Understanding the Influence of Composition and Synthesis Temperature on Oxygen Loss, Reversible Capacity, and Electrochemical Behavior of xLi(2)MnO(3)-(1-x)LiCoO2 Cathodes in the First Cycle

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

来源：Journal of Physical Chemistry C, 2014, 118(41): 23553-23558.

DOI：10.1021/jp507687h

• Discharge capacities
• Electrochemical behaviors
• Irreversible capacity loss
• Lithium-ion battery
• Lithium-rich layered oxides
• Reversible capacity
• Synthesis temperatures
• Two-step reactions

With an aim to broaden the understanding of the role of Co3+ in the lithium-rich layered oxide cathodes for lithium-ion batteries, the influence of composition and synthesis temperature on the oxygen loss, reversible capacity, and electrochemical behavior of the xLi(2)MnO(3)-(1 x)LiCoO2 series in the first cycle has been systematically investigated. The charge capacity first increases with increasing x value from 0.2 to 0.6 due to the enhanced oxygen loss, but then decreases with further increase in x from 0.6 to 0.8. Although the discharge capacity shows a trend similar to the charge capacity, the maximum value appears at x = 0.40.5, rather than at x = 0.6 because of its larger irreversible capacity loss. Surprisingly, raising the synthesis temperature from 800 to 1000 degrees C alters the electrochemical behavior of the first charge. The materials synthesized at 900 and 1000 degrees C show a three-step reaction process consisting of the oxidation of Co3+, simultaneous oxidation of Co3+ and O-2, and finally the oxidation of O-2 only, while those synthesized at 800 degrees C exhibit a two-step reaction process composed of Co3+ oxidation and O-2 oxidation occurring separately.

• 出版日期2014-10-16
• 单位华南理工大学