ZnCo_2O_4纳米线的制备及其电容性能研究

Preparation of ZnCo_2O_4 Nanowires and Their Capacitive Properties

ZnCo_2O_4(ZCO)由于其良好的电化学活性而被备受关注。采用水热法和热退火两步法成功地在镍泡沫上制备了ZnCo_2O_4纳米线。利用扫描电镜(SEM)和X射线衍射谱(XRD)对ZnCo2O4的形貌和结构进行了表征。这种独特的一维结构可以为电子和离子提供有效的传输途径。在三电极系统下,通过循环伏安测试和恒电流充放电测试表明,在120℃水热条件下所制得的ZCO-120的电容性能最佳,在0.5 A/g的电流密度下,其比电容达到511.3 F/g。在10.0 A/g的电流密度下经1 000次循环充放电后,其比电容仍然保持95.8%,表明其具有较好的循环稳定性。同时,将ZCO-120作为正极,活性炭作为负极组装成不对称超级电容器,其电势窗可达到1.6 V,在功率密度为400 W/kg时,能量密度可达14.4 Wh/kg。证明了ZnCo_2O_4可以作为先进的超级电容器材料。

ZnCo2O4(ZCO)has attracted much attention due to its good electrochemical activity.We prepared ZnCo2O4 nanowires on nickel foam by two-step method hydrothermal method and subsequent thermal annealing successfully.The morphology and structure of ZnCo2O4 were characterized by scanning electron microscopy(SEM)and X-ray diffraction(XRD).This unique one-dimensional structure provides an efficient means of transport for electrons and ions.Under the three-electrode system,the cyclic voltammetry test and the galvanostatic charge-discharge test show that the ZCO-120 has the best capacitance performance under hydrothermal conditions of 120℃at 0.5 A/g current density and the capacitance reaches 511.3 F/g.After 1 000 cycles of charge and discharge at a current density of 10.0 A/g,the specific capacitance remained at 95.8%,indicating that it has good cycle stability.Then,ZCO-120 is used as the positive electrode and activated carbon is used as the negative electrode to assemble an asymmetric supercapacitor with a potential window of 1.6 V.At a power density of 400 W/kg,the energy density can reach 14.4 Wh/kg.It proves that ZnCo2O4 can be used as an advanced supercapacitor material.