In-situ gradient assembled thin-layered nano-template with enhanced NCo bonds regulated honeycomb-like micron Si anode for highly stable lithium-ion batteries

Applying hard carbon nano-template (HCN) on micron silicon is a potential strategy to exploit next-generation lithium-ion battery (LIB) anodes. However, achieving a balance in performance and stability under high stress during cycling is still a huge challenge. Herein, we developed an in - situ gradient assembly strategy to obtain three kinds of N,Co co-doped thin-layered HCN (THCN N,Co ) on the surface of honeycomb-like micron porous silicon (HMPSi) by regulating the thin-layer thickness, pore structure and specific chemical bonds. The results show that the relatively thin-layered HCN (RTHCN N,Co ) with enhanced Pyrrolic N Co bonds can effectively adjust the high stress, optimize the ion transport paths and improve the electrochemical activity of HMPSi, resulting in excellent cycling stability at large current density. Specially, the HMPSi@RTHCN N,Co anode displayed a high reversible capacity of 883.5 mAh g −1 after 600 cycles at 1 A g −1 and 446.2 mAh g −1 after 1000 cycles at 3 A g −1 . Moreover, the full cell using HMPSi@RTHCN N,Co anode and LiFePO 4 cathode exhibited a high capacity retention of 92.8% after 100 cycles. Our work provides a valuable surface nano-engineering strategy to regulate the structural stability and electrochemical activity of micron Si anode for long-term stable LIB application.