A fluoroxalate cathode material for potassium-ion batteries with ultra-long cyclability

Bifa Ji, Wenjiao Yao, Yongping Zheng, Pinit Kidkhunthod, Xiaolong Zhou, Sarayut Tunmee, Suchinda Sattayaporn, Hui-Ming Cheng, Haiyan He, Yongbing Tang
2020 Nature Communications  
Potassium-ion batteries are a compelling technology for large scale energy storage due to their low-cost and good rate performance. However, the development of potassium-ion batteries remains in its infancy, mainly hindered by the lack of suitable cathode materials. Here we show that a previously known frustrated magnet, KFeC2O4F, could serve as a stable cathode for potassium ion storage, delivering a discharge capacity of ~112 mAh g-1 at 0.2 A g-1 and 94% capacity retention after 2000 cycles.
more » ... after 2000 cycles. The unprecedented cycling stability is attributed to the rigid framework and the presence of three channels that allow for minimized volume fluctuation when Fe2+/Fe3+ redox reaction occurs. Further, pairing this KFeC2O4F cathode with a soft carbon anode yields a potassium-ion full cell with an energy density of ~235 Wh kg-1, impressive rate performance and negligible capacity decay within 200 cycles. This work sheds light on the development of low-cost and high-performance K-based energy storage devices.
doi:10.1038/s41467-020-15044-y pmid:32144250 fatcat:wrqawgc5mvfebpdlze76fvewzi