材料科学
阴极
钴
兴奋剂
电解质
化学工程
氧化物
氧化钴
钝化
锂(药物)
镍
电极
纳米技术
光电子学
物理化学
冶金
内分泌学
化学
工程类
医学
图层(电子)
作者
Yu Shen,Xiaojing Yao,Shaohua Wang,Dongyu Zhang,Dongming Yin,Limin Wang,Yong Cheng
标识
DOI:10.1021/acsami.1c20568
摘要
High-voltage high-nickel low-cobalt lithium layered oxide cathodes show great application prospects for lithium-ion batteries due to their low cost and high capacity. However, deterioration of the bulk structure and the electrode-electrolyte interface will significantly endanger the cycle life and thermal stability of the battery as the nickel content and voltage increase. We present here a lattice doping strategy to greatly improve the cell performance by doping a small dose of Ti (2 mol %) in LiNi0.6Co0.05Mn0.35O2. Through density functional theory calculations, we know that the diffusion energy barrier of Li+ decreases and the activation energy of surface lattice oxygen atom loss increases after Ti doping, thereby improving the rate performance and inhibiting the undesired phase transition. The battery in situ X-ray diffraction (XRD) pattern demonstrates that Ti doping tunes the H1-H2 phase-transition process from a two-phase reaction to a single-phase reaction and inhibits the undesired H2-H3 phase transition, minimizing the mechanical degradation. The variable temperature in situ XRD reveals delayed phase-transition temperature to improve thermal stability. These improvements can be attributed to Ti doping to passivate the reactivity of the layered oxide cathode, which is fundamentally related to the strong Ti-O bond and no unpaired electrons for Ti4+. This work provides valuable strategic guidelines for the use of high-voltage high-nickel low-cobalt cathodes in lithium-ion batteries.
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