A multifunctional manipulation to stabilize oxygen redox and phase transition in 4.6 V high-voltage LiCoO2 with sXAS and EPR studies
A multifunctional manipulation to stabilize oxygen redox and phase transition in 4.6 V high-voltage LiCoO2 with sXAS and EPR studies
复制标题
通过 sXAS 和 EPR 研究，实现稳定 4.6 V 高压 LiCoO2 中氧氧化还原和相变的多功能操作
DOI：
10.1016/j.jpowsour.2021.230661
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发表时间：
2021
影响因子：
9.2
通讯作者：
Hu Bingwen
中科院分区：
文献类型：
--
作者：
Hu Bei;Geng Fushan;Shen Ming;Zhao Chong;Qiu Qing;Lin Yang;Chen Changxin;Wen Wen;Zheng Shun;Hu Xiaoshi;Li Chao;Hu Bingwen
LiCoO2 作为锂离子电池的域正极材料，由于高电压（>4.35 Vvs.Li/Li+）下循环稳定性有限，面临着巨大的挑战。这些问题暂时通过多功能自稳定改性策略得到解决，包括微量镁体掺杂、表面梯度钛掺杂和 LiCoO2 中的 BaTiO3 点涂层。经过验证，多功能协同作用可以克服 LiCoO2 在 4.6 V 下循环时不利的不可逆相变和阻抗增长。通过使用软 X 射线吸收光谱 (sXAS) 和电子顺磁共振 (EPR) 技术，我们还阐明 Ti 表面梯度掺杂可以增强颗粒的结构刚性，同时显着减弱高电压下的不可逆氧氧化还原。所有这些策略都通过不同的机制促进了 LiCoO2 在 4.6 V 高电压下的长期循环性能。这项详尽的研究为高压 LiCoO2 的发展提供了指导性贡献。
LiCoO2, as a domain cathode material of Li-ion batteries, faces a great deal of challenges due to the limited cycling stability at high voltage (>4.35 Vvs.Li/Li+). These issues are tentatively addressed here by a multifunctional self-stabilization modification strategy, involving trace Mg bulk doping, surface gradient Ti doping and BaTiO3dot coating in LiCoO2. The multifunctional synergy is verified to overcome the detrimental irreversible phase transition and the growth of impedance of LiCoO2cycling at 4.6 V. By using soft X-ray absorption spectroscopy (sXAS) and electron paramagnetic resonance (EPR) techniques, we also elucidate that Ti surface gradient doping can reinforce the structure rigidity of the particles while significantly attenuates the irreversible oxygen redox at high voltage. All these strategies promote the prolonged cyclic performance of LiCoO2under 4.6 V high-voltage through different mechanism. This elaborate investigation provides an instructive contribution in the advancement of high-voltage LiCoO2.