Local Charge Engineering Through Anion–Cation Co-modulation for Multifunctional Programmable Electromagnetic Wave Attenuation

Electromagnetic wave absorption (EMWA) materials with tunable responses are critically important for operation in complex electromagnetic environments. In this study, a novel dual-ion co-modulation strategy is introduced to overcome the limited controllability of conventional EMWA materials. By employing a coordination-mediated gelation phase transformation approach, a series of transition metal sulfide/sulfur–nitrogen co-doped carbon (M_xS_y/SNC, M = Fe, Co, Ni, or Cu) aerogels are successfully fabricated. First-principles calculations demonstrate that N,S co-doping tunes the electronic structure of the carbon matrix, enhancing local charge imbalance and promoting dipole polarization, which significantly broadens the EMWA band. At 1.65 mm, the effective absorption bandwidth almost covers the entire Ku band. Furthermore, cation-induced modulation of the electronic configuration enables precise tuning of the built-in electric field and dielectric response, resulting in customizable absorption peaks and bandwidths. All samples achieve a minimum reflection loss (RL_min) below −60 dB, with the RL_min peak frequency shifting from 17.44 GHz to 11.6, 9.84, and 5.12 GHz depending on the metal ion. Finally, a low-frequency antenna and a one-to-two power divider are constructed, demonstrating strong application potential in the communications field. This study provides a new pathway for designing high-performance, programmable EMWA systems and multifunctional materials.