Biomass‐Derived Carbon with Heavy Doping for Anode of Potassium Ion Batteries

ABSTRACT The potassium‐ion battery (PIB) is anticipated to be a cost‐effective candidate for large‐scale energy storage for the green power grid. For PIB anodes, carbon is promising owing to its conductivity and abundance. Yet, the insufficient cycle life and rate performance of the carbon anode remain the bottleneck limiting PIBs, stemming from the mismatch between the narrower graphitic interlayer spacing and the larger radius of potassium. Herein, a large number of heteroatoms (18.2 at%) are incorporated into a biomass‐derived carbon. The synthesized carbon material is thus endowed with improved interlayer spacing as well as active sites and mesoporous structures. These attributes collectively contribute to outstanding cycle life (18 000 cycles) and rate capability (260 mAh g −1 at 20 A g −1 ), making it a promising candidate for PIBs for grid‐oriented energy storage.