Chemistry and Chemical Biology ETDs

Publication Date

Summer 7-28-2026

Abstract

Cation-disordered rock-salt (DRX) cathodes provide a highly tunable platform for next-generation Li- and Na-ion batteries, but their electrochemical behavior is strongly influenced by local structural features hidden in average crystal structures. This dissertation systematically investigates local cation ordering in Li- and Na-based DRX cathodes to understand its effects on Li+/Na+ transport, redox activity, structural evolution, and electrochemical performance. In Li-based systems, Raman spectroscopy and electrochemical analysis reveal that local layered cation ordering in Mn- and Fe-based DRX cathodes is closely correlated with electrochemical behavior. Over-stoichiometric Li-based DRX oxyfluorides further demonstrate that excess Li can regulate local cation ordering, improve Li+ transport pathways, and enhance performance. A partially disordered zigzag-type Li–Nb–Mn–O cathode connects ordered zigzag-type structures with fully disordered DRX frameworks. In Na-based systems, metastable Na–Ti–Mn–O DRXs demonstrate that local cation ordering is strongly associated with anionic oxygen redox activation and Na-ion utilization. Overall, these findings establish local cation ordering as a critical design factor governing ion diffusion, redox chemistry, structural stability, and electrochemical performance, and highlight local-structure control as a promising strategy for designing high-performance Li- and Na-ion battery cathodes.

Project Sponsors

The University of New Mexico, NSF

Language

English

Keywords

Li-ion Battery, Na-ion Battery, Cathode, Disordered Rock Salt, Local Cation Ordering

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Dongchang Chen

Second Committee Member

Terefe G. Habteyes

Third Committee Member

Jeffrey J. Rack

Fourth Committee Member

Yi He

Fifth Committee Member

Shuya Wei

Comments

The first revised version of Manuscript.

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