Variation of Li diffusion Coefficient during delithiation of Spinel LiNi0.5Mn1.5O4

Rahim, Ahmad Syahmi Abdul and Kufian, Mohd Zieauddin and Arof, Abdul Kariem Mohd and Osman, Zurina (2022) Variation of Li diffusion Coefficient during delithiation of Spinel LiNi0.5Mn1.5O4. Journal of Electrochemical Science and Technology, 13 (1). pp. 128-137. ISSN 2093-8551, DOI https://doi.org/10.33961/jecst.2021.00780.

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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.

Item Type: Article
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 ]
Uncontrolled Keywords: Spinel LiNi0.5Mn1.5O4; Li Diffusion Coefficient; Phase Transformation; Oxidation State; GITT Method
Subjects: Q Science > QD Chemistry
Divisions: Faculty of Science > Department of Physics
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 08 Aug 2022 01:56
Last Modified: 08 Aug 2022 01:56
URI: http://eprints.um.edu.my/id/eprint/33433

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