掺Cr改性MnO_2的制备及其电化学性能

Preparation and electrochemical performance of Cr doped MnO_2

采用低温固相氧化还原反应法制备出掺Cr的纳米MnO2。通过X射线衍射仪对其结构进行表征, 结果表明: 所得样品为α MnO2 和γ MnO2 的混合晶相, 以纳米MnO2 作为超级电容器的电极材料的单电极活性物质测得其比电容为 95F/g, 掺入Cr的电极材料其比电容最大可达到 163F/g。循环伏安和恒流充放电测试结果表明,化学掺杂的配比对MnO2 电化学性能的影响较大。当Mn与Cr的摩尔比为 100∶1时, 材料具有较好的放电性能,其放电容量可提高 70%。表明化学掺杂Cr有利于提高MnO2 电极的电化学性能。

Chromium doped Nano-MnO_2 were synthesized by low temperature solid-state reaction. The charactrization and performance of samples were studied by X-ray diffraction. The results show that the product is the mixture of α-MnO_2 and γ-MnO_2, the specific capacitances of pure MnO_2 and chromium doped MnO_2 are 95F/g and 163F/g. The results of the cyclic voltammograms and the constant current charge/discharge curves show that the ratio of chromium in samples has greater effect on the electrochemical capacity, the better discharge capacity can be obtained when the mole ratio of Mn to Cr is 100 and the discharge capacity of MnO_2 electrodes is 70% higher.