Lithium-rich materials possess the ultra-high specific capacity, but the redox of oxygen is not completely reversible, resulting in voltage attenuation and structural instability. A stepwise co-precipitation method is used for the first time in this paper to achieve the control of the two-phase distribution through controlling the distribution of transition metal elements and realize the modification of particle surface struc-ture without the aid of heterologous ions. The results of characterization tests show that the content of LiMO2 phase inside the particles and the content of Li2MnO3 phase on the surface of the particles are successfully increased, and the surface induced formation of Li4Mn5O12 spinel phase or some disorderly ternary. The electrochemical performance of the modified sample is as follows: LR (pristine) shows specific dis-charge capacity of 72.7 mA·h·g?1 after 500 cycles at 1 C, while GR (modified sample) shows specific discharge capacity of 137.5 mA·h·g?1 at 1 C, and the discharge mid-voltage of GR still remains above 3 V when cycling to 220 cycles at 1 C (mid-voltage of LR remains above 3 V when cycling to 160 cycles at 1 C). Therefore, deliberately regulating the local state of the two phases is a successful way to reinforced the ma-terial structure and inhibition the voltage attenuation.

Yang Yu;Jianling Li;Guimei Han;Zhe Yang;Jianjian Zhong;Feiyu Kang

State Key Laboratory of Advanced Metallurgy,School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;Chinese Research Academy of Environmental Sciences,Beijing 100012,China;School of Materials Science and Engineering,Tsinghua University,Beijing 100084,China

矿物冶金与材料学报

[1]Yang Yu;Jianling Li;Guimei Han;Zhe Yang;Jianjian Zhong;Feiyu Kang-.Optimize two-phase distribution of lithium-rich materials to stabilize structure and suppress voltage attenuation)[J].矿物冶金与材料学报,2022(12):2201-2211

Li4Mn5O12,disorderly

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