Phosphorus‐Driven Heteroatom Doping in Mesoporous Carbon Hollow Platelets Enables Efficient Electromagnetic Wave Absorption

Phosphorus (P) doping has emerged as an effective strategy for tailoring the electromagnetic properties of carbon‐based materials by modulating defect density, dielectric polarization, and electrical conductivity. Herein, a series of porous phosphorus‐doped carbon hollow platelets (PCHPs) with well‐defined biconcave morphologies are synthesized through a template‐assisted polymerization strategy followed by hydrothermal phosphorylation and calcination. By systematically adjusting the phosphorus content and calcination temperature, we achieved precise control is achieved over the defect concentration, graphitization degree, and electrical conductivity. Theoretical calculations combined with experimental characterizations revealed that P atoms induce local charge redistribution and form P─C/P─O/P═O bonds, generating abundant dipole centers and enhancing polarization relaxation. Notably, the PCHP‐750–0.2 specimen demonstrated optimal electromagnetic waves absorption performance, achieving a minimum reflection loss of −34.05 dB at 1.8 mm and an effective absorption bandwidth of 5.08 GHz at 2.0 mm. The enhanced absorption arisen from the synergistic effects of defect‐induced polarization, moderate conductivity for impedance matching, and multi‐scattering pathways enabled by the hollow platelet structure. Furthermore, CST simulations confirmed superior radar cross‐section reduction capability. This work not only proposes a versatile route for engineering phosphorus‐doped carbon architectures, but also provides in‐depth insight into the structure‐property‐performance relationships that govern high‐efficiency electromagnetic waves attenuation.