First-Principles Investigation on Delithiation Mechanisms in a Li-Rich Monoclinic Li2MoO3 Cathode Material for Li-Ion Batteries

Anu Maria Augustine; Vishnu Sudarsanan; Ponniah Ravindran

doi:10.1021/acs.inorgchem.3c01331

First-Principles Investigation on Delithiation Mechanisms in a Li-Rich Monoclinic Li₂MoO₃ Cathode Material for Li-Ion Batteries

Inorg Chem. 2023 Sep 4;62(35):14191-14206. doi: 10.1021/acs.inorgchem.3c01331. Epub 2023 Aug 19.

Authors

Anu Maria Augustine^{1

2}, Vishnu Sudarsanan^{1

2}, Ponniah Ravindran^{1

2}

Affiliations

¹ Department of Physics, Central University of Tamil Nadu, Thiruvarur 610005, India.
² Simulation Center for Atomic and Nanoscale MATerials (SCANMAT), Central University of Tamil Nadu, Thiruvarur, Tamil Nadu 610005, India.

PMID: 37596981
DOI: 10.1021/acs.inorgchem.3c01331

Abstract

Li₂MoO₃ is a promising cathode material for high-capacity Li-ion batteries. However, during cycling, migration of Mo to Li sites results in capacity fading. The present study analyzed structural, electronic, electrochemical, and mechanical characteristics of ordered monoclinic C2/m-Li₂MoO₃ and found that this phase has improved electrochemical properties compared to the rhombohedral R3̅m phase. Nudged elastic band calculations showed that Mo migration to the Li site is less probable in C2/m-Li₂MoO₃. The charge and chemical bonding analyses during delithiation showed Mo⁴⁺/Mo⁶⁺ oxidation and partial oxygen oxidation, but no spontaneous oxygen release occurred. The voltage profile calculated using the SCAN + U method exhibits high voltage, and partial W substitution at Mo sites suppresses intralayer Mo migration to the Li site and improves the voltage characteristics. These findings suggest that monoclinic Li₂MoO₃ is a potential cathode material for high-capacity Li-ion batteries with reduced Mo migration and maintained Mo⁴⁺/Mo⁶⁺ oxidation and oxygen stability. Moreover, partial W substitution at Mo sites further enhances the electrochemical properties of C2/m-Li₂MoO₃.