Long cycle life all-solid-state batteries enabled by solvent-free approach for sulfide solid electrolyte and cathode films

All-solid-state batteries have been considered as a promising energy storage system due to their high energy density and intrinsic safety. As the key component, sulfide solid electrolytes have attracted enormous attentions benefitting from the high ionic conductivity and small grain boundary resistance. However, fabricating ultrathin sulfide solid electrolyte film to achieve high energy density remains a challenge. Here, we report a strategy to obtain freestanding sulfide solid electrolyte film by hot rolled technology using PTFE and Li6PS5Cl powders. The obtained electrolyte film is 40 mu m with a high ionic conductivity of 8.4 mS cm-1. Meanwhile, we prepared solvent-free cathode (LiNbO3@LiNi0.6Co0.2Mn0.2O2) film using the dry method technology. Herein, the all -solid-state batteries with the dry cathode and electrolyte films deliver a high discharge capacity of 120 mA h g-1 with excellent stability of 86.4 % after 1000 cycles at 1C and excellent rate performance (40 mA h g-1 at 4C) at room temperature. Furthermore, the pouch batteries show outstanding electrochemical performance, indicating po-tential commercial applications of sulfide-based solid-state batteries.

Automated summary

In this study, a freestanding sulfide solid electrolyte film was fabricated using PTFE and Li6PS5Cl powders through hot rolling technology, with a thickness of 40 μm and high ionic conductivity of 8.4 mS cm-1. A solvent-free cathode film (LiNbO3@LiNi0.6Co0.2Mn0.2O2) was also prepared using dry method technology. The all-solid-state batteries with these materials exhibited high discharge capacity (120 mA h g-1) and stability (86.4% retention after 1000 cycles at 1C), as well as excellent rate performance (40 mA h g-1 at 4C) at room temperature. These findings demonstrate the potential commercial applications of sulfide-based solid-state batteries.