Reversible Mn/Cr dual redox in cation-disordered Li-excess cathode materials for stable lithium ion batteries. (15th June 2021)

• Record Type: Journal Article
• Authors: Zheng, Xuerong; Xu, Zhengrui; Li, Shaofeng; Zhang, Yuxin; Zhang, Jinfeng; Kuai, Chunguang; Tao, Lei; Rahman, Muhammad Mominur; Zhang, Yan; Lee, Sang-Jun; Sun, Cheng-Jun; Li, Luxi; Hu, Wenbin; Nordlund, Dennis; Liu, Jue; Liu, Yijin; Lin, Feng
• Is Part Of: Acta materialia. Volume 212(2021)
• Publication Date: 2021-06-15
• Subjects: Disordered rocksalt -- High rate capability -- Long cycle life -- Dual redox -- Li ion battery; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2021.116935
• Languages: English
• ISSNs: 1359-6454

Abstract

Graphical abstract: Image, graphical abstract Abstract: Cation-disordered Li-excess oxides/oxyfluorides have opened the door for designing alternative, high energy cathodes. However, achieving long cycle life and high rate capability represents a major challenge for disordered rocksalt cathodes (DRX). Herein, we develop Li2 Mn3/4 Cr1/4 O2 F (LMCOF) DRX materials through a distinct redox mechanochemical method. The LMCOF contains trivalent Cr 3+ and Mn 3+, which allows for simultaneously accessing stable Mn/Cr dual redox at a narrow voltage window acceptable for conventional carbonate electrolytes. Coupled with the mitigated and reversible oxygen chemical changes, the LMCOF delivers high capacity, rate capability, as well as long cycle life upon extensive 1, 000 cycles at various current densities. The multiscale synchrotron and neutron scattering, spectroscopic, and imaging analyses demonstrate that the capacity originates from the Mn/Cr dual redox with minimal contribution from oxygen redox, and that the good cycle life is attributed to the stable global crystal structure and local oxygen chemical environment.