多级结构NiO纳米材料的合成及电化学性能

Synthesis and properties of hierarchical NiO nano materials

以Ni(NO_3)_2·6H_2O为镍源,以尿素为沉淀剂,采用微波水热法合成了氢氧化镍纳米粉体,对其进行煅烧得到多级结构的NiO纳米粉体.采用XRD、SEM和TEM对煅烧前后产物的物相和微观形貌进行研究;并用BET对煅烧后样品的孔径分布及孔隙率进行测试.结果表明:NiO纳米粉体保留了氢氧化镍前驱体纳米片自组装形成的多级孔结构.煅烧后比表面积由41.31cm^2·g^(-1)增加到166.69cm^2·g^(-1).多级结构NiO的孔径分布在2~40nm,孔体积达到了0.36cm^3·g^(-1).NiO作为锂离子电池负极材料在100mA·g^(-1),100次循环后容量基本保持在800mAh·g^(-1),NiO纳米材料电化学性能测试表明其充放电循环性能稳定而高效.

NiO nanopowders with hierarchical structure were obtained by the heat treatment of the nickel hydroxide nanopowders, which were prepared by microwave hydrothermal, u-sing NKNO3 ）2 · 6H2O and ureas as raw materials. The phase and microstructure of the sam-ples were studied by XRD, SEM and TEM. The pore size distribution and porosity of the samples after heat treatment were tested by BET nitrogen adsorption isotherm measure-ment. Results showed that the NiO nanopowders retained the similar morphology with the nickel hydroxide precursor, which present hierarchical porous structure assembled nanoshe-ets. The specific surface area of the samples increased from 41. 31 cm^2· g^-1 to 166. 69 cm^2 · g^-1after calcination. The pore size of NiO nanopowders distributed in 2-40 mm,and the pore volume reached the 0. 36 cm 3· g^-1 . The reversible capacity is about 800 mAh · g^-1 under a current density of 100 mA · g^-1 with 100 cycles. It is indicated that NiO nanopowders has high rate capacity and good cyclic reversibility.