二硫化镍/氢氧化镍空心球的制备及其电容器性能研究

以均匀硫纳米球为硬模板，通过直接沉淀法在硫纳米球表面包覆一层氢氧化镍纳米片，得到均匀硫@氢氧化镍前驱体，前驱体经低温煅烧获得二硫化镍/氢氧化镍复合纳米空心球，用其制备的电极具有良好的电化学性能。通过X射线衍射和透射电镜等对复合材料的成分和形貌进行分析。结果表明：复合材料纯度较高，组分为二硫化镍和氢氧化镍，二者物质的量比约为1∶1；复合材料是大小均匀的多孔纳米空心球，空腔直径约为500 nm，表面覆盖超薄纳米片，长度约为250 nm，整体形如花球，大小约为1 μm。采用循环伏安、计时电位等方法对复合材料超级电容器性能进行研究。结果表明，在1 A/g电流密度下电极比电容达到1 446 F/g；在20 A/g电流密度下电极比电容仍高达976 F/g；在10 A/g电流密度下循环5 000次，电极容量保持率为86.4%，具有良好的倍率性能和循环稳定性。

Study on preparation of NiS2/Ni（OH）2 hollow spheres and its capacitor performance

The homogeneous S@Ni（OH）2 precursor composite was synthesized via direct precipitation method which was based on uniform sulphur nanospheres as hard template coated Ni（OH）2 nanosheets.The NiS2/Ni（OH）2 nanospheres with a lot of mesoporous was obtained by low temperature calcination of the precursor which showed outstanding electrochemical properties.The contents and morphology of products were characterized by X-ray diffraction and transmission scanning electron microscopy.The results showed that the composite had high purity which was constituted by NiS2 and Ni（OH）2，and the amount of substance ratio of NiS2 to Ni（OH）2 was about 1:1.The composite was uniform sunflower like porous hollow nano spheres which the size was approximately 1 μm，the cavity was approximately 500 nm in diameter，covered by ultra thin nanosheet with a length of approximately 250 nm.Its electrochemical performance was tested by cyclic voltammetry and galvanostatic chargedischarge method etc..Results showed that the specific capacitance of NiS2/Ni（OH）2 nanospheres elec trode could reach 1 446 F/g at 1 A/g，even retained 976 A/g at 20 A/g．And the specific capacitance retention at a current density of 10 A/g for NiS2/Ni（OH）2 nanospheres could retain 86.4% of the initial capacitance after 5 000 cycles，showed high rate capability and cycling stability.