Potassium nickel hexacyanoferrate as cathode for high voltage and ultralong life potassium-ion batteries

Shaokun Chong, Yifang Wu, Shengwu Guo, Yongning Liu, Guozhong Cao

Research output: Contribution to journalArticlepeer-review

77 Scopus citations

Abstract

Potassium-ion batteries (KIBs) are considered as one of the most promising energy storage devices owing to the close redox potential to lithium, rich abundance and low cost potassium resource, promoting the exploration on cathode materials for K-ions storage. This paper reports a detailed experimental study on potassium nickel hexacyanoferrate, K1.81Ni[Fe(CN)6]0.97·0.086H2O (KNHCF), cathode for KIBs. KNHCF synthesized possesses few [Fe(CN)6]4- vacancies and coordinated water molecules, and high specific surface area along with developed microporous/mesoporous structures, which collectively induce highly reversible electrochemical intercalation process and fast kinetics. The resultant KNHCF cathode demonstrates reversible capacity of 57.0 mAh·g−1, high operating voltage of 3.74 V, outstanding voltage stability with no decay, good cycling stability (87.34%) after 1000 cycles and long-term lifetime over 8000 cycles with capacity fading rate of 0.0052% per cycle. A solid solution mechanism with zero-strain, where one-electron shuttle relied on C-coordinated Fe/Fe couple, plays an important role for K-ions intercalation/deintercalation. A 3.34 V full cell assembled with graphite anode delivers a high energy density of 142.6 Wh·kg−1 with the cpacity retention of 88.5% after 100 cycles, and ultra-long life-span over 5000 cycles can be achieved.

Original languageEnglish
Pages (from-to)120-127
Number of pages8
JournalEnergy Storage Materials
Volume22
DOIs
StatePublished - Nov 2019
Externally publishedYes

Keywords

  • Cathode materal
  • Potassium nickel hexacyanoferrate
  • Potassium-ion battery
  • Ultralong life
  • Zero-strain

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