Abstract: Due to the difference of energy storage mechanisms between the anode and cathode materials, the power density or rate performance of a lithium-ion capacitor is greatly limited by its anode material. Hard carbon is a promising anode material for lithium ion capacitors, and its modification is an important way to improve the electrochemical performance of lithium-ion capacitors. A commercial hard carbon from Kuraray Inc was modified by oxidation followed by intercalation with ZnCl₂ (ZnCl₂―OHC). The reversible capacity of a half-cell prepared using this material was 257.4 mAh·g⁻¹ at 0.05 A·g⁻¹, which is obviously higher than the unmodified one (172.5 mAh·g⁻¹). The capacity retention of a full cell prepared using ZnCl₂―OHC as the anode and activated carbon as the cathode reached 43.3% when the current density increased from 0.1 to 10 A·g⁻¹, which is more than twice that of the untreated hard carbon. After 5 000 charge-discharge cycles at 1 A·g⁻¹, the capacity retention of the full cell was about 98.4%. The modification of hard carbon by surface oxidation and intercalation is therefore a promising way to improve its anode performance for lithium ion capacitors.