Improving electrochemical stability by modifying the Li6PS5Cl entailed with the mixed phase of Li6.4La3Zr1.4Ta0.6O12 composite solid electrolytes for all-solid-state lithium battery applications

All-solid-state lithium batteries (ASSLB) are recognized as one of the next-generation energy storage technologies that can compete with or even surpass the state-of-the-art liquid-based lithium-ion batteries. In this work, Li6PS5Cl (LPSCL) is prepared by a ball-mill vacuum seal sintering process and the phase structure, chemical, morphological and electrochemical properties are characterized. The LPSCL shows an ionic conductivity of 1.06 × 10−3 S/cm at room temperature. However, the Li stripping/plating of Li/LPSCL/Li showed short circuits after 18 cycles, resulting in poor stability versus Li. To improve the conductivity and stability of Li, the LPSCL is modified with Li6.4La3Zr1.4Ta0.6O12 using a simple mixing procedure. The influence of the different mass ratios of LPSCL and Li6.4La3Zr1.4Ta0.6O12 as composite solid electrolytes (CSE) on the electrochemical performance is investigated. The optimized Li/CSE9010/Li cell exposed higher conductivity and Li stability. It can be attributed to this work that the production of mixed oxide with sulfide CSE improves the stability of the electrochemical interface and the atmospheric compatibility.