In all-solid lithium metal batteries, sulfide electrolytes offer superior ion conductivity. Nevertheless, they also confront significant challenges, such as the formation of internal dendrites and instability in lithium and humid air. In order to overcome these issues, a sulfide composite electrolyte has been prepared by mixing polyethylene oxide polymers with air-stable inorganic sulfide, Li 4 SnS 4 , which can achieve good chemical and electrochemical stability. Meanwhile, the introduced Li 4 SnS 4 can facilitate the movement of Li + ions in the composite electrolyte, which exhibits an elevated ion conductivity up to 2.55 × 10 −5 S cm −1 . Graphical Abstract
Lihao Zheng,Juntao Shi,Gaoya Ren,Tiantian Tang,Yefeng Yang,Shenghui Shen,Zhujun Yao
Sulfide solid electrolytes have emerged as highly promising candidates for an all-solid-state battery, while phosphorus-free compounds with air stability have not gotten enough attention. In this study, we focus on an air-stable compound, Li4SnS4, whose structure can be adjusted by Bi3+ doping through the combination of a two-step ball milling method and thermal annealing. The successful substitution of Sn4+ by Bi3+ with lower valence and larger ionic radius results in the enhancement of Li+ concentration in electrolytes and lattice volume, benefiting the Li+ migration. Therefore, the modified glass-ceramic Li4.025Sn0.975Bi0.025S4 exhibits an ionic conductivity of 1.35 × 10–4 S cm–1 at room temperature, which is twice as high as that of pure Li4SnS4. Moreover, the soft acid characteristic of Bi3+ can further ensure the air stability of Li4SnS4 based on the hard and soft acid and base theory. The findings revealed from this research provide a potential avenue for improving the performance of air-stable Li4SnS4 solid-state electrolytes for future large-scale applications.
High ionic conductivity, low grain boundary impedance, and stable electrochemical property have become the focus for all-solid-state lithium–sulfur batteries (ASSLSB). One of the approaches is to promote the rapid diffusion of lithium ions by regulating the chemical bond interactions within the framework. The structure control of P 5+ substitution for Sn 4+ on lithium-ion transport was explored for a series of Li 3 PS 4 –Li 4 SnS 4 glass–ceramic electrolytes. Results showed that the grain boundary impedance of the glass electrolyte was reduced after heat treatments. The formation of LiSnPS microcrystals, a good superionic conductor, was detected by X-ray diffraction tests. Electrochemical experiments obtained the highest conductivity of 29.5 S cm −1 at 100°C and stable electrochemical window from –0.1 to 5 V at 25°C. In addition, the cell battery was assembled with prepared electrolyte, which is promoted as a candidate solid electrolyte material with improved performance for ASSLSB.
危险品化学品经营许可证（带存储）