Enhancing Potassium Storage Performance in VO2/V2O3@C Nanosheets by Synergistic Effect of Oxygen Vacancy and C‐O‐V Bond

Abstract The potassium‐ion battery (PIB) is regarded as a promising energy storage system to replace lithium‐ion battery, while the sluggish kinetics and large K + size result in inferior rate performance and poor cycle stability, impeding its extensive development. Here, a carbon coated VO 2 /V 2 O 3 nanoparticles (VO 2 /V 2 O 3 @C) was prepared by simple reflux and pyrolysis process with polyaniline as the carbon source. The C−O−V bond and the oxygen vacancy within VO 2 /V 2 O 3 @C can not only accelerate the charge transfer between carbon and VO 2 /V 2 O 3 nanoparticles, but also increase the active sites. Therefore, VO 2 /V 2 O 3 @C as an anode for PIB exhibits an excellent rate (78 mAh g −1 at 0.5 A g −1 ) and long‐cycling performance (147.9 mAh g −1 at 50 mA g −1 after 1000 cycles), and the full cell PIB shows high power density and energy density as well. This work provides a pathway to design other high‐performance anodes for PIBs.