Improvements in lithium secondary cells

Hermetic AA-size lithium secondary cells with spiral-wound electrode design were used to compare the performances of four commercially available active cathode materials. The four cathode materials tested were LiNiO₂, LiCoO₂, LiMn₂ O₄, and Li₂Mn₄O₉, supplied by Cyprus Foote Mineral Company. Under room temperature conditions, cells with Li₂Mn₄O₉ as active cathode material demonstrated long cycle life at 0.7 F/mol. However, for a short-term cycle at 70°C, significant changes in cathode utilization were observed with a loss in capacity for the two Li-Mn-O spinel materials and an increase in capacity for LiNiO₂ and LiCoO₂