Surface Doping to Enhance Structural Integrity and Performance of Li‐Rich Layered Oxide,Advanced Energy Materials

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Surface Doping to Enhance Structural Integrity and Performance of Li‐Rich Layered Oxide
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2018-10-03 , DOI: 10.1002/aenm.201802105
Shuai Liu _{1,

2} , Zepeng Liu _{1,

2} , Xi Shen ₃ , Weihan Li ₄ , Yurui Gao ₅ , Mohammad Norouzi Banis ₄ , Minsi Li ₄ , Kai Chen ₆ , Liang Zhu _{2,

7} , Richeng Yu _{2,

3} , Zhaoxiang Wang _{1,

2} , Xueliang Sun ₄ , Gang Lu ₅ , Qingyu Kong ₆ , Xuedong Bai ₇ , Liquan Chen _{1,

2}

Affiliation

The Li‐rich layer‐structured oxides are regarded as one of the most promising cathode materials for their high energy density but suffer from severe problems such as capacity fading, poor rate performance, and continuous potential dropping. These issues are addressed here by surface doping of niobium (Nb) and other heavy ions in a Li‐rich Mn‐based layered oxide, Li_1.2Mn_0.54Ni_0.13Co_0.13O₂. The doped ions are verified to be located in the Li‐layer near the oxide surface; they bind the slabs via the strong NbO bonds and “inactivate” the surface oxygen, enhancing the structural stability. The specific capacity of the modified oxide reaches 320 mAh g⁻¹ in the initial cycle, 94.5% of which remains after 100 cycles. More importantly, the average discharge potential drops only by 136 mV in this process. The findings of this study illustrate the importance of inactivating the surface oxygen in suppressing the cation mixing in the bulk, providing an effective strategy for designing high‐performance Li‐rich cathode materials.

中文翻译：

表面掺杂可增强富锂层状氧化物的结构完整性和性能

富锂层状氧化物因其高能量密度而被认为是最有前途的阴极材料之一，但遇到严重的问题，例如容量下降，速率性能差和电位连续下降。这些问题可通过在富Li的Mn_基层状氧化物Li _1.2 Mn _0.54 Ni _0.13 Co _0.13 O _2中对铌（Nb）和其他重离子进行表面掺杂来解决。掺杂离子被证实位于氧化层附近的锂层中。它们通过强大的NbO键将平板结合起来，并使表面氧“失活”，从而增强了结构稳定性。改性氧化物的比容量达到320 mAh g ^-1在初始循环中，其中94.5％在100次循环后仍保留。更重要的是，在此过程中，平均放电电势仅下降了136 mV。这项研究的结果表明，灭活表面氧对抑制本体中的阳离子混合非常重要，为设计高性能的富锂阴极材料提供了有效的策略。

更新日期：2018-10-03

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