Application of bacterial cellulose-based nanomaterials in solid electrolytes for high-performance lithium metal batteries

Solid electrolytes are regarded as one of the important materials for solving the problems of lithium dendrite growth and safety hazards in lithium metal batteries (LMBs) because of their excellent chemical and electrochemical stability as well as outstanding flame resistance. However, the application of solid electrolytes in LMBs still faces key challenges such as high interfacial resistance, poor mechanical properties, high cost, and difficulties in mass production. In this regard, a natural and renewable nanomaterial-bacterial cellulose (BC) has received considerable attention in recent years, as its specific advantages can offer solutions to these challenges: its tunable molecular structure enables customized ion transport and enhanced interfacial compatibility, effectively reducing interfacial resistance; its inherent mechanical robustness helps improve the structural stability of the electrolyte; meanwhile, the abundance, environmental friendliness, and cost-effectiveness of BC also provide a feasible foundation for large-scale production and application. This review focuses on the emerging role of BC with its unique three-dimensional nanofibrillar network as a versatile platform for engineering advanced solid electrolytes. We begin by outlining the structural characteristics and intrinsic properties of BC that underpin its functionality in electrochemical systems, including its high crystallinity, exceptional mechanical robustness, and tunable surface chemistry. Subsequently, we systematically explore how BC serves as a multifunctional platform in composite solid-state electrolytes, reinforcing mechanical strength to suppress lithium dendrites, ensuring continuous ion conduction, and enhancing interfacial stability through strategies like chemical modification and hybridization. Finally, we provide perspectives on the current challenges and future research directions necessary to translate BC-based electrolytes from promising laboratory prototypes to commercially viable components in next-generation, high-performance, and safe LMBs.