空心球NiO水热法制备及电化学性能

摘要

Nickel oxide (NiO) hol ow spheres were successful prepared through hydrothermal method assisted with citric acid (CA). Characterization was carried out by using X-ray diffraction (XRD), BET and scanning electron microscopy (SEM). It revealed that CA played a key role in process of forming hol ow sphere structures. Results show that this material is weakly crystal ized, inter connected nanflakes network structure and has an arrow mesoporous distribution at about 4 nm. Electrochemical properties of NiO hol ow spheres were examined by cyclic voltammetry, galvanostatic charge-discharge. The results show that NiO calcined at 300℃ has a higher specific capacitance approximately up to 457 F/g at current density of 5 mA/cm2.%以Ni(NO3)2·6 H2O和NaOH为原料，柠檬酸(CA)为模板利用水热法制备了前驱体，然后烧结制得了球形NiO材料，在生成空心球结构的过程中柠檬酸起到了重要的作用。CA与Ni(NO3)2的摩尔比为1∶3时得到的NiO，X射线衍射(XRD)分析及扫描电子显微镜(SEM)形貌观察表明该材料主要呈现弱结晶态结构，空心球体结构表面为纳米片交错成空间网络。BET测试表明该材料的比表面积为236 m2/g，孔径分布约4 nm，且疏松，具有良好的OH－离子传递特性。循环伏安和恒流充放电测试表明，该材料有高的电化学活性，在5 mA/cm2电流密度下，氧化物比电容达457 F/g。