Composite Lithium Ionization for Natural MnO2
Aimed at the problem of low purity and poor electrochemical activity of natural MnO2, acid-treatment was applied to pre-treat natural MnO2. Three factors, such as H2SO4 concentration, bathing temperature and reaction time, were accessed. The best acid treatment conditions of natural MnO2 were determined through an orthogonal experiment of 3 factors and 3 levels, using the initial discharge capacity at 0.2C rate as an index, that is, H2SO4 concentration 2mol•L-1, bathing temperature 30oC, reaction time 4h. Lithiated manganese dioxide-Li0.3MnO2 was prepared by melt-impregnation method using the MnO2 pre-treated under the optimal acid-treatment conditions, which showed an initial discharge capacity of 186.7 mAh•g-1 at 0.2C rate and little capacity degradation after 300 cycles at 20%DOD.
Jinsheng Liang and Lijuan Wang
Y. H. Cheng et al., "Composite Lithium Ionization for Natural MnO2", Advanced Materials Research, Vol. 96, pp. 29-33, 2010