Defect-free potassium manganese hexacyanoferrate cathode material for high-performance potassium-ion batteries

Potassium-ion batteries (KIBs) are promising electrochemical energy storage systems because of their low cost and high energy density. However, practical exploitation of KIBs is hampered by the lack of high-performance cathode materials. Here we report a potassium manganese hexacyanoferrate (K2Mn[Fe(CN)(6)]) material, with a negligible content of defects and water, for efficient high-voltage K-ion storage. When tested in combination with a K metal anode, the K2Mn[Fe(CN)(6)]-based electrode enables a cell specific energy of 609.7 Wh kg(-1) and 80% capacity retention after 7800 cycles. Moreover, a K-ion full-cell consisting of graphite and K2Mn[Fe(CN)(6)] as anode and cathode active materials, respectively, demonstrates a specific energy of 331.5 Wh kg(-1), remarkable rate capability, and negligible capacity decay for 300 cycles. The remarkable electrochemical energy storage performances of the K2Mn[Fe(CN)(6)] material are attributed to its stable frameworks that benefit from the defect-free structure. Potassium-ion battery is a promising candidate for post-Li-ion energy storage but the lack of cathode materials hinders practical exploitation. Here the authors investigate defect-free potassium manganese hexacyanoferrate as cathode active material for high energy and long lifespan K-based cells.

Automated summary

The potassium-ion battery shows great potential as a post-Li-ion energy storage system, but the lack of high-performance cathode materials has been a barrier to practical applications. In this study, defect-free potassium manganese hexacyanoferrate is investigated as a cathode active material for high-energy and long-lasting potassium-based cells.