Bimetallic Oxide/Carbon Fiber Heterodimensional Structure Toward Dual Electromagnetic Attenuation Functions

ABSTRACT Achieving concurrent high‐performance electromagnetic absorption and electromagnetic interference (EMI) shielding within a single material system at a fixed filler loading remains a significant challenge. Here, a heterodimensional structural strategy for CuCo 2 O 4 @C is proposed to reconcile dielectric and magnetic responses. The dielectric relaxation loss is dominated by Jahn–Teller distortion, coupled with contributions from carbon defects and CuCo 2 O 4 @C interfaces. The magnetic response is primarily driven by Metal–Oxygen–Metal (M–O–M) superexchange interactions that modulate the magnetic precession, complemented by the eddy current effect. The prepared CuCo 2 O 4 @C composite successfully integrates the dual functions of electromagnetic absorption and EMI shielding. The total functional bandwidth of the CuCo 2 O 4 @C composite is 4.24 GHz at a thickness of 1.8 mm, including an effective absorption bandwidth of 2.72 GHz and an EMI shielding bandwidth of 1.52 GHz. When its thickness increased to 2.6 mm, the total functional bandwidth was extended to 6.48 GHz (0.56 GHz for absorption and 5.92 GHz for shielding). This work offers a promising route for miniaturization and functional integration of electromagnetic attenuating materials and devices.