Charging‐State Behavior of N/O/F‐Doped Carbon Anodes for K‐Ion Batteries

Potassium‐ion batteries (KIBs) are emerging as cost‐effective alternatives to Li‐ and Na‐ion systems, yet their performance is governed by adsorption‐driven K storage on carbon anodes and the associated charging‐state transition from K ⁺ to neutral K. Here, density functional theory was used to elucidate the charging‐state potassium storage on heteroatom‐doped graphene, systematically comparing N, O, and F single doping and their multi‐doped combinations (N/O, O/F, N/F, and N/O/F). By integrating molecular electrostatic potential mapping, K ⁺ /K adsorption energetics, adsorption‐derived operating voltages, optimized adsorption geometries, and HOMO–LUMO characteristics, we established a unified framework linking electrostatic modulation to thermodynamic balance and structural accommodation. N doping produced a locally electron‐enriched potential landscape that strengthens K ⁺ anchoring, whereas O doping most effectively reduced the energetic mismatch between K ⁺ adsorption and neutral K storage, thereby moderating the K ⁺ → K conversion penalty. F doping induced pronounced nonplanarity and a compliant adsorption pocket that enhances out‐of‐plane accommodation of both K ⁺ and K. In multi‐doped systems, N/O and O/F exhibited complementary role sharing that stabilizes adsorption and K ⁺ → K conversion, while N/F revealed a trade‐off without O. Notably, N/O/F co‐doping optimized electrostatic driving force, conversion energetics, and structural compliance, providing practical design rules for advanced carbon anodes in KIBs.