层状纳米MnO_2的液相合成及其电容性能  

Liquid Phase Synthesis and Capacitance Properties of Layered Nano MnO_2

作　　者：杨玉娟[1] 桑林[1] 黄成德[1] 

机构地区：[1]天津大学化工学院,天津300072

出　　处：《应用化学》2008年第4期473-476,共4页Chinese Journal of Applied Chemistry

摘　　要：室温、KMnO4与MnSO4不同摩尔比条件下液相反应合成了一系列层状结构的δ-MnO2纳米材料，通过XRD、循环伏安以及恒流充放电等测试技术对所得材料的结构和电容特性进行了研究。结果表明，所合成的MnO2为无定型结构的水合含钾二氧化锰（KxMnO2·nH2O），粒径较小，比表面积较大。当n（KMnO4）：n（MnSO4）=4：1时，所得MnO2材料电容性能最佳。将其在0．5mol／L Na2SO4水溶液中，-0．2～1．0V（vs．SCE）电位范围内，以94mA／g恒电流充放电时，比容量达290．03F／g；当恒定电流为1880mA／g时，放电比容量为195．49F／g。用375mA/g的恒定电流进行充放电循环时，测得其首次放电比容量达227．84F／g，100次循环后比容量仍为200．12F／g．约为起始比容量的88％．Layered nano δ-MnO2 was synthesized by reaction of KMnO4 and MnSO4 in liquid phase at different molar ratios. The materials were amorphous hydrated manganese dioxide （KxMnO2· nH2O） with small particle size and large specific surface area. Cyclic voltammetry （CV） and chronopotentiometry studies indicated that the MnO2 material obtained at a molar ratio of 4 ： 1 exhibited excellent capacitive behavior in 0.5 mol/L Na2SO4 aqueous electrolyte between - 0. 2 and ＋ 1.0 V （vs. SCE） , with its specific capacitance of 290. 03 F/g and 195.49 F/g at a discharge current density of 94 mA/g and 1 880 mA/g. The cycling behavior was studied by chronopotentiometry technique. At a current density of 375 mA/g, the first cycle showed the highest discharge specific capacitance of 227.84 F/g, and after 100 cycles it still was 200. 12 F/g, about 88% of its initial capacitance.

关 键 词：液相合成 超级电容器 Δ-MNO2 电容特性 

分 类 号：O646[理学—物理化学]