Effect of Particle Size and Anion Vacancy on Electrochemical Potassium Ion Insertion into Potassium Manganese Hexacyanoferrates

Tomooki Hosaka, Taiga Fukabori, Haruka Kojima, Kei Kubota, Shinichi Komaba

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Potassium manganese hexacyanoferrate (KMnHCF) can be used as a positive electrode for potassium-ion batteries because of its high energy density. The effect of particle size and [Fe(CN)6]n− vacancies on the electrochemical potassium insertion of KMnHCFs was examined through experimental data and theoretical calculations. When nearly stoichiometric KMnHCF was synthesized and tested, smaller particle sizes were found to be important for achieving superior electrochemical performance in terms of capacity and rate capability. However, even in the case of larger particles, introducing a suitable number of anion vacancies enabled KMnHCF to exhibit comparable electrode performance. Electrochemical tests and density functional theory calculations indicated that anion vacancies contribute to the enhancement of K+ ion diffusion, which realizes good electrochemical performance. Structural design, including crystal vacancies and particle size, is the key to their high performance as a positive electrode.

Original languageEnglish
Pages (from-to)1166-1175
Number of pages10
JournalChemSusChem
Volume14
Issue number4
DOIs
Publication statusPublished - 18 Feb 2021

Keywords

  • Prussian blue analogues
  • batteries
  • insertion materials
  • ionic diffusion
  • potassium

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