酸度控制的不同MnO2的水热制备及电化学性能

以KMnO4为锰源、CO(NH2)2为还原剂,通过水热反应制备MnO2,考察了体系酸度对产物结构和形貌的影响,应用X-射线衍射、扫描电镜和N2吸-脱附技术对产物进行表征。结果表明,在0~1mol/LH2SO4溶液中,制备了颗粒状、球形、纤维状和海胆状MnO2,前两种MnO2为层状结构,后两种MnO2具有隧道结构。海胆状MnO2的比表面积高达95m^2/g。电化学测试结果显示,在0.1A/g的电流密度下,海胆状MnO2首次放电比容量达到1318.8mAh/g。恒流充放电140次后,容量保持率为74%。

Hydrothermal Preparation of Different MnO2 Controlled by Acidity and Its Electrochemical Performance

MnO 2 were prepared by hydrothermal method using KMnO 4 as a manganese source and CO(NH 2) 2 as a reducing reagent. The effects of acidity on structure and morphology of products were investigated. The obtained products were characterized by X-ray diffraction, scanning electron microscopy and N 2 adsorption-desorption. Results show that MnO 2 with different morphologies of particles, spheres, fibres and urchins were successfully prepared in 0-1 mol/L H 2SO 4 solution. The former two kinds of MnO 2 are layered structure, while the latter two kinds of MnO 2 are tunnel structure. And MnO 2 urchins have high specific surface area (95 m^2/g). Electrochemical measurements indicate MnO 2 urchins exhibit an initial discharge capacity of 1318.8 mAh/g at the current density of 0.1 A/g. And the capacity retention reaches 74% after 140 cycles.