纳米Fe3O4- 活性炭混合超级电容器电化学性能的研究

研究了以纳米Fe₃O₄和活性炭(AC)为电极材料的超级电容器. 以FeSO₄·7H₂O和氨水为原料, 采用微波法制备出平均粒径为36nm的Fe₃O₄纳米粒子. 组装了以6mol/L KOH溶液为电解液的Fe₃O₄/KOH/Fe₃O₄、AC/KOH/AC、Fe₃O₄/KOH/AC三种类型的模拟电容器. 用循环伏安、恒流充放电和交流阻抗法对电容器进行了电化学性能测试. 结果发现, 混合电容器的工作电压可达到1.2V. 电流密度为0.5mA/cm²时, 正/负极质量比为1.5的Fe₃O₄/KOH/AC电容器的能量密度达到9.25Wh/kg, 与AC/KOH/AC电容器相比, 能量密度提高了53.4%.

Electrochemical Properties of Hybrid Supercapacitor with Nanosized Fe3O4/activated Carbon as Electrodes

The supercapacitor using nano-structured Fe₃O₄ and activated carbon (AC) as electrode materials was developed. Fe₃O₄ magnetic nanoparticles with average particle size of 36nm were synthesized by microwave method using FeSO₄·7H₂O and ammonia as the precipitator. Three kinds of supercapacitors, Fe₃O₄/KOH/Fe₃O₄, AC/KOH/AC, Fe₃O₄/KOH/AC, were prepared using 6mol/L KOH as electrolyte. Cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy were used to study the performance of the electrodes and the supercapacitors. The results show that the operating voltage of Fe₃O₄/KOH/AC hybrid supercapacitor is 1.2V. When the current density is 0.2mA/cm² and the weight ratio of active materials (Fe₃O₄/AC) is 1.5, the energy density of hybrid supercapacitor is 9.25Wh/kg, which is 53.4% higher than that of AC/KOH/AC capacitor with the same electrolyte.