Phenylphosphonate surface functionalisation of MgMn2O4with 3D open-channel nanostructures for composite slurry-coated cathodes of rechargeable magnesium batteries operated at room temperature

Koichi Kajihara, Daisuke Takahashi, Hiroaki Kobayashi, Toshihiko Mandai, Hiroaki Imai, Kiyoshi Kanamura

Research output: Contribution to journalArticlepeer-review

Abstract

Spinel-type MgMn2O4, prepared by a propylene-oxide-driven sol-gel method, has a high surface area and structured bimodal macro- and mesopores, and exhibits good electrochemical properties as a cathode active material for rechargeable magnesium batteries. However, because of its hydrophilicity and significant water adsorption properties, macroscopic aggregates are formed in composite slurry-coated cathodes when 1-methyl-2-pyrrolidone (NMP) is used as a non-aqueous solvent. Functionalising the surface with phenylphosphonate groups was found to be an easy and effective technique to render the structured MgMn2O4hydrophobic and suppress aggregate formation in NMP-based slurries. This surface functionalisation also reduced side reactions during charging, while maintaining the discharge capacity, and significantly improved the coulombic efficiency. Uniform slurry-coated cathodes with active material fractions as high as 93 wt% can be produced on Al foils by this technique employing carbon nanotubes as an electrically conductive support. A coin-type full cell consisting of this slurry-coated cathode and a magnesium alloy anode delivered an initial discharge capacity of ∼100 mA h g−1at 25 °C.

Original languageEnglish
Pages (from-to)19076-19082
Number of pages7
JournalRSC Advances
Volume11
Issue number31
DOIs
Publication statusPublished - 2021 May 19

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

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