Effect of Co content on performance of LiAl_(1/3-x)Co_xNi_(1/3)Mn_(1/3)O_2 compounds for lithium-ion batteries

摘要

Layered LiAl_(1/3-x)Co_xNi_(1/3)Mn_(1/3)O_2 (O < = x < = 1/3) compounds were studied via the combination of computational and experimental approach. The calculated voltage curve of LiNi_(1/3)Al_(1/3)Mn_(1/3)O_2 compound is presented, indicating it is of great potential for a cathode material of lithium-ion batteries. Unfortunately, it was found that the LiNi_(1/3)Al_(1/3)Mn_(1/3)O_2 compound without impurity phase could not be synthesized via a sol-gel process. To obtain a layered compound without impurity phase, partial of Al is replaced by Co in LiNi_(1/3)Al_(1/3)Mn_(1/3)O_2 compound in this study. Layered LiAl_(1/3-x)Co_xNi_(1/3)Mn_(1/3)O_2 (0 < = x < = 1/3) compounds were synthesized via sol-gel reaction at 900 deg C under a oxygen stream. Single phase of the LiAl_(1/3-x)Co_xNi_(1/3)Mn_(1/3)O_2 in 1/6 < = x < = 1/3 region could be prepared successfully. The discharge capacity and conductivity increased with an increase in the Co-substitution content. The enhancement of the conductivity and phase purity by the introduction of Co content shows profound influence on the performance of the LiAl_(1/3-x)Co_xNi_(1/3)Mn_(1/3)O_2 compounds.