Dual Engineering of Electronic and Mechanical Properties via Heterocontact–Curvature Interfaces for Ultra-Stable K-Ion Storage

Despite the demonstrated efficacy of contact curvature interfaces in enhancing the electrochemical performance of graphitic carbon materials for potassium-ion batteries, long-term cycling stability remains a critical challenge due to structural degradation caused by repeated volume expansion/contraction. Herein, we propose a structural design by introducing a 3–5 nm ultrathin amorphous carbon buffer layer at the contact curvature interface of graphitic carbon domains, constructing an amorphous/graphitic carbon heterocontact-curvature interface (AG-CI). Through systematic density functional theory calculations, we demonstrate that the AG-CI architecture can significantly enhance the electronic states near the Fermi level, which not only facilitates rapid electron transport but also strengthens reversible K+ adsorption at the contact curvature interface. Concurrently, the amorphous carbon buffer layer serves as a mechanical stabilizer, effectively accommodating volume variation during charge–discharge processes, alleviating structural stress, and enabling cycling performance. This synergistic optimization of electronic conductivity and mechanical robustness leads to exceptional electrochemical performance, including rate performance (154.9 mAh g–1 at 4 A g–1) and cycling durability (nearly 100% capacity retention per cycle). Our dual engineering strategy, which simultaneously addresses electronic and mechanical challenges, provides a versatile platform for the development of high-performance carbon-based anodes in next-generation batteries.