Rational Design of Porous Nodal-Line Semimetallic Carbon for K-Ion Battery Anode Materials

The potassium-ion battery (KIB), as one of the most promising alternatives to the lithium-ion battery (LIB), has recently received considerable attention. One of the challenges in KIBs is the design and synthesis of high-performance anode materials with high capacity, high rate performance, and good cycling stability. Here, on the basis of first-principles calculations, we propose a three-dimensional (3D) porous nodal-line semimetal carbon allotrope, named BDL-14, consisting of benzene rings incorporated into the diamond lattice, as a potential candidate. With low mass density (1.41 g/cm³), ordered channels, high carrier velocity (0.83 × 10⁶ m/s), high specific capacity (478.23 mAh/g), very low energy barriers (0.05-0.08 eV) for K-ion diffusion, and a small volume expansion (7.03%) during charging and discharging processes, BDL-14 can surpass the properties of anodes currently being considered.