纳米MnO_2的制备及电化学性能研究

Synthesis and characterization of nano-size manganese dioxide

采用溶胶凝胶法(sol gel)制备了纳米MnO2,并对其进行了酸化和高温处理。采用化学分析、XRD、红外光谱、循环伏安、恒流放电等测试方法对处理前后的样品进行分析。研究结果表明,酸化后的样品氧化度和表面积增大,粒径减小,放电容量增大;经过500℃高温及酸化处理后的样品,其氧化度更高,粒径更小,其原因可能是高温酸化后,样品中的质子与O2-更易结合,从而使样品的活性提高。制备的纳米MnO2与电解二氧化锰(EMD)相比,在-0.4V处,其放电容量高出52%。

Nano-size MnO_2 power was prepared by sol-gel method, and it was acidified and thermal-acidified respectively. Samples were analyzed by chemical analysis, XRD, IR, constant current discharge and cyclic voltammetry. The results indicate that the acidification increases sample's oxidation, decreases particle's diameter, enlarges the surface area and the discharge capacity. The thermal-acidified treatment at 500 ℃ makes the oxidation of sample higher and particle diameter smaller. The proton of sample combines with O^(2-) more favorably, so it improves the activity and the discharge capability remarkably. Compared with EMD, the discharge capacity of the sample after thermal-acidified treatment is about 52% larger than that of EMD at -0.4 V.