Effect of Al substitution on structure and cathode performance of MgMn2O4 spinel for magnesium rechargeable battery

Rika Yokozaki, Hiroaki Kobayashi, Toshihiko Mandai, Itaru Honma

Research output: Contribution to journalArticlepeer-review

Abstract

Magnesium rechargeable batteries using Mg-metal anodes are promising post-lithium-ion batteries. MgMn2O4 is a strong candidate cathode material owing to its high energy density and relatively high Mg2+-ion diffusivity. However, while pristine MgMn2O4 forms a tetragonal spinel structure (I41/amd) owing to the Jahn–Teller effect of Mn3+, it adopts a cubic structure in the charged/discharged state. This results in a structural change from tetragonal to cubic during charge/discharge cycling, leading to poor battery performance and reversibility. To improve the cathode performance, we prepared Al-substituted MgMn2−xAlxO4 spinel (x = 0, 0.1, 0.2, 0.5) to suppress the Jahn–Teller distortion. The obtained MgMn2−xAlxO4 spinel is a two-phase crystal with coexisting tetragonal and cubic spinel structures, whereby the fraction of cubic phase tends to increase with the Al ratio. The Al-substituted spinels exhibit superior discharge capacities to that of MgMn2O4. The increase in cubic spinel phase fraction by Al-substitution and the reduced structural change during discharging will aid the development of superior cathodes for magnesium batteries.

Original languageEnglish
Article number159723
JournalJournal of Alloys and Compounds
Volume872
DOIs
Publication statusPublished - 2021 Aug 15

Keywords

  • Ceramics
  • Crystal structure
  • Energy storage materials
  • Sol-gel process

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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