Abstract:

Sulfide is one of the most promising solid electrolytes to realize all-solid-state batteries for its superior ionic conductivity and excellent mechanical properties. The Si-based anode with a high theoretical specific capacity (3759 mA·h/g, ～10 times that of graphite) is a promising candidate to further increase the energy density of sulfide all-solid-state for wide applications. Moreover, the combination of Si-based anode and sulfide solid electrolyte can be used to improve the interfacial solid-solid contact and ion transportation using mechanically soft sulfides to accommodate huge volume expansion of silicon-based anodes, thus achieving a high capacity and suppressing repetitive the solid-electrolyte-interphase formation to realize long-cycle high-energy density batteries. However, despite the promising advantages of Si-based anode sulfide all-solid-state batteries, effective characterization methods and in-depth understanding of basic scientific issues in this field are still missing, presenting poor full-battery performance, fast decay of capacity, and low energy density. This paper summarizes the related work/progress in this field and elaborates the three types of Si-based anode sulfide all-solid-state batteries (pellet, wet coating, and thin film). Moreover, the key factors influencing battery performances, such as Si particle size, external stress, appropriate cut-off voltage, and Young's modulus of sulfide electrolytes, are comprehensively analyzed. Finally, the current problems and challenges in this field are proposed for its benign development in the future.

Key words: sulfide, solid-state electrolyte, Si-based anode, all-solid-state batteries