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Gel polymer electrolytes (GPEs) are intrinsically advantageous over rigid inorganic ones due to their easy processability and scalability. However, in terms of poor mechanical strength, GPEs can hardly satisfy the requirement of practical Li metal batteries. Herein, a novel one‐dimensional Cu‐metal–organic framework (MOF)‐filler‐reinforced GPE with the merits of high mechanical strength and high ionic conductivity is developed. When such GPE is used in Li symmetrical cells, small and stable Li‐plating/stripping overpotentials (~50 mV) can be maintained over 350 h at.3 mA/cm2. Benefitting from the above MOF‐filler‐reinforced GPE, a full cell with the Li metal anode and LiFePO4 cathode presents a stable cycling performance with a low capacity decay rate of.004% per cycle over 800 cycles at 1 C. [ABSTRACT FROM AUTHOR]

All‐solid‐state lithium batteries (ASSBs) have the potential to trigger a battery revolution for electric vehicles due to their advantages in safety and energy density. Screening of various possible solid electrolytes for ASSBs has revealed that garnet electrolytes are promising due to their high ionic conductivity and superior (electro)chemical stabilities. However, a major challenge of garnet electrolytes is poor contact with Li‐metal anodes, resulting in an extremely large interfacial impedance and severe Li dendrite propagation. Herein, an innovative surface tension modification method is proposed to create an intimate Li | garnet interface by tuning molten Li with a trace amount of Si3N4 (1 wt%). The resultant Li‐Si‐N melt can not only convert the Li | garnet interface from point‐to‐point contact to consecutive face‐to‐face contact but also homogenize the electric‐field distribution during the Li stripping/depositing process, thereby significantly decreasing its interfacial impedance (1 Ω cm2 at 25 °C) and improving its cycle stability (1000 h at 0.4 mA cm−2) and critical current density (1.8 mA cm−2). Specifically, the all‐solid‐state full cell paired with a LiFePO4 cathode delivered a high capacity of 145 mAh g−1 at 2 C and maintained 97% of the initial capacity after 100 cycles at 1 C. [ABSTRACT FROM AUTHOR]

Solid-state Li-ion batteries (SSBs) are believed the new future of electrochemical energy storage, while the solid electrolyte membrane is the core part. The development of new electrolyte membrane with easy densification, high stability and high conductivity is crucial for the widespread application of SSBs. In this study, tuning the conductivity and sintering behavior of perovskite-type La 2/3-x Li 3x TiO 3 (LLTO) membranes through a co-doping strategy was proposed and systematically investigated. Specifically, the membranes with the nominal compositions of Li 0.33-y+x La 0.557-x M x Ti 1-y N y O 3 (M = Sr, Ba, Ca, N = Ta) were designed and investigated. The results demonstrated that replacement of La3+ by smaller Ca2+ decreased the bulk Li+ conductivity while substitution of La3+ by Sr2+ or Ba2+ with larger ionic radii increased the bulk Li+ conductivity. Besides, Ta5+ and Sr2+ co-doped LLTO with optimized Ta/Sr molar ratio could improve the membrane densification involving the relative density and grain size. Accordingly, a high total Li+ conductivity (1.4 × 10−4 S cm−1) with low electronic conductivity (3.2 × 10−8 S cm−1) could be achieved, and the as-prepared Li 0.33 La 0.457 Sr 0.1 Ti 0.9 Ta 0.1 O 3 membrane presented prominent electrochemical performance with a high capacity retention (89%) and Coulombic efficiency of 97% for 80 cycles, thus promised co-doping strategy for developing superior perovskite Li-ion conducting membranes for SSBs. • Perovskite Li 0.33-y+x La 0.557-x M x Ti 1-y N y O 3 (M = Sr, Ba, Ca, N = Ta) membranes were prepared systematically. • Ta5+ and Sr2+ co-doped membrane exhibited high membrane densification and low grain boundary resistance. • Li 0.33 La 0.457 Sr 0.1 Ti 0.9 Ta 0.1 O 3 showed a total Li-ion conductivity of 1.4 × 10−4 S cm−1 at room temperature. • The membrane could be cycled in solid-state Li-ion battery with a capacity retention of 89% after 80 cycles. [ABSTRACT FROM AUTHOR]

