Bioinspired ceramic-enhanced F/N-doped carbon coating enables high-rate silicon anodes

Silicon is a promising anode for next-generation lithium-ion batteries owing to its ultrahigh specific capacity, low lithiation potential, and natural abundance. However, its low electronic conductivity and severe volume expansion cause rapid capacity fading, and conventional carbon coatings inadequately mitigate this volume change due to inferior mechanical properties, especially under high-rate cycling. To tackle these challenges, inspired by the mineral armor of leaf-cutter ants, a bioinspired ceramic-enhanced carbon coating strategy is proposed for silicon nanosheets (SiNSs). A CrN-enhanced, F/N co-doped carbon coating is synthesized in situ on SiNSs using chromium-based and carbonaceous precursors. The incorporated CrN nanophase mechanically reinforces the carbon matrix, improving its apparent surface modulus and helping accommodate the volume change of silicon nanosheets under high-rate cycling. Meanwhile, the F/N-doped carbon coating contributes to improved interfacial properties and facilitates fast Li⁺ transport. As a result, the resultant Si/CrN/FNC anode delivers a 39% higher apparent surface modulus than Si/C and retains 73% of its capacity after 300 cycles at 10C. This work provides a viable strategy for constructing mechanically reinforced carbon coatings for high-rate silicon anodes.