Nitrogen doping is an effective strategy to improve potassium ion storage of carbon electrodes via the creation of adsorption sites. However, various undesired defects are often uncontrollably generated during the doping process, limiting doping effect on capacity enhancement and deteriorating the electric conductivity. Herein, boron element is additionally introduced to construct 3D interconnected B, N co‐doped carbon nanosheets to remedy these adverse effects. This work demonstrates that boron incorporation preferentially converts pyrrolic N species into BN sites with lower adsorption energy barrier, further enhancing the capacity of B, N co‐doped carbon. Meanwhile, the electric conductivity is modulated via the conjugation effect between the electron‐rich N and electron‐deficient B, accelerating the charge‐transfer kinetics of potassium ions. The optimized samples deliver a high specific capacity, high rate capability, and long‐term cyclic stability (532.1 mAh g−1 at 0.05 A g−1, 162.6 mAh g−1 at 2 A g−1 over 8000 cycles). Furthermore, hybrid capacitors using the B, N co‐doped carbon anode deliver a high energy and power density with excellent cycle life. This study demonstrates a promising approach using BN sites for adsorptive capacity and electric conductivity enhancement in carbon materials for electrochemical energy storage applications.

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 VO2/V2O3 nanoparticles (VO2/V2O3@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 VO2/V2O3@C can not only accelerate the charge transfer between carbon and VO2/V2O3 nanoparticles, but also increase the active sites. Therefore, VO2/V2O3@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.

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