Accelerated Carrier Kinetics in Hollow Cubic Mott–Schottky CoFe@carbon Composites for High‐Efficiency Broadband Electromagnetic Wave Absorption

ABSTRACT The ever‐growing electromagnetic pollution from modern technology calls for high‐performance wave‐absorbing materials that master the delicate balance between impedance matching and attenuation capability—a balance missed by conventional heterojunctions due to their sluggish carrier kinetics and performance trade‐offs. Herein, we propose a multi‐scale design strategy integrating Mott–Schottky heterojunctions within a hollow cubic CoFe@carbon architecture. Work function disparity between Co _0.7 Fe _0.3 and carbon drives the formation of a built‐in electric field, accelerating charge relaxation and enabling significant spatial charge migration. The directional movement of these charges under high‐frequency electromagnetic fields effectively attenuates incident energy—critical for broadening the absorption bandwidth—while the hollow cubic morphology optimally tunes the impedance matching, essential for achieving a wide effective absorption band. This synergy between interfacial electric fields and structural features successfully breaks the conventional attenuation‐matching compromise. Consequently, the optimized material achieves a remarkable ultra‐wide EAB of 7.76 GHz at 2.5 mm and RL _min of −43.22 dB. Theoretical calculations confirm that the remarkable electromagnetic wave absorption performance originates from a synergistic effect, revealing the critical roles of enhanced interface polarization driven by the Mott–Schottky effect, well‐optimized conductive networks, and excellent impedance matching endowed by the unique hollow cubic structure. This strategy offers profound insights into addressing the fundamental limitations of traditional absorbers and paves a promising way for developing next‐generation high‐performance EM functional materials.