Studies On Rechargeable Lithium Manganese Dioxide Coin Cells

As cathode materials, manganese dioxide had been used in primary batteries widely. In order to satisfy the need of new electrical appliances, more and more researchers interest in the studies of rechargeable lithium manganese coin cells, which have wide working temperature, super electrochemical characteristics and low price. And the main research fields of rechargeable lithium coin cells are development of new cathode materials and optimization of electrolyte. Therefore, in this paper, cathode materials for rechargeable lithium coin cell were prepared, and electrolyte was optimized, and then rechargeable 2016 lithium coin cells were developed.Lithiated manganese dioxide-LixMnO₂ used as cathode materials in rechargeable lithium coin cells was synthesized using a melt-impregnation method. Physics and chemical properties of LixMnO₂ were analyzed, and electrochemical characteristics of which were evaluated. Thus the ratio of Li/Mn, i.e. 0.30:1, was optimized. The results show that rechargeable lithium coin cells with Li_0.30MnO₂ as cathode materials have high capacity and good reversibility. On the base of the ratio confirmed, the effects of heating factors on material performance were discussed. And then, the optimized heating temperature-350℃and heating time-15h were confirmed.Electrolytes for rechargeable lithium cells were made by LiClO₄, which was solute, and several solvents and additives. The concentration of LiClO₄-1M was confirmed by the examination of conductivity. The electrochemical stability of electrolytes was discussed by different substrates. Finally, the cycle efficiency of Li-Al alloy with different electrolytes was studied. Therefore, the electrolyte with LiClO4/DOL/TEA system has high conductivity, good stability, and high cycle efficiency.On the base of former work, 2016 rechargeable lithium coin cells with Li_0.30MnO₂ as cathode materials, Al-Li alloy as anode materials, and LiClO₄/DOL/TEA system as electrolyte were made. And the discharge characteristics, temperature properties, cycle times, storage performance and cyclic voltammograms were examined. Electrochemical reactions under different potentials were analyzed by EIS. Finally, the relevant equivalent circuit was designed, and then electrochemical parameters were simulated. In a word, the rechargeable lithium manganese coin cells with synthesized cathode materials and optimized electrolytes have high discharge capacity, good reversibility, which possessed super electrochemical performance.