Recent progress and design principles of nanocomposite solid electrolytes

The electrochemical performance of all-solid-state batteries is largely determined by the physicochemical properties of the solid electrolytes. However, none of a single-type solid electrolyte can meet all practical requirements for all-solid-state batteries, including high ionic conductivity, wide electrochemical window, stable interfacial chemistry, robust mechanical properties, and so on. The nanocomposite solid electrolytes have provided a facile solution to address the above challenges, and great achievements have been made in this field. This review briefly summarizes the recent development of the nanocomposite solid electrolytes, focusing on the fundamentals of ionic charge transfer and chemical evolutions at the heterointerface. With the discussion, we hope to shed light on the rational design of solid electrolytes toward the optimal operational performance of all-solid-state batteries.