Multiphase nanocomposite prelithiation agents for service life lithium replenishment in Si-based Li-ion batteries

High-energy density lithium-ion batteries (LIBs) using Si-based anodes are expected to dominate the lithium-ion power battery market in the near future. However, the Si anode suffers from continuous capacity degradation during initial and subsequent cycles. Prelithiation agents can effectively replenish lithium and enhance battery capacity, while currently investigated cathode prelithiation agents generally only prelithiate at the initial cycle. Herein, we have developed a multiphase nanocomposite prelithiation agent (MNCP) on the basis of two distinct mechanisms-oxygen oxidation and conversion reaction-aiming to provide service life lithium replenishment for Si-based LIBs. MNCP presents several tunable delithiation plateaus to prelithiate anodes in the initial and extending cycles with exceeding 600 milliampere-hours per gram without gas generation. This work emphasizes a mechanism-based design strategy for functional prelithiation agents, aiming to comprehensively optimize the performance of advanced LIBs.