Dual-functional core–shell composites: Integrated microwave absorption and thermal management properties

• Co–C@SiO2 achieves ultra-strong microwave absorption with RLmin of -51.9 dB and EAB of 5.36 GHz at 2.0 mm thickness. • The SiO2 protective shell prevents structural collapse and introduces abundant heterogeneous interfaces, enhancing interfacial polarization and dielectric loss. • Both Co–C@SiO2 and Zn–C@SiO2 composites exhibit rapid thermal response, demonstrating dual functionality for microwave absorption and thermal management. • Pyrolysis of ZIF@SiO2 precursors yields hollow carbon frameworks with uniformly dispersed Co/Zn nanoparticles, optimizing impedance matching and loss mechanisms.