Asymmetric Lithium Extraction and Insertion in High Voltage Spinel at Fast Rate

Muhammad Mominur Rahman; Kangxuan Xia; Xiao-Qing Yang; Kingo Ariyoshi; Enyuan Hu

doi:10.1021/acs.nanolett.3c02042

Asymmetric Lithium Extraction and Insertion in High Voltage Spinel at Fast Rate

Nano Lett. 2023 Aug 9;23(15):7135-7142. doi: 10.1021/acs.nanolett.3c02042. Epub 2023 Jul 18.

Authors

Muhammad Mominur Rahman¹, Kangxuan Xia¹, Xiao-Qing Yang¹, Kingo Ariyoshi², Enyuan Hu¹

Affiliations

¹ Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States.
² Department of Chemistry and Bioengineering, Graduate School of Engineering, Osaka Metropolitan University, Osaka 558-8585, Japan.

PMID: 37462326
DOI: 10.1021/acs.nanolett.3c02042

Abstract

Spinel-structured ordered-LiNi_0.5Mn_1.5O₄ (o-LNMO) has experienced a resurgence of interest in the context of reducing scarce elements such as cobalt from the lithium-ion batteries. O-LNMO undergoes two two-phase reactions at slow rates. However, it is not known if such phenomenon also applies at fast rates. Herein, we investigate the rate-dependent phase transition behavior of o-LNMO through in operando time-resolved X-ray diffraction. The results indicate that a narrow region of the solid solution reaction exists for charge and discharge at both slow and fast rates. The overall phase transition is highly asymmetric at fast rates. During fast charge, it is a particle-by-particle mechanism resulting from an asynchronized reaction among the particles. During fast discharge, it is likely a core-shell mechanism involving transition from Li_0+xNi_0.5Mn_1.5O₄ to Li_1+xNi_0.5Mn_1.5O₄ in the outer layer of particles. The Li_0.5Ni_0.5Mn_1.5O₄ phase is suppressed during fast discharge and appears only through Li redistribution upon relaxation.

Keywords: fast charge; high voltage cathode; in situ XRD; ordered-LiNi0.5Mn1.5O4; phase transition.