尖晶石
材料科学
锂(药物)
钴
电化学
八面体
镍
密度泛函理论
无机化学
结晶学
晶体结构
电极
物理化学
计算化学
冶金
化学
内分泌学
医学
作者
Soo Jeong Kim,V. Hegde,Zhenpeng Yao,Zhi Lü,Maximilian Amsler,Jiangang He,Shiqiang Hao,Jason R. Croy,Eungje Lee,Michael M. Thackeray,Chris Wolverton
标识
DOI:10.1021/acsami.8b00394
摘要
Embedding a lithiated cobalt oxide spinel (Li2Co2O4, or LiCoO2) component or a nickel-substituted LiCo1–xNixO2 analogue in structurally integrated cathodes such as xLi2MnO3·(1–x)LiM′O2 (M′ = Ni/Co/Mn) has been recently proposed as an approach to advance the performance of lithium-ion batteries. Here, we first revisit the phase stability and electrochemical performance of LiCoO2 synthesized at different temperatures using density functional theory calculations. Consistent with previous studies, we find that the occurrence of low- and high-temperature structures (i.e., cubic lithiated spinel LT-LiCoO2; or Li2Co2O4 (Fd3̅m) vs trigonal-layered HT-LiCoO2 (R3̅m), respectively) can be explained by a small difference in the free energy between these two compounds. Additionally, the observed voltage profile of a Li/LiCoO2 cell for both cubic and trigonal phases of LiCoO2, as well as the migration barrier for lithium diffusion from an octahedral (Oh) site to a tetrahedral site (Td) in Fd3̅m LT-Li1–xCoO2, has been calculated to help understand the complex electrochemical charge/discharge processes. A search of LiCoxM1–xO2 lithiated spinel (M = Ni or Mn) structures and compositions is conducted to extend the exploration of the chemical space of Li–Co–Mn–Ni–O electrode materials. We predict a new lithiated spinel material, LiNi0.8125Co0.1875O2 (Fd3̅m), with a composition close to that of commercial, layered LiNi0.8Co0.15Al0.05O2, which may have the potential for exploitation in structurally integrated, layered spinel cathodes for next-generation lithium-ion batteries.
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