Long Xia

Perovskite oxides with excellent structural compatibility and tunable electronic structures are ideal high-performance electromagnetic wave absorbers. Conventionally ion-modified LaMnO3 perovskites usually exhibit a single loss modulation mode. Few studies have discussed the shift rule of effective absorption bands under different doping ratios. Meanwhile, systematic research combining low-valent metal doping with microstructure regulation is still scarce. Herein, a series of nanoscale LaMn1−xNixO3 (0 ≤ x ≤ 0.25) perovskites were synthesized via the sol−gel method. Non-equivalent Ni2+ doping induces multivalent Mn coexistence, regulates oxygen vacancies, and triggers lattice distortion to jointly optimize conductive loss and polarization loss. Ni doping drives the formation of an interconnected network architecture composed of particle-assembled rod-like structures, which boosts electromagnetic multi-scattering and interfacial polarization. The optimized sample delivers excellent microwave absorption performance with a minimum reflection loss of −54.52 dB and an effective absorption bandwidth of 4.7 GHz, achieving frequency-tunable absorption over the C, X, and Ku bands.

The high-efficiency absorption of low-frequency electromagnetic waves remains a key bottleneck in electromagnetic protection. Conventional carbon/magnetic fillers are limited by excessively large skin depth, limited magnetic response, and oxidation-induced parameter drift at elevated temperatures, making it difficult to simultaneously satisfy low-frequency absorption and high-temperature durability. This work proposes a charge imbalance–driven Jahn–Teller strategy and fabricates single-phase La_1–xCa_xMnO₃ perovskites via a sol–gel method. The Ca²⁺/La³⁺ ionic-size mismatch induces MnO₆ octahedral distortion and is accompanied by Mn³⁺/Mn⁴⁺ redistribution and oxygen-vacancy evolution, which strengthens polarization-related dielectric loss and enables coordinated improvement in attenuation capability and impedance matching. Consequently, the dominant dielectric relaxation/absorption response is shifted toward lower frequencies. The optimized sample achieves a minimum reflection loss of −40.46 dB at 4.72 GHz with an effective absorption bandwidth of 4.40 GHz. Far-field radar cross-section simulations further provide evidence of scattering suppression, with a maximum echo reduction of 30.7 dB·m² for a metal plate. This strategy is extendable to perovskite oxide systems and offers a generalizable design guideline for thermally robust low-frequency absorbing coatings.

High‐performance electromagnetic wave (EMW) absorbers with environmental adaptability are essential for advanced maritime stealth and electromagnetic protection. Herein, we design a synergistic absorber integrating Fe clusters (Fe _AC ) and single atoms (Fe _SA ) to tackle the issue of EMW attenuation under high-salinity and humidity marine conditions. First-principles calculations and experiments reveal that Fe _AC and Fe _SA anchored on a π ‐conjugated carbon support form a delocalized electronic space that enables long-range electronic interactions and multicenter synergistic coupling. This electronic synergy markedly strengthens conduction loss and dipolar polarization, delivering a minimum reflection loss of − 68.78 dB and an effective absorption bandwidth of 6.00 GHz at a low loading of 6 wt%. Notably, Fe _AC exhibits a thermodynamically preferred adsorption toward Cl ⁻ , generating locally enriched negative‐charge regions that mitigate direct ionic attack on atomically dispersed Fe _SA sites and thereby suppress corrosion-induced performance degradation. In addition, the absorber film demonstrates mechanical flexibility and thermal insulation, highlighting its potential for durable and high‐efficiency maritime EMW protection applications.

Escalating electromagnetic pollution and advanced stealth technologies require next-generation microwave absorbers that combine broadband response, strong attenuation, and lightweight characteristics with high-temperature stability. In this work, a vacancy-mediated strategy is proposed to tailor electromagnetic losses in Cr-doped lanthanum manganite perovskites (LaMn_1-xCr_xO₃) synthesized by a sol–gel method. The cooperative modulation between Mn-site cation vacancies and oxygen vacancies enables a well-balanced contribution of polarization loss and conduction loss, resulting in excellent absorption performance. Specifically, LaMn_0.85Cr_0.15O₃ achieves a remarkable minimum reflection loss of -75.37 dB and an effective absorption bandwidth of 6.0 GHz at a thickness of only 2.8 mm. Structural and spectroscopic analyses reveal that Cr³⁺ substitution induces Mn vacancies and modulates oxygen vacancy concentrations, thereby generating defect dipoles and facilitating carrier migration. Density functional theory calculations further elucidate the role of Cr-induced defect states in enhancing conduction and polarization losses. This vacancy-engineered approach not only establishes a new paradigm for designing high-efficiency perovskite-based microwave absorbers but also offers significant potential for high-temperature electromagnetic compatibility applications.

The rapid advancement of wireless communication and the increasing demand for electromagnetic stealth have intensified the need for high-performance electromagnetic wave absorbing materials. This work introduces an innovative bio-inspired strategy for synthesizing silicon carbide nanostructures anchored on biomass-derived carbon from fig skin via a high-temperature vapor-solid deposition method. By precisely modulating the silicon-to-carbon ratio, we developed various silicon carbide morphologies—including spherical, coral-like, and linear architectures—of which the coral-like configuration (Silicon-Carbide-3 (SC-3)) exhibited remarkable electromagnetic wave absorption capabilities. Specifically, SC-3 achieved a minimum reflection loss of –51.27 dB at 14.1 GHz and an effective absorption bandwidth of 4.64 GHz. The enhanced absorption is attributed to the synergistic effects of interface polarization, dipole polarization, and multiple internal reflections fostered by the unique porous structure. These findings underscore the versatility of biomass-derived carbon in tailoring advanced nanostructures and pave the way for developing next-generation electromagnetic absorbers with optimized impedance matching and broadband capabilities.