Dual‐strategy Design of AlPO ₄ /Co ₂ P/Carbon Composites with Enhanced Microwave Absorption and Thermal Management: Element Doping and Phase Transition Engineering

Abstract Modern electronic devices face significant challenges from electromagnetic interference and heat accumulation, necessitating advanced materials that integrate efficient electromagnetic wave (EMW) absorption with effective thermal management. However, it remains a challenge to balance wave absorption and thermal conductivity of materials. This work introduces phosphorus (P)‐doped AlPO ₄ /Co ₂ P/P‐C (ACPC) composites, featuring a porous structure and multiphase system, fabricated by controlling the migration of P atoms in CoAl‐LDHs/gelatin via freeze‐drying and high‐temperature carbonization. The composites exhibit a remarkable reflection loss (RL) of −72.2 dB and an effective absorption bandwidth (EAB) of 8.54 GHz. The Radar Cross Section (RCS) simulations indicate a substantial stealth effect, complemented by a heat conductivity of 0.739 W(mK) ⁻¹ . The exceptional performance is attributed to several key factors: P‐doping modifies charge distribution and enables d‐p hybrid orbitals between Co and P atoms, thereby enhancing conductivity and polarization loss. Chemical phase transitions induce defects and grain boundaries, significantly enhancing magnetic anisotropy and thereby boosting magnetic loss. Additionally, the porous, multiphase structure promotes multiple EMW reflections and scattering, while interfacial differences in electromagnetic parameters within the composites optimize impedance matching. This research presents a novel strategy to develop integrated materials with both wave absorption and thermal management.