Recent progress on inorganic composite electrolytes for all-solid-state lithium batteries

To address the low energy density and potential safety issues of modern lithium-ion batteries (LIBs), all-solid-state lithium batteries (ASSLBs) with solid-state electrolytes (SSEs) have emerged as a highly promising option. Among different SSEs, inorganic electrolytes (IEs) are the most probable to replace organic liquid electrolytes because of their relatively high lithium ionic conductivity and wide cell voltage window. Nevertheless, IEs encounter challenges such as elevated interfacial resistance, limited ionic conductivity at room temperature, and air instabilities. Different hybrid solid electrolytes, including organic–inorganic hybrid solid electrolytes (OIHSEs) and inorganic composite electrolytes (ICEs), have been developed to overcome these difficulties. While OIHSEs have been reviewed thoroughly, ICEs have been reviewed rarely, despite their crucial role in the advancement of ASSLBs. This review focuses on the synthesis methodologies, structures, compositions, and electrochemical performance of ICEs, providing a comprehensive overview of the present state-of-art ICEs, with constructive conclusions and perspectives for different ICEs on varied purposes. Ultimately, this review aims to shed light on potential research directions for the designing and building of practical ASSLBs with varying ICEs, thereby promoting the energy storage application of ASSLBs. Graphical abstract The recent advances in “Inorganic composite electrolytes for all-solid-state lithium batteries” were reviewed, with an emphasis on their compositions, synthesis techniques, electrochemical performances, and applications. Several research directions are offered to design and manufacture viable ICEs. Highlights This review provides a comprehensive overview of the present state-of-art inorganic composite electrolytes, with constructive conclusions and perspectives for different ICEs on varied purposes. This review focuses on the synthesis methodologies, structures, compositions, and electrochemical performance of inorganic composite electrolytes in ASSLBs. Discussion The implementation of all-solid-state lithium batteries emerges as a pivotal remedy for addressing the safety concerns and energy density limitations inherent in conventional lithium-ion batteries. The decision between inorganic electrolytes and hybrid solid electrolytes, specifically the relatively unexplored inorganic composite electrolytes, necessitates thorough deliberation and underscores the importance of inter