Cellulose-based solid-state electrolytes for high energy density lithium batteries: insight from ion transport mechanism to coordination structural design

Cellulose-based solid-state electrolyte (Cel-SSEs) has become one of the key material systems for all-solid-state lithium batteries (ASSLBs) due to its bio-recyclability, excellent mechanical strength and intrinsic safety. However, the low room temperature ionic conductivity (10 –4 –10 –3 S cm –1 ), lithium dendrite growth and side reactions caused by poor interface compatibility, as well as difficulties in large-scale preparation have seriously restricted its commercialization process. Herein, the opportunities and challenges faced by cellulose as electrolyte are briefly introduced. The ion transport mechanism for Cel-SSEs is systematically expounded, namely, the synergistic transport of the amorphous-crystalline region, the optimization of Lewis acid-base and the auxiliary regulation of the dynamic hydrogen bond network. Based on the natural logic from micro to macro and from bulk to interface, it is divided into functional group modification, composite system optimization, electrolyte macro structure design and interface structure regulation. The internal logic of each strategy to synergistically improve ionic conductivity and interface stability is systematically revealed. Finally, prospecting future development of Cel-SSEs, it is necessary to develop a simple, efficient and green large-scale preparation technology through multi-scale transmission mechanism analysis, wide temperature range adaptation design and electrode-electrolyte integration, so as to realize an all-solid-state battery system with high energy density and intrinsic safety.