Pore-state engineering in bowl-shaped two-dimensional phosphorus–carbon monolayers toward high-performance potassium-ion anodes

P ₃ C ₇ and P ₃ C ₈ monolayers share the identical framework but differ in pore topology. P ₃ C ₇ with large pores presents lower diffusion barrier, while both benefit from curvature to exhibit low open-circuit voltage and exceptional K-storage capacity.