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

Abstract

Two-dimensional anode materials are commonly optimized through planar lattice engineering or surface corrugation to enhance ion accessibility and mechanical stability. Here, we report a pore-state engineering strategy in bowl-shaped phosphorus–carbon (P–C) monolayers, exemplified by P₃C₇ and its pore-filled derivative P₃C₈, which share the same framework but differ in pore topology. Both monolayers exhibit metallic conductivity and thermodynamic stability, yet the open versus filled pore structures induce markedly distinct local electrostatic environments and bonding topologies. In P₃C₇, large intrinsic pores enable delocalized interactions between P lone-pair electrons and C p_z orbitals, facilitating nearly isotropic low-barrier K-ion migration (0.23 eV) along multiple pathways and high theoretical capacity (1515.2 mAh g⁻¹). P₃C₈, by contrast, exhibits localized electron density at the filled pore, yielding anisotropic diffusion with fewer viable pathways and slightly higher barriers (0.28 eV), and moderate capacity (1277.1 mAh g⁻¹). The bowl-shaped geometry of both structures effectively buffers lattice strain during ion insertion, with P₃C₇ benefiting from large voids and P₃C₈ from enhanced lattice rigidity. These findings indicate that ion-storage behavior in bowl-shaped 2D materials is primarily regulated by pore-state-induced reconstruction of the local electrostatic landscape, rather than simply by the magnitude of charge transfer, highlighting pore-state engineering as an effective design strategy for high-performance potassium-ion anodes.