Li二次電池正極活物質LiMn₂O₄の物性，電極特性における超音波処理の影響

抄録

In order to improve cathode property of LiMn₂O₄, we performed supersonic-wave treatments on LiMn₂O₄ powder in a Zn-containing aqueous solution and then heat-treated the obtained powder. Investigations on the samples clarified that the lattice constant of LiMn₂O₄ decreased and the Mn valence increased by the treatments, indicating a partial substitution of Zn for Mn. From charge-discharge cycle tests, it was demonstrated that the cycle performance of LiMn₂O₄ was drastically improved by the treatments although the first discharge capacity was deteriorated. We also carried out the investigations on the cathodes and electrolytes after the cycle tests, and found that the crystal structure of LiMn₂O₄ was stabilized by the treatments. From these results, it could be concluded that the partial substitution of Zn for Mn and/or a surface modification induced by the supersonic-wave treatments stabilized the crystal structure of LiMn₂O₄ and thus resulted in the better cycle performance.