High Softening Point Isotropic Coating Pitch Prepared by Oxidative Co‐Polymerization for Enhanced Electrochemical Performance of Graphite Anodes

ABSTRACT Coating pitch is an important surface modification material for graphite anodes in lithium‐ion batteries (LIBs), which can significantly enhance the performance of graphite. Currently, developing low‐cost and simple‐process coal‐based coating pitch remains a considerable challenge. To fully exploit the application potential of coal pitch, this work proposes an oxidative modification co‐polymerization method. Using washing oil solubles (WOS) of low‐rank coal rapid pyrolysis tar residue and refined soft pitch (RP) as raw materials, high softening point isotropic coating pitch (HCP) was successfully prepared. The results indicated that HCP can effectively modify the surface defects of spherical graphite (SG) after coating. The derived amorphous carbon layer significantly enhances Li + diffusion kinetics and protects the internal graphite structure. When the coating amount was 10%, the obtained composite material (SG@C‐10%) exhibited electrochemical performance far exceeding expectations. Its initial coulombic efficiency (ICE) reached 95.25%, the reversible capacity at 5 C was 170 mAh·g −1 , and the capacity retention after 3000 cycles was 77.38%. Furthermore, when assembled into LiFePO 4 //SG@C‐10% full cell, the capacity retention after 1000 cycles at 5 C was 55.92%. This modification strategy achieves electrochemical performance comparable to more complex strategies in a cost‐effective manner, demonstrating promising application prospects and research value.