Status, promises, and challenges of nanocomposite solid-state electrolytes for safe and high performance lithium batteries

All-solid-state Li batteries (ASSLBs) are well recognized as potentially high energy density, safe systems for future energy storage. The development of solid-state electrolytes is one of the most crucial steps for ASSLBs. Nanocomposite solid-state electrolytes (CSSEs)—which contain both polymer electrolytes and nanoscale inorganic fillers (such as inorganic solid electrolyte filler)—have attracted tremendous interest with their good processability, flexibility, and reasonable ionic conductivity. In this review article, we will discuss the recent progress, design principles, and challenges of CSSEs for ASSLBs.