Ni(OH)_2/石墨烯/Co(OH)_2电极材料制备及其电容性能研究

Preparation of Ni(OH)_2/graphene/Co(OH)_2 electrode material and study on its capacitance performance

将具有法拉第赝电容但导电性较差的材料与具有良好导电性的石墨烯结合是提高超级电容器电极材料电容性能的合理策略。以水热法制备的Ni(OH)_2/石墨烯复合材料与生长有Co(OH)_2的泡沫镍制得修饰电极。用循环伏安法(CV)、恒电流充放电(CP)和电化学阻抗(EIS)测试了其在6 mol/L KOH溶液中的电容行为。实验表明,片状六边形Ni(OH)_2插入薄膜状石墨烯片层间,Ni(OH)_2/石墨烯/Co(OH)_2电极材料有良好的电容性能,在电流密度为1 A/g时比电容量达到了294 F/g,能量密度为36.75 Wh/kg。充放电循环1 000圈后比电容值仍是初始电容的92.7%。

It is a promising approach to enhance the specific capacitance of super capacitor electrode materials by combining high conductive carbonaceous materials（ such as graphene） with pseudo-capacitance materials of poor electronic conductivity.A modified electrode is prepared by the composition between Ni（OH）_2/graphene made via a hydrothermal process and nickel foam growing with Co（OH）_2.The morphology,composition and structure of as-prepared products are characterized by energy dispersive spectrometer（ EDS）,X-ray diffraction（ XRD） and scanning electron microscopy（ SEM）.The electro-capacitance performance of the composite in a 6 mol·L^（-1） potassium hydroxide solution is evaluated by cyclic voltammetry（ CV）,galvanostatic charge-discharge tests（ CP） and electrochemical impedance spectroscopy tests（ EIS）. The results show that the Ni（OH）_2/graphene/Co（OH）_2composite has higher specific capacitance of 294 F·g^（-1）with an energy density of 36. 75 Wh·kg^（-1） at current density of 1 A·g^（-1）.The modified electrode maintains 92. 7% of its initial specific capacitance after 1 000 cycles.