Rigid‐flexible coupled composite polymer electrolytes (CPEs, e.g., polyethylene oxide/Li6.4La3Zr1.4Ta0.6O12, PEO/LLZTO) hold the promise of integrating the respective merits of organic polymer electrolyte and inorganic ceramic fillers to achieve better all‐solid‐state batteries (ASSBs), but commonly suffer from poor synergistic effect owing to the ionically/electronically resistive layer on the ceramic surface. Representatively, the Li2CO3 passivation layer‐isolated LLZTO not only contributes minimally to the Li+ conduction in PEO/LLZTO CPE, but also narrows the available electrochemical window. Herein, an interfacial reconstruction strategy is disclosed based on mild liquid‐phase chemical reaction and subsequent self‐assembly, allowing the detrimental Li2CO3 to fully react with succinic anhydride (SA), and simultaneously constructing a robust ultra‐thin lithium succinate (SALi) ionic conductor shell to eradicate its regeneration. Accordingly, the obtained PEO/LLZTO@SALi (PLS) CPE shows a high room‐temperature ionic conductivity (1.2 × 10−4 S cm−1), a wide electrochemical window (4.8 V), a notable Li+ transference number (0.37), as well as nonflammability and exceptional compatibility with Li metal in Li/Li symmetric cells (2000 h at 0.2 mA cm−2). More encouragingly, the Li/PLS CPE/LiFePO4 full ASSB maintains an ultrahigh capacity retention of 84.3% after 1400 cycles at room temperature. This work propels the design of high‐performance CPEs through the interfacial modulation of inorganic ceramic fillers. [ABSTRACT FROM AUTHOR]

Considering significant safety advantages, all solid-state LIBs have attracted considerable attentions as alternative power sources for electric vehicles where safety is a big concern, while the development of solid electrolyte membrane with high lithium-ion conductivity, negligible electron conductivity and high stability is the key challenge. Here, Sr and Sb co-doping strategy was applied to further improve the sintering capability and conductivity properties of Li 7 La 3 Zr 2 O 12 garnet-type electrolytes. Specifically, Li 6.6+x La 3-x Sr x Zr 1.6 Sb 0.4 O 12 (x = 0–0.2) oxides were designed and the physical and electrochemical performance of the various materials were comparatively studied. The results of X-ray diffraction and Raman spectra revealed Li 6.6+x La 3-x Sr x Zr 1.6 Sb 0.4 O 12 (x = 0–0.2) prepared by conventional solid-state reaction was in cubic structure. The introduction of a small amount of Sr into the La sites is beneficial for membrane densification and lithium-ion mobility, turning out high density of 95.1% and ionic conductivity of 8.83 × 10−4 S cm−1 at room temperature. The EIS showed the doping of Sr in La sites resulted in improved conductivity at both grain boundary and the oxide bulk. The batteries consisting of lithium film anode, Li 6.66 La 2.94 Sr 0.06 Zr 1.6 Sb 0.4 O 12 solid electrolyte membrane and LiFePO 4 cathode reached the first discharge capacity of 157 mAh g−1 at 0.1 C between 4.2 and 2.0 V (vs. L/Li+) with capacity retention of 93% after 100 cycles at ambient temperature. These results displayed that the Sr, Sb co-doped LLZO electrolytes are alternative for all solid-state Li-ion batteries. Image 1 • A Sr, Sb co-doping strategy was used to design Li 7 La 3 Zr 2 O 12 electrolyte membrane. • A new garnet-type Li 6.66 La 2.94 Sr 0.06 Zr 1.6 Sb 0.4 O 12 (LLSZSO) membrane was developed. • The LLSZSO shows high ionic conductivity of 8.83 × 10−4 S cm−1 at room temperature. • The capacity of LLSZSO is 146 mAh g−1 with retention rate of 93% after 100 cycles. [ABSTRACT FROM AUTHOR]