乙醇-水体系电沉积制备Ni(OH)_2超级电容器正极材料的研究

Study on Ni(OH)_2 supercapacitor positive electrode material prepared by electrochemical deposition in the ethanol and water system

采用电化学共沉积技术在泡沫镍基体上制备了掺杂Co的Ni(OH)2电极,研究了乙醇与水体积比为3∶7,1∶1和7∶3及水溶液情况下,C/Ni(OH)2超级电容器的容量特性。XRD分析表明,所得产物为掺杂Co的-αNi(OH)2;电池测试表明在乙醇与水体积比为1∶1时,能获得最好的电化学充放电特性,在小电流4mA/cm2充放电下,比容量达850F/g;在大电流32mA/cm2充放电下,比容量可达600F/g,其比容量数值随循环次数增加逐渐趋于稳定。扫描电镜观察表明,乙醇与水体积比为1∶1时所得电沉积Ni(OH)2呈细小的蜂窝状三维结构,增大了活性物质与电解液接触的比表面积,使电化学反应更加充分,提高了活性物质的利用率和放电比容量。

Ni(OH)_2 electrode doping with Co was prepared on porous nickel by electrochemical co-deposition technology.Capacitance performance of C/Ni(OH)_2 supercapacitor was studied in the ethanol and water with volume ratios 3∶7,1∶1,7∶3,respectively and water solution.XRD and EDS analysis indicates that the product is α-Ni(OH)_2 doping with Co.Charge-discharge tests show that the supercapacitor can acquire the best characteristics in the ethanol and water with volume ratio 1∶1,and the single electrode specific capacitances can reach 850 F/g and 600 F/g at 4mA/cm^2 and 32 mA/cm^2,respectively.SEM images show that such Ni(OH)_2 particles exhibit a honeycombed structure,which increases specific surface area contacted between the active material and electrolyte and makes electrochemical reactions more fully,so that the utilization ratio and the value of discharge specific capacitance of the active material are increased greatly.