Rational design of mechanically robust Ni-rich cathode materials via concentration gradient strategy

• Published in: Nature communications Vol. 12; no. 1; pp. 6024 - 10
• Main Authors: Liu, Tongchao, Yu, Lei, Lu, Jun, Zhou, Tao, Huang, Xiaojing, Cai, Zhonghou, Dai, Alvin, Gim, Jihyeon, Ren, Yang, Xiao, Xianghui, Holt, Martin V., Chu, Yong S., Arslan, Ilke, Wen, Jianguo, Amine, Khalil
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.10.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 147/143; 639/301/299/161; 639/301/299/891; 639/4077/4079/891; 639/638/675; Cathodes; Cobalt; Concentration gradient; Design; Electrochemistry; Electrode materials; Electrolytes; Humanities and Social Sciences; Investigations; Laboratories; Lithium-ion batteries; Manganese; MATERIALS SCIENCE; Mechanical properties; Morphology; multidisciplinary; Nickel; Phase transitions; Rechargeable batteries; Science; Science (multidisciplinary); Stability analysis; Stiffness; Structural integrity
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-26290-z

Mechanical integrity issues such as particle cracking are considered one of the leading causes of structural deterioration and limited long-term cycle stability for Ni-rich cathode materials of Li-ion batteries. Indeed, the detrimental effects generated from the crack formation are not yet entirely addressed. Here, applying physicochemical and electrochemical ex situ and in situ characterizations, the effect of Co and Mn on the mechanical properties of the Ni-rich material are thoroughly investigated. As a result, we successfully mitigate the particle cracking issue in Ni-rich cathodes via rational concentration gradient design without sacrificing the electrode capacity. Our result reveals that the Co-enriched surface design in Ni-rich particles benefits from its low stiffness, which can effectively suppress the formation of particle cracking. Meanwhile, the Mn-enriched core limits internal expansion and improve structural integrity. The concentration gradient design also promotes morphological stability and cycling performances in Li metal coin cell configuration. Mechanical integrity issues are one of the main causes of limited long-term cycle stability for Ni-rich cathode materials. Here the authors analyse the roles of cobalt and manganese and utilise a concentration gradient design to mitigate these issues.