LiM_xMn_(2-x)O_4(M=Cr、Al)尖晶石相阴极材料研究

用溶胶 -凝胶法制备了 L i Mx Mn2 - x O4( M=Cr、Al;x≤ 0 .2 )尖晶石相锂离子电池阴极材料。SEM表面观测显示材料的晶形好 ,粒度均匀 ,粒径小于 0 .5微米。电化学测试表明 ,低水平量 ( 0 .0 2≤ x≤ 0 .0 5 )的 Cr、Al掺杂材料初始容量稍有降低 ,但却较大地改善了循环性能。在 L i Mx Mn2 - x O4中 ,掺 Al降低了 L i+、Mn3+占位的无序度 ;Cr3+和 Al3+取代了其中的部分 Mn3+ ,占据八面体位 ( 16 d) ,抑制了 Jahn-Teller效应 ,增强了尖晶石骨架的稳定性 ,提高了其电化学性能。在 3.0～ 4.3V的充放电过程中 ,材料中的 Cr、Al都保持 +3价不变 ,不发生氧化还原

The Spinel Phases LiM_xMn_(2-x) O_4(M=Cr、Al)as the Cathode for Rechargeable Iithium Batteries

In order to improve the cycle performance of LiMn 2O 4, the spinel phases LiM xMn 2-x O 4(M=CR?Al, x≤0.2)as the cathode for Li ion batteries are synthesized by a solgel method. SEM images indicate they have good crystallinity and uniform particle sizes (≤0.5μm). By substituting at the lower level of Cr and Al (0.02≤x≤0.05), the cycle performance is remarkably improved at the little loss of an initial capacity. In LiM xMn 2-x O 4 doping Al makes the disorder of Li + and Mn 3+ decreased. Both Cr 3+ and Al 3+ replace Mn 3+ on 16d octahedral site, so the Jahn Teller distortion is suppressed and the spinel skeleton structure is stabilized. Furthermore, Cr and Al maintain +3 valence at the process of 3.0-4.3V charge and discharge