In this paper, the structure evolution of cerium cobaltohexanoate (Ce[Co(CN)₆], Ce-Co Prussian blue analog (PBA)) has been realized by solvent catalysis at room temperature. The hexagonal bipyramidal microcrystals of Ce-Co PBA can be gradually transformed into dendrites by different proportions of ethanol (EtOH) and water. At the same time, the porous dendrites CeO₂/Co@carbon nanotub (CNT) with oxygen-rich vacancies (OVs) can be obtained by annealing Ce-Co PBA at 700 °C. The microstructure study shows that carbon nanotubes will be catalyzed after annealing at high temperature, and the cobalt metal particles encapsulated in carbon nanotubes will be anchored in the matrix, regulating the impedance matching and multi-polarization suppression of the material, and its unique structure, vacancies, and strong interface effect make the material exhibit excellent electromagnetic wave (EMW) absorption performance. When the matching thickness is 2.5 mm, the minimum reflection loss (RL_min) of the composite is −51.68 dB, and the effective absorption bandwidth (RL < −10 dB) is 7.76 GHz. These results show that the prepared CeO₂/Co@CNT composite has excellent EMW absorption properties. It is expected to be a candidate material for EMW absorption.

The accelerated arriving of 5G era has brought a new round of intelligent transformation which will completely emancipate smart terminal devices. While the subsequent deleterious effect of electromagnetic wave on electronic devices is increasingly serious, driving the growth of next-generation electromagnetic wave absorbents. As a tactful combination of components and structures, three-dimensional (3D) macroscopic absorbents with fascinating synergy afford exceptional electromagnetic wave absorption, and tremendous efforts have been devoted to this investigation. However, in terms of macroscopic absorbents and their synergistic effect, few reviews are proposed to comb the latest achievements and detailed synergy. This review article focuses on the synergistic effect of macro-architectured absorbents mainly including structure-induced synergy, structure-components synergy, and multiple-components induced synergy. And then the potential construction principles and strategies of macroscopic absorbents are combed. Significantly, the key information for structures and components manipulation including nano-micro design and components regulation is further dissected by critically selected cutting-edge 3D macroscopic absorbents. Moreover, a brief summary of multifunctional electromagnetic wave absorbents (EWAs)-based macroscopic structures is presented. Finally, the development prospects and challenges of these materials are discussed.

The weak dielectric properties and the lack of magnetic loss of manganese-based absorbers are obstructed as the new generation of electromagnetic wave absorption (EMA) materials applying in microelectronic devices. Herein, the sulfuration and subsequent compounding strategies have been employed to enhance the EMA performance of multi-shell nanosphere-shaped Mn₂O₃ materials. With the narrow bandgap, the as-obtained MnS possesses reinforced electrical conductivity, which is conducive to conductivity loss. More importantly, the presence of potential difference between different phases will form space charge region at the heterogeneous interface, thus favoring interfacial polarization. Additionally, the improvement of magnetic loss is attributed to the presence of Co₃O₄ nanoparticles. Consequently, the composites present enhanced EMA performance than original Mn₂O₃. Specifically, the minimum reflection loss of as-prepared composites is −51.4 dB at the thickness of 1.8 mm and the broad effective absorption bandwidth reaches 6.2 GHz at 1.9 mm. The low matching thickness and high absorption efficiency in this work can provide a convincing reference when designing distinguished manganese-based absorbers.