X-ray Absorption Spectroscopy Illustrates the Participation of Oxygen in the Electrochemical Cycling of Li4Mn2O5

13 September 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

A combination of oxygen redox and Mn-based oxides would be the best option for high-energy density Li-ion batteries crucial for a sustainable society. The disordered rock-salt Li4Mn2O5 was recently reported to display very large capacity of 460 mAh/g with relative reversibility. Previous studies proposed the involvement of lattice oxygen redox in such intriguing electrochemical performance, whereas no direct evidence was presented. To clarify the charge compensation mechanism, we systematically investigated the evolution of the electronic structure of both Mn and O upon cycling via Mn/O K-edge XAS spectroscopy. Mn K-edge XAS unequivocally demonstrates the participation of Mn redox upon the initial stages of charging, yet changes are arrested at the high potentials, while O continues to evolve according to O K-edge XAS. Upon discharging, both Mn and O partially recover to their pristine states. The results highlight the significance of a disordered structure in maintaining the reversible redox chemistry of both transition metals and oxygen to design cathode materials with high energy density.

Keywords

Li4Mn2O5
X-ray absorption spectroscopy
Oxygen involvement
Charge compensation mechanism

Supplementary materials

Title
Description
Actions
Title
The Supporting Information is available free of charge.
Description
Figures S1-S5 and Table S1. Supplementary X-ray diffraction patterns, additional analysis of XAS
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.