超级电容器纳米氧化锰电极材料的合成与表征

Synthesis and Characterization of Nanostructured MnO_2 for Supercapacitor

以聚乙二醇为分散剂 ,利用高锰酸钾和醋酸锰溶液之间的化学共沉淀法制备纳米水合氧化锰 .借助SEM ,TEM ,FT IR ,XRD和BET分析手段对样品结构及性能进行表征 .研究结果表明 ,SEM和TEM显示所得粉体为纳米粉体 ,粒径大约为10～ 3 0nm左右 ,XRD分析表明该粉体为无定型α MnO2 ·nH2 O ,FT IR分析表明获得的粉体为水合物 ,BET测试比表面积达160 7m2 /g .以氧化锰为研究电极 ,饱和甘汞电极 (SCE)为参比电极 ,铂片为辅助电极的三电极体系中 ,以 1mol/L的Na2 SO4溶液为电解液 ,通过循环伏安法研究其电化学行为 .实验结果表明 ,纳米氧化锰是理想的超级电容器电极材料 ,在电位窗口为 -0 2～ 0 9V (vs .SCE)范围内 ,扫描速度为 4mV/s ,其比电容达到 2 0 3 4F/g .

Amorphous hydrous nanostructured MnO2 was synthesized in chemical coprecipitation method by mixing KMnO4 and manganese acetate aqueous solution using polyethylene glycol ( PEG) as disperser. The product was characterized by SEM, TEM, FT-IR, XRD and BET. The results show that the amorphous hydrous nanoparticles with the mean particle size of 10 similar to 30 nm were obtained and BET specific surface areas are 160.7 m(2)/g. Electrochemical characterization was carried out by cyclic voltammetry (CV). Amorphous alpha-MnO2.nH(2)O in 1 mol/L Na2SO4 aqueous electrolyte was proved to be an excellent electrode material for supercapacitor. The specific capacitance of 203.4 F/g was obtained at the scan rate of 4 mV/s in the range of -0.2 similar to 0.9 V (vs. SCE).