γ—MnO_2电极在不同溶液中的可充性

The Rechargeability of γ-MnO_2 Electrode in KOH,NH_4C1+ ZnCl_2 and ZnSO_4 Solutions

用循环伏安法测量了γ—MnO_2电极在9mol/dm^3KOH、5mol/dm^3NH_4Cl+2mol/dm^3ZnCl_2和2mol/dm^3ZnSO_4三种溶液中的循环伏安行为;通过测量充放电电量定量地分析了γ—MnO_2在三种溶液中的可充电性;用X射线分析结果比较了三种溶液中可充电性的差异。实验结果表明,γ-MnO_2电解在NH_4Cl+ZnCl_2溶液中的可充电性最差,KOH溶液中次之,这两种溶液中,电极经过五次充放电循环后,γ—MnO_2的二电子放电效率降低了70％;ZnSO_4溶液中,γ—MnO_2电极显示出良好的可充电性,经100次充放电循环后,其二电子放电效率只降低9％,但其二电子放电效率较低,只有KOH溶液中的或NH_4Cl+ZnCl_2溶液中的一半。

Cyclic voltammetric curves of γ-MnO2 electrode in 9M KOH,5M NH4C1+2M ZnCl2 and 2M ZnSO4 solutions were determined. The rechargeability of γ-MnO2 electrode in these solutions was discussed. γ-MnO2 electrode has a good rechargeabili-ty in 2M ZnSO4 solution in which two electron discharge efficiency of the electrode was decreased by 9 percent of that at the first cycle after 100 cycles but the efficiency at the first cycle was only 35%. In 9M KOH or 5M NH4C1+2M ZnCl2 solution the efficiency of γ-MnO2 electrode was high (over 70%) but the rechargeability is poor,especially in 5M NH4Cl f55 2M ZnCl2 solution,and the efficiency was greatly decreased by over 70 percent of that at the first cycle only after 5 cycles.