Variation of Li diffusion Coefficient during delithiation of Spinel LiNi0.5Mn1.5O4
Document Type
Article
Publication Date
2-1-2022
Abstract
For this study, the sol gel method was used to synthesize the spinel LiNi0.5Mn1.5O4 (LNMO) electrode material. Structural, morphological, electrochemical, and kinetic aspects of the LNMO have been characterized. The synthesized LNMO was indexed with the Fd (3) over barm cubic space group. The excellent capacity retention indicates that the spinel framework of LNMO has the ability to withstand high rate charge-discharge throughout long cycle tests. The Li diffusion coefficient (D-Li) changes non-monotonically across three orders of magnitude, from 10(-9) to 10(-12) cm(2) s(-1) determined from GITT method. The variation of D-Li seemed to be related to three oxidation reactions that happened throughout the charging process. A small dip in D-Li at the beginning stage of Li deintercalation is correlated with the oxidation of Mn3+ to Mn4+. While two pronounced D-Li minima at 4.7 V and 4.75 V are due to the oxidation of Ni2+/Ni3+ and Ni3+/Ni4+ respectively. The depletion of D-Li at the high voltage region is attributed to the occurrence of two successive phase transformation phenomena.
Keywords
Spinel LiNi0.5Mn1.5O4, Li Diffusion Coefficient, Phase Transformation, Oxidation State, GITT Method
Divisions
PHYSICS
Funders
Ministry of Energy, Science, Technology, Environment and Climate Change (MESTECC), Malaysia [53-02-03-1089],Universiti Malaya (Industry-Driven Innovation) [PPSI-2020-CLUSTER-IDIG05 ]
Publication Title
Journal of Electrochemical Science and Technology
Volume
13
Issue
1
Publisher
Korean Electrochemistry Soc
Publisher Location
ROOM 1715, 122 WANGSAN-RO, DONGDAEMUN-GU, SEOUL, 130-070, SOUTH KOREA