Charge-discharge properties and reaction mechanism of cation-disordered rutile-type Li1.2MnFe1.2F6.8
Charge-discharge properties and reaction mechanism of cation-disordered rutile-type Li1.2MnFe1.2F6.8
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DOI：
10.1016/j.electacta.2021.139627
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发表时间：
2021-11
影响因子：
6.6
通讯作者：
Yayun Zheng;Jinkwang Hwang;K. Matsumoto;R. Hagiwara
中科院分区：
文献类型：
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作者：
Yayun Zheng;Jinkwang Hwang;K. Matsumoto;R. Hagiwara
首次提出了一种具有阳离子无序金红石结构的碳包覆li1.2 mnfe1.2 f6.8作为锂离子电池正极材料。为了提高性能，使用热稳定的离子液体电解质在90°C下对复合电极进行了研究。同步x射线衍射、x射线光电子能谱和半电池测试相结合，在2.5 ~ 4.5 V电压范围内，90°C下，锂从li1.2 mnfe1.2 f6.8中可逆提取/插入，涉及Fe(III)/Fe（II）和Mn(III)/Mn（II）氧化还原反应，以及金红石li1.2 mnfe1.2 f6.8与LiF和金红石FeF2混合物之间的部分转化反应。深度放电至2.0 V时，LiF和金属Fe、Mn发生转化反应，金红石结构部分保留。
A carbon-coated Li1.2MnFe1.2F6.8with a cation-disordered rutile structure is presented for the first time as a positive electrode material for lithium-ion batteries. For improved performance, the composite electrode is investigated at 90 °C using a thermally stable ionic liquid electrolyte. A combination of synchrotron X-ray diffraction, X-ray photoelectron spectroscopy and half-cell tests establish that the reversible extraction/insertion of lithium from/into Li1.2MnFe1.2F6.8in the 2.5–4.5 V voltage range at 90 °C involves Fe(III)/Fe(II) and Mn(III)/Mn(II) redox reactions alongside partial conversion reactions between the rutile Li1.2MnFe1.2F6.8and a mixture of LiF and rutile FeF2. Deep discharge to 2.0 V involves a conversion reaction to LiF and metallic Fe and Mn accompanied by the partial preservation of the rutile structure.