Hierarchically Conformal Li⁺/Electron Conductive and Mechanically Robust Interface Enabling Natural Graphite Anodes for Fast-Charging and Long-Cycling Operation

Lithium-ion batteries have revolutionized global energy storage systems; however, current technologies fall short of meeting fast-charging and long-cycling demands, primarily due to the inadequate rate performance and cycling stability of graphite anode materials. Herein, a surface polarity regulation strategy is proposed to construct a hierarchically conformal Li⁺/electron conductive and mechanically robust interface on natural graphite anodes, consisting of an inner N-doped carbon layer and an outer Li₃PO₄ layer. Various in situ characterizations unravel that an inorganic solid electrolyte interface (SEI) can be derived with great mechanical robustness and superior stability, and this derived SEI with the artificial interface can not only greatly facilitate the de-solvation process as well as Li⁺ and electron transport, but also reduce the strain accumulation and the structural instability, and inhibit the formation of lithium dendrites as well. The as-modified natural graphite anode demonstrates remarkable rate performance with 10 C rate capacity retention of 71.8% to that of 0.1 C rate, and outstanding long-cycle performance with 95.9% capacity retention after 1000 cycles. This surface engineering approach should inspire the development of long-cycle-life and fast-charging anode materials for future lithium-ion batteries.