一些金属阳离子的掺杂对尖晶石LiMn2O4的结构和电化学性质的影响

介绍了Co、Cr、Ni、Cu、Al 5种金属元素的掺杂对尖晶石LiMn2 O4 的结构和 4V区电化学性质的影响 :探讨了掺杂元素增加尖晶石锂锰氧化物 4V区循环稳定性的机理 ;减少了尖晶石在电解液中的溶解量 ;抑制了John Teller效应的发生 ;增加了键强度 ,使得尖晶石结构更加牢固。讨论了掺杂对尖晶石高电位 (>4 5V)区容量的影响 :掺杂后的尖晶石锂锰氧化物仍保持尖晶石结构 ,但与未掺杂的尖晶石锂锰氧化物相比 ,它的晶胞常数减小 ,晶胞体积收缩 ;锰元素的平均化合价升高 ;4V区的初始容量减小 ;循环稳定性明显增加。除Al外 ,Co、Cr、Ni、Cu掺杂后的尖晶石锂锰氧化物均在高电位区有一定的放电容量 ,且随掺杂量的增加而增加。

Effects of Doped Metal Elements on the Structure and the Electrochemical Performances of Spinel Lithium Manganese Oxide

The structure and the electrochemical performances of Co, Cr, Ni, Cu, Al doped spinel lithium manganese oxides in the 4 V range are introduced. Compared with pure spinel LiMn 2O 4, the doped oxides still have spinel structure. With increasing dopant content, their lattice constants and cell volume decrease, average valence of Mn increases, and initial specific capacity in 4 V range decreases. The doped oxides have better cyclability. The mechanisms of performance change in doped spinel LiMn 2O 4 are discussed: With the doped elements, the dissolution of spinel lithium manganese oxide into electrolyte is inhibited, John Teller distortion is suppressed, and spinel skeleton is strengthed. Charge and discharge behaviors in high voltage range(>4 5 V) of doped spinel lithium manganese oxide is also discussed: Except for Al, Co, Cr, Ni and Cu doped spinel LiMn 2O 4 have a high volt plateau and the specific capacity of this plateau increases with increasing dopant content.