Evolution of redox couples in Li- and Mn-rich cathode materials and mitigation of voltage fade by reducing oxygen release

被引：877

作者：

Hu, Enyuan ^{[1
]}

Yu, Xiqian ^{[1
,2
]}

Lin, Ruoqian ^{[1
,3
]}

Bi, Xuanxuan ^{[4
]}

Lu, Jun ^{[4
]}

Bak, Seongmin ^{[1
]}

Nam, Kyung-Wan ^{[5
]}

Xin, Huolin L. ^{[3
]}

Jaye, Cherno ^{[6
]}

Fischer, Daniel A. ^{[6
]}

Amine, Kahlil ^{[4
]}

Yang, Xiao-Qing ^{[1
]}

机构：

[1] Brookhaven Natl Lab, Div Chem, Upton, NY 11973 USA

[2] Chinese Acad Sci, Inst Phys, Beijing Natl Lab Condensed Matter Phys, Beijing, Peoples R China

[3] Brookhaven Natl Lab, Ctr Funct Nanomat, Upton, NY 11973 USA

[4] Argonne Natl Lab, Chem Sci & Engn Div, 9700 S Cass Ave, Argonne, IL 60439 USA

[5] Dongguk Univ Seoul, Dept Energy & Mat Engn, Seoul, South Korea

[6] NIST, Mat Measurement Lab, Gaithersburg, MD 20899 USA

来源：

NATURE ENERGY | 2018年 / 3卷 / 08期

基金：

中国国家自然科学基金; 新加坡国家研究基金会; 国家重点研发计划;

关键词：

POSITIVE-ELECTRODE MATERIALS; RAY-ABSORPTION SPECTROSCOPY; LAYERED COMPOSITE CATHODE; LITHIUM-ION BATTERIES; THERMAL-STABILITY; DEFECT STATES; INTERFACE; CAPACITY; DIFFRACTION; ORIGIN;

D O I：

10.1038/s41560-018-0207-z

中图分类号：

TE [石油、天然气工业]; TK [能源与动力工程];

学科分类号：

0807 ; 0820 ;

摘要：

Voltage fade is a major problem in battery applications for high-energy lithium- and manganese-rich (LMR) layered materials. As a result of the complexity of the LMR structure, the voltage fade mechanism is not well understood. Here we conduct both in situ and ex situ studies on a typical LMR material (Li1.2Ni0.15Co0.1Mn0.55O2) during charge-discharge cycling, using multi-lengthscale X-ray spectroscopic and three-dimensional electron microscopic imaging techniques. Through probing from the surface to the bulk, and from individual to whole ensembles of particles, we show that the average valence state of each type of transition metal cation is continuously reduced, which is attributed to oxygen release from the LMR material. Such reductions activate the lower-voltage Mn3+/Mn4+ and Co2+ /Co3+ redox couples in addition to the original redox couples including Ni2+/Ni3+, Ni3+/Ni4+ and O2-/O-, directly leading to the voltage fade. We also show that the oxygen release causes microstructural defects such as the formation of large pores within particles, which also contributes to the voltage fade. Surface coating and modification methods are suggested to be effective in suppressing the voltage fade through reducing the oxygen release.

引用

页码：690 / 698

页数：9

共 54 条

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