ZIF-67, NiC₂O₄·2H₂O and NiC₂O₄/ZIF-67 materials are synthesized by a hydrothermal method. The NiC₂O₄/ZIF-67 electrode delivers a maximum capacitance of 1019.7 F g⁻¹ at a scan rate of 5 mV s⁻¹, and can maintain the specific capacitance of 73% after 2000 cycles in the 6 M KOH electrolyte.