MgCo_(2)O_(4)@Ni(OH)_(2)纳米针的制备及其超电性能研究

Preparation and supercapacitive properties of MgCo_(2)O_(4)@Ni(OH)_(2) nanoneedles

采用水热和电沉积方法成功合成出超级电容器MgCo_(2)O_(4)@Ni(OH)_(2)(MCON)电极材料。在导电基底泡沫镍上,絮状的Ni(OH)_(2)包覆着针状的MgCo_(2)O_(4),改善了母体材料的结构,构成了有效的电连接,从而增强导电性能。电化学性能测试表明,该MCON表现出优秀的电化学性能,其在1 mA/cm^(2)的电流密度下,比电容高达2635.4 F/g,容量提高了72.4%,且以14 mA/cm^(2)循环1000周次后比电容保持原有容量的91.2%。将MCON与活性炭分别以正极和负极组装成非对称超级电容器,其在电流密度1 A/g下,比电容达91.8 F/g。另外,该非对称超级电容器在功率密度为2.1 kW/kg下,能量密度为28.7 Wh/kg,同时点亮红色发光二极管时长高达25 min。研究结果表明设计复合材料拥有较强的储能能力,适合作为超级电容器电极材料。

MgCo_(2)O_(4)@Ni(OH)_(2)(MCON) electrode material for supercapacitors was succeessfully prepared by hydrothermal and electrodeposition in this work.Nanoneedle MgCo_(2)O_(4) was coated with cotton-shaped Ni(OH)_(2) on the conductive substrate of foam nickel,improving the structure of main material and constituting an effective electrical connection,thus enhancing the electrical conductivity.Electrochemical performance tests showed that this MCON exhibited excellent electrochemical properties,and it revealed a high specific capacitance of 2635.4 F/g at a current of 1 mA/cm^(2),indicating its canapcitance was increased by 72.4%.After 1000 cycles under the condition of 14 mA/cm^(2),91.2%of initial capacitance was retained.Asymmetric supercapacitor was assembled with MCON as binder-free positive electrode and activated carbon as negative electrode respectively,which displayed a specific capacitance of 91.8 F/g at 1 A/g.Besides,asymmetric supercapacitor showed energy density of 28.7 Wh/kg under the power density of 2.1 kW/kg.Meantime,a red light-mitting diode could remain lit for 25 min.The above results show that designing composite has a strong ability to energy storage,suitable as a supercapacitor electrode material.