金属有机骨架衍生NiCo_(2)O_(4)/rGO复合材料的制备及其超级电容性能

Preparation and Supercapacitive Performance of Metal-Organic Framework Derived NiCo_(2)O_(4)/rGO Composites

采用溶剂热法,按照镍和钴金属盐与氧化石墨稀(GO)质量比分别为1:0.05,1:0.07,1:0.09的配比制备镍钴金属有机骨架(Ni-Co-MOF)/GO前驱体,并将其超声喷涂在加热的泡沫镍基底上制备NiCo_(2)O_(4)/rGO(还原氧化石墨烯)复合电极材料,研究了该复合材料的微观结构和电化学性能。结果表明:NiCo_(2)O_(4)/rGO复合材料由褶皱石墨烯及其表面均匀分布的NiCo_(2)O_(4)纳米颗粒构成;在2 A·g^(-1)电流密度下,盐与GO质量比为1:0.07时复合材料的比电容高达991 F·g^(-1),在20 A·g^(-1)电流密度下充放电30000次后,初始电容保持率仍高达126%。组装而成的NiCo_(2)O_(4)/rGO//AC非对称超级电容器的能量密度可达到41 W·h·kg^(-1),对应的功率密度为1604 W·kg^(-1),在20 A·g^(-1)的电流密度下经过25000次充电/放电循环后仍可实现100%以上的电容保持率,表现出超长的循环寿命。

Nickel-cobalt metal-organic framework(Ni-Co-MOF)/graphene oxide(GO)precursors were prepared by solvothermal synthesis with mass ratios of nickel and cobalt metal salts to GO of 1:0.05,1:0.07,and 1:0.09,respectively,and then were ultrasonically sprayed on the heated nickel foam substrate to obtain NiCo_(2)O_(4)/reduced graphene oxide(rGO)composite electrode materials.The microstructure and electrochemical properties of the composites were studied.The results show that the NiCo_(2)O_(4)/rGO composite was composed of wrinkled graphene and NiCo_(2)O_(4) nanoparticles uniformly distributed on graphene surface.When the mass ratio of salt to GO was 1:0.07,the composite had a high specific capacitance of 991 F·g^(-1) at a current density of 2 A·g^(-1);after 30000 cycles of charge and discharge at a current density of 20 A·g^(-1),the initial capacitance retention was still as high as 126%.The assembled NiCo_(2)O_(4)/rGO//AC asymmetric supercapacitor had an energy density of 41 W·h·kg^(-1) at a power density of 1604 W·kg^(-1),and achieved capacitance retention greater than 100%after 25000 charge/discharge cycles,showing an ultra-long cycle life.