Spinel-type lithium–manganese oxide cathodes for rechargeable lithium batteries

Dissolution of Mn ions and capacity loss of spinel-type Li–Mn oxide cathodes in LiPF6-containing electrolytic solutions at 60°C were investigated. The amounts of dissolved Mn decreased with the increase in the Li/Mn molar ratios in Li–Mn oxides. The dissolution reaction of Mn ions was enhanced on charged cathodes, resulting in a cathode capacity loss and a contraction of the lattice parameter. An increase of the polarization voltage was considered to cause a capacity loss on the charged cathodes during the course of immersion at 60°C, as well as the dissolution of Mn ions.