Low-Cost K4 Fe(CN)6 as a High-Voltage Cathode for Potassium-Ion Batteries

Yuhou Pei; Chaonan Mu; Haixia Li; Fujun Li; Jun Chen

doi:10.1002/cssc.201800057

Low-Cost K₄ Fe(CN)₆ as a High-Voltage Cathode for Potassium-Ion Batteries

ChemSusChem. 2018 Apr 25;11(8):1285-1289. doi: 10.1002/cssc.201800057. Epub 2018 Mar 23.

Authors

Yuhou Pei¹, Chaonan Mu¹, Haixia Li¹, Fujun Li¹, Jun Chen^{1

2}

Affiliations

¹ Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin, 300071, P. R. China.
² Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300071, P. R. China.

PMID: 29498226
DOI: 10.1002/cssc.201800057

Abstract

Potassium-ion batteries (KIBs) are of interest for large-scale electrical energy storage, owing to the abundance of K resources and potential high energy density. Low-cost cathodes with high performance are crucial for KIBs. Herein, K₄ Fe(CN)₆ is shown to be a low-cost and high-voltage cathode for KIBs. It can deliver a high voltage of approximately 3.6 V and a discharge capacity of 65.5 mAh g^-1 with a lifespan of 400 cycles of discharge and charge. This is attributed to the strong σ bonds between C atoms and Fe and to the reduced particle size and good contact with conductive carbon brought about by ball milling, which benefit both the K⁺ ion and the electronic conduction. The [Fe(CN)₆ ]^3-/4- redox couple is found to be responsible for charge compensation upon reversible extraction/insertion of K⁺ from/into K₄ Fe(CN)₆ . The high voltage and stability of K₄ Fe(CN)₆ will make it a promising low-cost cathode for KIBs and encourage more investigations into high-performance cathode materials.

Keywords: batteries; electrode materials; energy density; polarization; potassium.