Understanding the Effect of Co3 Substitution on the Electrochemical Properties of Lithium-Rich Layered Oxide Cathodes for Lithium-Ion Batteries

作者：Xiang, Xingde; Knight, James C; Li, Weishan; Manthiram, Arumugam^*

来源：Journal of Physical Chemistry C, 2014, 118(38): 21826-21833.

DOI：10.1021/jp506731v

• Capacity fade
• Discharge voltages
• Electrochemical charge/discharge
• First discharge
• Lithium-ion battery
• Lithium-ion cells
• Lithium-rich layered oxides
• Reversible capacity

The effect of the substitution of Co3 for equal amounts of Mn4 and Ni2 in the lithium-rich layered oxide cathode Li[Li0.2Ni0.2-x/2Mn0.6-x/2Cox]O-2 (0 <= x <= 0.24) has been investigated systematically. Electrochemical charge/discharge measurements in lithium-ion cells indicate that the oxygen loss from the lattice during the first charge is a kinetically slow process, but it can be improved by the substitution of Co3 due to an overlap of the Co3 /4 :t(2g) band with the top of the O2-:2p band and an increase in metal-oxygen covalence. Although the increased oxygen loss with increasing Co3 substitution leads to a higher reversible capacity, the first cycle discharge voltage decreases slightly due to the higher concentration of Mn3 ions created during the first discharge. However, both the capacity fade and the voltage decay increase during extended cycling with increasing Co3 substitution due to an increasing migration of the transition-metal ions to the lithium layer, which is promoted by the higher number of oxide-ion vacancies in the lattice, to form a spinel-like phase.

• 出版日期2014-9-25
• 单位华南理工大学