The Electrochemical Characterization of $LiMn_{2-y}M_{y}O_{4}$ Cathode Material. III. The Effect of Temperature on the Charge-discharge Property and AC Impedance of $LiMn_{2-y}M_{y}O_{4}$

$LiMn_{2-y}M_{y}O_{4}$ 정극 활물질의 전기화학적 특성. III. $LiMn_{2-y}M_{y}O_{4}$의 충방전 특성과 AC 임피던스의 온도 의존성

Spinel LiM $n_2$ $O_4$ and LiM $n_{1.9}$M $g_{0.1}$ $O_4$ power was synthesized with solid-state method by calcining the mixture of LiOH.$H_2O$, Mn $O_2$ and MgO at 80$0^{\circ}C$ for 36 h in an air atmosphere. To investigate the effect of temperature on he cycle performance of cathode material during cycling, charge-discharge experiments and ac impedance measurement were performed. Initial discharge capacity was gradually increased with the increase of charge-discharge temperature. Discharge capacity at high temperature was suddenly decreased during cycling. On the other hand, discharge capacity at low temperature was almost constant during cycling. It confirmed that Mn dissolution is serious at high temperature than at low temperature. LiM $n_2$ $O_4$ and LiM $n_{1.9}$M $g_{0.1}$ $O_4$ showed the best capacity and stability at room temperature.ure.ure.