In Situ Carbonization Phosphorylated Chitosan for Constructing High-Performance Silicon–Carbon Anodes: Interfacial Stability and Rapid Lithium Storage

Carrying out charge–discharge cycles at high rates is limited by silicon’s poor electrical conductivity and significant volume expansion, making it difficult to fully utilize the high capacity advantage of silicon-based anodes. On this occasion, we propose an effective strategy to stabilize silicon–carbon anodes and enhance rate capability by functionalizing chitosan with phosphoric acid to obtain a chitosan-derived binder, followed by casting the electrode and in situ carbonization. This in situ carbonization process simultaneously constructs nitrogen- and phosphorus-rich carbon networks to enhance electron/ion transport, while also forming robust silicon–carbon interface bonds (Si–O–P, Si–O–C, Si–N–C). This ensures stable surface contact during cycling and mitigates volume expansion. This one-step-formed silicon working electrode exhibits a high silicon loading of up to 86%, demonstrating high initial Coulombic efficiency (87.42%), stable cycling performance (82.3% capacity retention after 600 cycles at 4 A g–1), and outstanding rate capability (1547 mAh g–1 at 5 A g–1). This work provides a viable modification strategy and production application prospects for high-performance silicon-based anodes in next-generation lithium-ion batteries.