Carbon Anodes Derived from Quinoline‐Soluble Pitch Fractions for Improving Sodium‐Ion Storage Performance

ABSTRACT

Pitch, with low cost and high carbon content, is regarded as an excellent precursor for anode materials of sodium‐ion batteries. The complicated molecular composition of pitch results in differences in the microscopic structure of the derived carbon, which in turn affects its sodium storage performance. In this paper, a quinoline‐soluble fraction carbon anode material (TQSC) was prepared using medium‐temperature coal pitch as the raw material and quinoline as the solvent through solvothermal dissolution and reaction, followed by centrifugation, solvent removal, and carbonization. The removal of the quinoline‐insoluble (QI) fraction reduced the heavy polycyclic aromatic hydrocarbon structure in the precursor and effectively inhibited graphitization during the carbonization process. This produced a structure where local short‐range graphite domains and a large number of disordered regions coexist, thereby improving the sodium storage performance of pitch‐based carbon materials. After 300 cycles, the specific capacity of TQSC remained approximately 243 mAh g ⁻¹ at 0.1 A g ⁻¹ . Meanwhile, it delivered a discharge specific capacity of 110 mAh g ⁻¹ at 5 A g ⁻¹ . This indicates that TQSC exhibited good cycle stability and rate performance.