Polarization reduction through P-doped carbon coatings for fast-charging graphite anodes

Fast-charging capability has become a critical requirement for lithium-ion batteries (LIBs) especially for electric vehicles. However, conventional graphite anodes suffer from sluggish lithium diffusion kinetics and significant interfacial polarization under high-rate conditions, leading to poor rate performance. Herein, graphite secondary particles with P-doped hard carbon coating were prepared successfully, via spray drying granulation and subsequent pyrolysis. Spray drying granulation enhances the isotropy of graphite and shortens the Li⁺ transport pathway, while the P-doped hard carbon layer provides an expanded interlayer spacing to accelerate Li⁺ diffusion and alleviate concentration polarization. Furthermore, the optimized electronic structure of P-doped carbon layer promotes the formation of a stable SEI film rich in LiF and Li2CO3, and lowers the interfacial charge transfer resistance, thus mitigating the electrochemical polarization. As a result, the optimized anode exhibits a capacity retention of 73.2% at 6 C, and 82.7% after 600 cycles at 1 C, significantly outperforming the pristine graphite. This work demonstrates a scalable and effective strategy for mitigating interfacial polarization of graphite anodes, providing practical guidance for the industrial advancement of fast-charging LIBs anodes.