夹心结构ZnO-NiO-ZnCo_2O_4混合微米球锂的存储性能

Study of Lithium Storage Properties for Yolk-shell ZnO-NiO-ZnCo_2O_4 Composite Microspheres

通过简单的液相吸附法合成夹心结构的柠檬酸锌镍钴微米球并以此为自模板在空气中煅烧制备了夹心结构的ZnO-NiO-ZnCo2O4混合微米球.通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等研究方法对合成样品的物相、形貌、结构及成分进行了表征.用作锂离子电池负极材料时,夹心结构的ZnO-NiO-ZnCo2O4混合微米球显示出良好的锂存储性能.在100mA/g电流密度下充放电循环140次后夹心结构混合微米球的比容量达到1 194mAh/g.混合微米球优越的锂存储性能与其独特的夹心结构、小的纳米组成单元以及不同成分间的协同效应密切相关.

Yolk-shell ZnO-NiO-ZnCo2O4 composite microspheres were successfully synthesized with calcination of yolk-shell zinc-nickel-cobalt citrate microspheres precursor in air. The precursor was pre-produced through a two-step consecutive aging process of zinc citrate solid microspheres in nickel nitrate and cobalt nitrate solution. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM） were applied to characterize the morphologies,structures and compositions of the as-obtained samples. When used as the anode materials for lithium ion batteries, the harvested yolk-shell ZnO-NiO-ZnCo2 04 com- posite microspheres exhibited good electrochemical properties. After 140 cycles,a high specific capacity of about 1 194 mAh/g could be reached at a current density of 100 mA/g. The special yolk-shell configuration, the synergetic effect between ZnO, NiO and ZnCo2O4 nanoparticles,and the nanometer-sized building blocks of composite microspheres were responsible for excellent lithium storage properties.