载镍活性炭材料及复合型超级电容器

Activated carbon capacitor materials loaded with nickel oxide and the hybrid capacitor

摘要:

为提高碳基电化学电容器的比电容和和能量密度,采用化学沉积法将少量镍氧化物沉积在活性炭上,得到沉积镍氧化物的活性炭材料并以此材料做成复合电极用于混合型电化学电容器的正极.研究显示,沉积镍氧化物后,碳材料的比表面积略有减小,但孔径分布没有明显变化.复合电极作为混合型电容器的正极时,比电容达到194.01F/g,比纯活性炭正极的175F/g提高了10.84%;复合电极在6mol/L的电解液中析氧电势为0.296V,比纯活性炭电极的0.220V高出0.076V,因此,具有较高的能量密度.不同放电电流密度下的恒电流测试结果显示,沉积镍氧化物活性炭复合电极的比电容值没有明显变化,与纯活性炭电极一样表现出良好的功率特性.采用沉积镍氧化物活性炭作为正极材料的复合型电容器,在6mol/L的KOH水溶液作为电解液时,单体电容器的工作电压可以达到1.2V,高于纯活性炭制备的双层型电容器0.2V.充放电循环10000次时,复合型电容器的电容仅降低到初始电容的90%.上述结果表明,在活性炭上沉积少量镍氧化物颗粒可以提高碳基电化学电容器的比电容和能量密度.

Abstract:

In order to enhance the specific capacitance and energy density of carbon-based supercapacitor,some particles of nickel oxide were loaded into activated carbon.A hybrid type electrochemical capacitor was made and tested,in which the activated-carbon loaded with nickel oxide was used as anode material and activated-carbon was used as cathode material.Results show that the BET surface area of the activated-carbon decreases due to the deposition of nickel oxide,but no obvious change is found in the pore size distribution.The specific capacitance of the capacitor is increased from 175.40 F/g to 194.01 F/g.The potential of oxygen evolution on the composite material electrode reaches 0.296 V,and it is 0.076 V higher than that on the pure activated-carbon electrode,which indicates that the hybrid capacitor has high energy density.Similar to the pure activated-carbon electrode,no obvious change appears on the specific capacitances of the composite material electrode at various discharge currents and the composite material electrode exhibits good power characteristics.The operation voltage of the hybrid capacitor is 1.2 V in the electrolyte of 6 mol/L KOH solution,which is 0.2 V higher than that of double-layer capacitor made of activated carbon.It is concluded that the specific capacitance and energy density of carbon-based supercapacitor can be enhanced by loading some nanometer-scale particles of nickel oxide into activated carbon.