【摘要】 通过KMnO4 和MnCl2 的低温固相反应 ,制备了掺杂稀土氧化镧的二氧化锰超大容量电容器复合正极材料。X射线衍射 (XRD)分析表明 ,所制备复合电极材料中的MnO2 是其α与γ相的混合晶相。透射电镜分析 (TEM )表明 ,复合材料呈棒状结构 ,其平均长度为 2 5 0～ 3 5 0nm ,平均直径为 15～ 2 0nm ,长径比大于 15。通过对新型复合电极材料进行电化学性能测试表明 ,掺入氧化镧的复合电极材料具有更好的充放电性能和电容特性 ,当MnO2 与La2 O3的质量比为 1∶0 .1时 ,复合电极在 2mol·L- 1 (NH4 ) 2 SO4 溶液中单电极最大放电比容量可达 15 6.15F·g- 1 ,比纯二氧化锰电极提高了 5 4.6% ,充放电效率提高了 19.5 %。更多还原

【Abstract】 Lanthanum oxide-doped MnO₂ composite electrode material was synthesized by low temperature solid state reaction between KMnO₄ and MnCl₂. During the process, polyethylene glycol （PG） was added as the dispersant, the mixed compounds was thoroughly ground and then put in water at 60 ℃ for several hours, finally the rod-shaped composite material is obtained. From XRD patterns, the sample is polycryctalline with the mixture of α- and γ-MnO₂. From TEM results, it could be seen that the sample has a length of 250～350 nm and a diameter of 15～20 nm. The ratio of length to diameter could reach more than 15. The electrochemical properties of the new materials were measured in the three electrode system. The cyclic voltammetric and constant current charge/discharge methods were used to explain the electrochemical properties. It could be seen that the composite materials show better properties than the pure MnO₂. When the weight ratio of MnO₂ to La₂O₃ is （1∶0.1）, the composite material has the best properties at relatively low current. In the 2 mol·L^-1 （NH₄）₂SO₄ solution, the maximum discharge special capacity was 156.15 (F·g^-1) and the charge/discharge efficiency could increase 19.5%.更多还原