Huichao Dong

Electrochemical properties of Bi-Ni and Bi-Ni-Mn composite-coated electrolytic manganese dioxide

The Bi-Ni and Bi-Ni-Mn composite is separately coated on the surface of commercial electrolytic manganese dioxide (EMD) by using a simple chemical precipitation/oxidation method. The results of X-ray diffraction show that a structure of γ-MnO2 is kept for all the coated EMD, but the intensity of their diffraction peaks is lower than uncoated one. Both the Bi0.5-Ni0.5 and Bi0.35-Ni0.35-Mn0.3 composite benefits the discharge capacity and high-power performance of the EMD electrodes. On the other hand, the results of scanning electron microscopy and energy dispersive spectroscopy confirm the more uniform distribution of the Bi0.15-Ni0.55-Mn0.3 composite on the surface of EMD than the Bi0.5-Ni0.5 one, thereby resulting in better cyclability of the electrodes. After 50 cycles at a 1C rate, the capacity retention rate of the Bi0.15-Ni0.55-Mn0.3 composite-coated electrode reaches to 80%, which is far larger than the un-coated (49%) and the Bi0.5-Ni0.5 composite-coated (63%) one.