摘要
以KMnO_4为锰源、CO(NH2)2为还原剂,通过水热反应制备MnO_2,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0~1 mol/L H2SO4溶液中,制备了颗粒状、球形、纤维状和海胆状MnO_2,前两种MnO_2为层状结构,后两种MnO_2具有隧道结构。海胆状MnO_2的比表面积高达95 m2/g。电化学测试结果显示,在0. 1 A/g的电流密度下,海胆状MnO_2首次放电比容量达到1318. 8 m Ah/g。恒流充放电140次后,容量保持率为74%。
MnO_2 were prepared by hydrothermal method using KMnO_4 as a manganese source and CO( NH2)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 N2 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 m2/g). Electrochemical measurements indicate MnO_2 urchins exhibit an initial discharge capacity of 1318. 8 m Ah/g at the current density of 0. 1 A/g. And the capacity retention reaches 74% after 140 cycles.
引文
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