Entropy and Electronic Structure Modulation of a Prussian Blue Analogue Cathode with Suppressed Phase Evolution for Potassium-Ion Batteries

Shuangyan Qiao, Qianwen Zhou, Hua Kun Liu, Shi Xue Dou, Shaokun Chong

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Severe structural evolution and high content of [Fe(CN)6]4- defects drastically deteriorate K-ion storage performances of Prussian blue-based cathodes. Herein, a potassium manganese iron copper hexacyanoferrate (KFe2/3Mn1/6Cu1/6HCF), with suppressed anionic vacancies, eliminated band gap, and low K-ion diffusion barrier, is regarded as a cathode for potassium-ion batteries. The entropy stabilization effect and robust Cu-N bond induced by the inert Cu-ion with large electronegativity boost KFe2/3Mn1/6Cu1/6HCF to exhibit great phase state stability, thus inhibiting the structural transition of monoclinic ↔ cubic. Hence, KFe2/3Mn1/6Cu1/6HCF undergoes a zero-stress solid-solution reaction mechanism, where Fe and Mn serve as dual active sites for charge compensation. Consequently, KFe2/3Mn1/6Cu1/6HCF displays a high reversible capacity of 127.5 mAh·g-1 with an energy density of 469.2 Wh·kg-1 at 10 mA·g-1 and superior cyclic stability with a high retention of 90.7% over 100 cycles. A high-energy-density K-ion full battery is assembled, contributing an ultralong lifetime over 1000 cycles with a low-capacity fading rate of 0.038% per cycle.

Original languageEnglish
Pages (from-to)15167-15177
Number of pages11
JournalNano Letters
Volume24
Issue number47
DOIs
StatePublished - 27 Nov 2024

Keywords

  • Cathode materials
  • Phase transition mechanism, Entropy
  • Potassium-ion batteries
  • Prussian blue

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