Long Cycle Life All-Solid-State Batteries Enabled by Medium Nanosized Catholytes

Poor interfacial contact in a solid-state cathode is a major challenge in the development of high specific energy and long cycle life all-solid-state batteries (ASSBs). Herein, the influence of catholyte size on the electrochemical performance of ASSBs is inspected, and the size of Li₆PS₅Cl (LPSCl) catholyte is tuned for optimizing the ionic conduction and active material utilization in cathode. A medium nanosized LPSCl catholyte not only forms fast ionic transport network throughout the cathode but also provides high specific interfacial area to alleviate the electrochemo-mechanical coupling effect and thus benefits comprehensive improvement of electrochemical performance in ASSBs. As a result, the Li–In||NCM811 ASSBs with ∼500 nm LPSCl catholyte display an ultralong cycle life of 2400 cycles without much capacity decay at a high rate of 15C. This work confirms that optimization of catholyte size is a significant step toward the practical application of all-solid-state pouch cells.