不同形貌氧化镍纳米材料的合成及其电化学性能

以水-乙二醇为溶剂,以聚乙烯吡咯烷酮(PVP)为表面活性剂,采用溶剂热法合成了NiO纳米片,NiO纳米薄片通过自组装形成花状结构。改变反应温度和溶剂,制备了NiO纳米立方体颗粒和NiO纳米球形颗粒。用合成的NiO纳米材料制备工作电极,在6 mol/L的KOH溶液中利用三电极体系进行了电化学性能测试。在电化学性能测试中进行了循环伏安测试、恒电流充放电测试和电化学阻抗谱(EIS)测试。结果表明,NiO纳米片的比电容最高(在电流密度为0. 5 A/g时比电容值为402 F/g),倍率性能最佳(0. 5 A/g增加至4 A/g时有80. 1%的电容保持率)。在电流密度为4 A/g时对NiO纳米片进行1000次恒流充放电循环测试,比电容损失了9. 7%。

Synthesis and Electrochemical Properties of NiO Nanomaterials with Different Morphologies

NiO nanosheets have been synthesized via a facile solvothermal route using water-ethylene glycol as solvent and polyvinyl pyrrolidone(PVP) as surfactant. These NiO nanosheets were interweaved with each other to form hierarchical flower-shaped structures. Nanocubes and nanospheres were also obtained through changing the reaction temperature and solvent. The electrochemical tests were conducted using a three-electrode system in 6 mol/L KOH with the as-synthesized NiO as the working electrode. Electrochemical properties were characterized by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. NiO nanosheets exhibit the highest specific capacitance(402 F/g at current density of 0.5 A/g) and the best rate capability(80.1% capacitance retention from 0.5 A/g to 4 A/g). NiO nanosheets also show excellent cycle stability, only lost 9.7% after 1000 cycles.