium-Metal Batteries

Solid-state electrolytes (SSEs) are the core material of solid-state lithium metal batteries (SLMBs), which are being researched urgently owing to their high energy and safety. Both high ionic conductivity and excellent cycling stability remain the primary goal of solid-state electrolytes. Herein, inspired by K⁺/Na⁺ ion channels in cell membrane of eukaryotes, a novel hollow UiO-66 with biomimetic ion channels based on quasi-solid-state electrolytes (QSSEs) is designed. The hollow UiO-66 spheres containing biomimetic ion channels can spontaneously combine anions and incorporate more lithium ions, creating improved ionic conductivity (1.15 × 10⁻³ S cm⁻¹) and lithium-ion transference number (0.70) at room temperature. The long-term cycling of symmetric batteries and COMSOL simulations demonstrate that this biomimetic strategy enables uniform ion flux to suppress Li dendrites. Furthermore, the Li metal full cells paired with LiFePO₄ cathode exhibit excellent cycling stability and rate performance. Consequently, the strategy of designing biomimetic QSSEs opens up a new path for developing high-performance electrolytes for SLMBs.     

A Metal–Organic‐Framework‐Based Electrolyte with Nanowetted Interfaces for High‐Energy‐Density Solid‐State Lithium Battery

Solid‐state batteries (SSBs) are promising for safer energy storage, but their active loading and energy density have been limited by large interfacial impedance caused by the poor Li⁺ transport kinetics between the solid‐state electrolyte and the electrode materials. To address the interfacial issue and achieve higher energy density, herein, a novel solid‐like electrolyte (SLE) based on ionic‐liquid‐impregnated metal–organic framework nanocrystals (Li‐IL@MOF) is reported, which demonstrates excellent electrochemical properties, including a high room‐temperature ionic conductivity of 3.0 × 10^‐4 S cm^‐1, an improved Li⁺ transference number of 0.36, and good compatibilities against both Li metal and active electrodes with low interfacial resistances. The Li‐IL@MOF SLE is further integrated into a rechargeable Li|LiFePO₄ SSB with an unprecedented active loading of 25 mg cm^‐2, and the battery exhibits remarkable performance over a wide temperature range from ?20 up to 150 °C. Besides the intrinsically high ionic conductivity of Li‐IL@MOF, the unique interfacial contact between the SLE and the active electrodes owing to an interfacial wettability effect of the nanoconfined Li‐IL guests, which creates an effective 3D Li⁺ conductive network throughout the whole battery, is considered to be the key factor for the excellent performance of the SSB.     

Aliphatic Polycarbonate‐Based Solid‐State Polymer Electrolytes for Advanced Lithium Batteries: Advances and Perspective

Conventional liquid electrolytes based lithium‐ion batteries (LIBs) might suffer from serious safety hazards. Solid‐state polymer electrolytes (SPEs) are very promising candidate with high security for advanced LIBs. However, the quintessential frailties of pristine polyethylene oxide/lithium salts SPEs are poor ionic conductivity (≈10⁻⁸ S cm⁻¹) at 25 °C and narrow electrochemical window (<4 V). Many innovative researches are carried out to enhance their lithium‐ion conductivity (10⁻⁴ S cm⁻¹ at 25 °C), which is still far from meeting the needs of high‐performance power LIBs at ambient temperature. Therefore, it is a pressing urgency of exploring novel polymer host materials for advanced SPEs aimed to develop high‐performance solid lithium batteries. Aliphatic polycarbonate, an emerging and promising solid polymer electrolyte, has attracted much attention of academia and industry. The amorphous structure, flexible chain segments, and high dielectric constant endow this class of polymer electrolyte excellent comprehensive performance especially in ionic conductivity, electrochemical stability, and thermally dimensional stability. To date, many types of aliphatic polycarbonate solid polymer electrolyte are discovered. Herein, the latest developments on aliphatic polycarbonate SPEs for solid‐state lithium batteries are summarized. Finally, main challenges and perspective of aliphatic polycarbonate solid polymer electrolytes are illustrated at the end of this review.     

Conductivite ionique des oxydes Li8MO6 (M = Ce,Hf)

The electrical conductivity of the oxides Li₈CeO₆ and Li₈HfO₆, which are thermodynamically stable against Li (1), has been studied under oxygen atmosphere in the temperature range between room temperature and 200°C. As for Li₈ZrO₆ and Li₈SnO₆ (2), the materials can be considered as solid electrolytes with medium conductivity. The interpretation of the results, considering the Ca²⁺ ions as impurities, are in agreement with those based on the diffusion mechanisms of the Li⁺ ions recently established by ⁷Li NMR in isostructural oxides by Simpson et al. (3).     

The effects of salt concentration on ion state and conductivity in comb cross-linked polymer electrolytes

A new type of comb cross-linked polyurethane/acrylate polymer was designed. The polymer has sparse network structure with many long comb molecule chains. A new solid polymer electrolyte (SPE) was prepared based on the polymer. The salt in the solid polymer electrolytes has different existent states with different salt contents. With increase of salt concentration, the ion pairing gradually becomes important existent form of salt, and T _g value of the SPE increases. At the same time, ionic conductivity increases rapidly. It is possible to design novel solid polymer electrolytes with high ionic conductivity to meet practical application by comb cross-linked polymer with high salt content.