关键词: 海胆状MgCo₂O₄, 比电容, 循环稳定性, 超级电容器

Abstract: MgCo₂O₄ theoretical specific capacitance is up to 3 122 F/g. Due to the influence of its morphology，structure，conductivity，and other factors，the actual specific capacitance value is not high. To obtain MgCo₂O₄ electrode materials with high specific capacitance，we prepared sea urchin-like MgCo₂O₄（M-10）on the nickel foam framework by hydrothermal method. Phase characterization analysis and electrochemical performance testing were performed by the X-ray diffraction，scanning electron microscopy，and electrochemical workstation. The results showed that the specific capacitance of M-10 was up to 1 090. 8 F/g when the current density was 1 A/g. As a binder-free supercapacitor electrode material， the specific capacitance of M-10 remained 91% when it circulated 5 000 cycles at 20 A/g current density，which had good cycle stability. In addition，we assembled M-10∥AC asymmetric supercapacitor （M-10∥AC ASC） with M-10 as the positive and activated carbon（AC）as the negative. The specific capacitance of M-10∥AC ASC was 69. 8 F/g when the voltage window was 0 ～ 1. 5 V and the current density was 1 A/g. Simultaneously， after 3 000 cycles，the specific capacitance retention ratio was 96. 8%，indicating that M-10 can be used as a good energy storage electrode material.

Key words: sea urchin-like MgCo₂O₄, specific capacitance, cycle stability, supercapacitor