化学改性MnO_2纳米粉体的固相合成及性能

Synthesis of chemical modified MnO_2 nano-sized powder by solid-state reaction and their performance

通过固相反应制备了单掺Pb、单掺Bi化学修饰MnO2 以及掺Pb和Bi化学修饰MnO2 纳米粉体样品。X射线衍射、透射电镜测试结果表明。所得样品主要为 β MnO2 ,粒径在 3 0～ 5 0nm之间。循环伏安以及循环充放电测试结果表明Pb、Bi的掺入改变了MnO2 的充放电机理。在其循环充放电过程中 ,掺杂物与MnO2 形成了一系列MnyPbx(y =4+ ,3 + ,2 + ;x =0 ,2 + )以及MnyBiz(y =4+ ,3 + ,2 + ;z =0 ,3 + )复合物 ,其共氧化与共还原抑制了电化学惰性物质Mn3 O4的生成和积累 ,使得改性MnO2

The chemical modified MnO 2 nano sized powder samples doped with Pb and Bi separately and that doped with both Pb and Bi were synthesized by means of solid state reaction. The test results of X ray diffraction (XRD) and transmission electron mirror (TEM) show that the most synthesized samples are β MnO 2 with the grain size of 30-50 nm. The test results of cyclic voltammetry and charge/discharge cycles show that the charge/discharge mechanism of MnO 2 is changed by the doping of Pb and Bi. The production and accumulation of electrochemical inert material Mn 3O 4 is inhibited by the co oxidation and co reduction of Mn yPb x(y=4+, 3+, 2+;x=0,2+) and Mn yBi z(y=4+,3+,2+;z=0,3+) complexes, which are formed by the reactions between doped materials and MnO 2 during charge/discharge cycles. Therefore, the discharge capacity and cycle life of modified MnO 2 is improved.