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Wang et al. Soft Sci. 2026, 6, 8 Page 7 of 28

(c) The dielectric loss effects could be improved by the unique microstructure of the aerogel. The porous
structure possesses abundant carbon-air interface areas, where a significant amount of charge accumulates
on both sides of the heterointerface, promoting interfacial polarization loss behaviors. Besides, the 3D
interconnected conductive network skeleton of the aerogel could effectively support the transport of the
electrical carriers, thereby enhancing the conduction loss.

MICROWAVE ABSORPTION PERFORMANCE OF CARBON-BASED AEROGEL BY DIFFERENT
SYNTHESIS STRATEGIES
Hard-templates methods
Natural porous template
Research on natural materials has attracted widespread attention for bio-derived carbon-based microwave
absorption aerogels, owing to their inherent biological tissue and porous structures, as well as eco-friendly
properties such as abundant resources, diverse forms, and low cost. Many natural biomasses possess unique
biological tissue structures, which can be well preserved during high-temperature pyrolysis, thus providing a
facile and convenient method to construct 3D porous carbon aerogels . Typically, natural woods with
[71]
cellular parenchyma tissues and porous bundles are well-recognized precursors for carbon-based
microwave-absorbing aerogels, but they exhibit unsatisfactory microwave-absorbing performance due to
relying solely on the dielectric loss mechanism. Incorporating magnetic components is widely adopted to
tailor the EM response characteristics and the corresponding MA performance effectively .
[72]
Zhao et al. prepared magnetic nickel-decorated carbon aerogel composites via a direct impregnation
approach, using NiCl and poplar wood as raw materials . The wood matrix was immersed in a hydrated
[73]
2
nickel chloride solution and subjected to vacuum impregnation. Following complete drying,
high-temperature carbonization was performed at different temperatures to prepare target composites,
which directly influenced the microwave absorption characteristics. When the carbonization temperature
was set to 700 °C, the minimum RL value reached -60.4 dB at a thickness of 2.93 mm. Furthermore, the EAB
was greatly extended to 7.3 GHz at a thickness of 2.63 mm. To address weak interfacial bonding and uneven
component distribution from the direct immersion method, Gou et al. in situ grew bimetallic organic
frameworks on balsa wood via co-precipitation, followed by high-temperature annealing under a protective
atmosphere to obtain CoNi-modified wood-derived carbon composites . When the pyrolysis temperature
[74]
was 700 °C, the optimal RL value reached -25.96 dB at 17.98 GHz with a thickness of 1.8 mm.

In addition to the co-precipitation method, hydrothermal and solvothermal methods are also considered
feasible approaches for constructing bio-derived porous MAM. Cui et al. successfully prepared
high-performance magnetic component-loaded porous carbon composites using wood as raw material
through hydrothermal and carbonization processes [75] . The uniform distribution of magnetic
nanocomposites maintained the porous microstructure of the carbon framework and contributed to multiple
EM dissipation mechanisms, thereby achieving outstanding microwave absorption performance with the RL
of -62.235 dB at a thickness of just 2.42 mm. Cui et al. employed a porous structure engineering strategy to
fabricate a high-performance Co/niobium carbide (Nb CT )/carbon aerogel composite material .
[76]
2
x
Compared with bamboo cellulose carbon aerogels, the introduction of conductive Nb CT and the magnetic
x
2
Co component could effectively improve the impedance matching behaviors of the corresponding
Co/Nb CT /carbon aerogel. Besides, the 3D interconnected network heterostructure not only promoted
2
x
conduction loss but also facilitated the multi-reflection and multi-scattering effects, thereby exhibiting a
remarkable RL value of -60.25 dB at a thickness of 1.67 mm and a low density of 54.03 mg·cm . Furthermore,
-3
the Radar Cross Section (RCS) simulation results indicate the aerogel’s effectiveness in reducing its
detectability.