Constructing a simple conductive-elastic layer on graphite surfaces for high-rate and long-life lithium-ion batteries

Graphite serves as a pivotal anode material in lithium-ion batteries. However, issues such as the co-embedding of solvent molecules during cycling and rapid capacity degradation at high rates have greatly hampered the practical application and development of graphite materials. Herein, this study proposes a straightforward, cost-effective, and environmentally benign strategy for modifying graphite anodes, with the dual objectives of enhancing high-rate capability and prolonging cycle life. Using water as the primary solvent and polyacrylonitrile as the coating material, a highly conductive, flexible, and strongly bonded polymer cladding layer is designed by combining solid−liquid coating and low-temperature heat treatment technologies. This innovative design not only effectively prevents the co-embedding of solvent molecules and mitigates the volume change of graphite particles during extended cycling, but also successfully constructs a dense and efficient electron transport network on the graphite surface. Leveraging the stability advantages brought by the high electron cloud overlap of C=N bonds (comprising σ bonds and π bonds), the conductivity and structural stability of the material are enhanced. This ultimately results in the successful synthesis of the G@C-PAN core−shell material, which exhibits high-rate performance and exceptional long-cycling stability. The results indicate that the material retains a high specific capacity of 328.12 mAh·g^−1 with 96.18% capacity retention after 250 cycles at 0.5C. Furthermore, it exhibits an impressive specific capacity retention of 97.20% after 500 cycles at 2C. This study presents a sustainable, economically viable, and scalable approach for commercializing high-performance graphite-based lithium-ion batteries.