无机盐水溶液反应合成MnO_2纳米粉体及其电容特性

INORGANIC SALT WATER SOLUTION REACTION SYNTHESIS AND CAPACITOR CHARACTERISTICS OF NANO-MnO_(2) POWDER

采用无机盐水溶液反应合成了纳米MnO2粉末。X射线衍射结果表明:所制备的MnO2是αMnO2与γMnO2的混合晶相。透射电 镜分析表明:所制备的MnO2粒径为4～20nm。由所制备的粉末在300℃煅烧3h后作为活性物质制成电极。在1mol/L的(NH4)2SO4电解 液中,在电位范围(以饱和甘汞电极为参比电极)为0.15～0.75V的三电极体系中,通过循环伏安曲线考察了电极的电容性能。循环伏安结果 表明:所制备的纳米MnO2具有优异的电容性能,通过恒流充放电测得其比容量最高可达150.4F/g,循环2～3次后,充放电曲线进入稳定状 态,说明纳米MnO2具有较好的循环充放电性能。作为电极材料,纳米MnO2具有较好的应用前景。

Nano-MnO2 powder was synthesized by inorganic salt water solution reaction of KMnO4 and MnSO4. Results of X-ray diffraction and transmission electron microscope show that the phase of nano MnO2 powder prepared is the mixture of a-MnO2 and γ-MnO2 and its particle size is 4-20 nm. After calcined at 300°C for 3 h, the powder was used as active material to fabricate electrodes. The cyclic voltammograms of electrode prepared by the nano-MnO2 powder show good capacitive performance between 0.15 V and 0.75 V for saturated calomel electrode as reference electrode in 1 mol/L (NH4)2SO4. The maximum capacitance can reach to 150.4 F/g by calculating from the constant current charge/discharge curves. Discharge/charge curves are stabilized after two or three cycles, and the results demonstrate that MnO2 nano-powder has an ideal capacitance property and applications prospect as an electrode material.