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Hao et al. Soft Sci. 2025, 5, 39 https://dx.doi.org/10.20517/ss.2025.48 Page 13 of 25

substantial Joule heating, effectively dissipating incident energy. Crucially, the spatial isolation of these units
mitigates macroscopic conductivity-induced reflection, allowing enhanced wave penetration and multi-path
absorption. This architecture-temperature synergy results in stable performance across broad temperature
ranges, outperforming conventional continuous networks prone to thermal conductivity fluctuations. For
instance, Shao et al. employed a wet-spinning technique to fabricate nanofiber microspheres, which feature
[99]
a hierarchical local conductive network . When integrated with paraffin wax, the resulting absorbing
composite achieved a remarkable minimum RL of -72.34 dB at an ultralow filler loading of just 1.2 wt.%,
accompanied by a broad absorption bandwidth of 8.12 GHz [Figure 4A]. Meanwhile, Jiang et al. pioneered
the discovery that MSMCs exhibit unique advantages in high-temperature microwave absorption . By
[79]
constructing localized conductive networks within RGO@carbon microspheres [Figure 4B], the
metacomposites with only 3.0 wt.% filler loading demonstrated an effective absorption bandwidth (RL < -10
dB) covering the entire X-band across temperatures from 298 to 473 K, with a minimum RL of -57 dB at 433
K. Due to the decoupling of conductivity and impedance matching achieved by the functional unit, it
exhibited temperature insensitive electromagnetic performance at high temperatures.

Graphene nanosheets (GNs) exhibit a large specific surface area and exceptional electrical conductivity;
however, their pronounced impedance mismatch arising from excessive conductivity limits microwave
absorption applications. The advent of MSMCs has enabled GNs to achieve unique advantages in this field.
Fang et al. fabricated GNs/PES composites via a simple solution-blending strategy combined with solvent
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evaporation . During the synthesis process, the GNs spontaneously self-assembled into mesoscale
microcluster architectures that served as functional units. As illustrated in Figure 4C, the design of
functional unit significantly optimized impedance matching and loss characteristics of the GNs/PES
electromagnetic composites, which demonstrated stable absorption bandwidth and strong absorption peaks
(RL < -25 dB) across 293-453 K. More recently, Zhang et al. developed MSMCs using RGO microspheres as
functional units . Figure 4D revealed negligible fluctuations in the real/imaginary parts of the dielectric
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constant over broad temperatures, with RGO metacomposites maintaining stable microwave absorption
performance (RL < -10 dB) from 293 to 453 K.

Apart from the conductive loss, the polarization loss represents a critical component of dielectric loss.
Thermally induced polarization loss decreases with increasing temperature, enabling synergistic
compensation for the concurrent rise in conductive loss. Thus, enhancing polarization loss within
mesoscopic functional units plays a pivotal role in optimizing microwave absorption performance.
Predominant polarization mechanisms in such units encompass dipole polarization (e.g., from functional
groups) and interfacial polarization (e.g., Maxwell-Wagner relaxation at filler-matrix interfaces). Li et al.
fabricated MXene@graphene oxide hybrid aerogel microspheres via rapid freezing-assisted
electrospinning . As can be seen in Figure 5A, the microspheres exhibited a rich conductive network
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internally, and the formation of numerous heterojunctions between MXene and GO significantly enhanced
the interfacial polarization of the composite material. The stacking defects and surface functional groups
present in both dielectric materials further enhance the dipole polarization. The presence of multiple
semicircles in the Cole-Cole curve indicated that MXene@graphene oxide hybrid aerogel microspheres
exhibited multiple dielectric relaxations. Constructing core-shell architecture has emerged as a pivotal
design strategy for boosting interfacial polarization. Zhi et al. employed coaxial electrospinning to fabricate
aerogel microspheres with core-shell double-layer structures . Figure 5B clearly revealed the core-shell
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morphology of carbon/graphene microspheres, and Cole-Cole plot analysis confirmed that polarization
losses constitute a significant fraction of total dielectric losses, alongside conductive dissipation. Simulation
results demonstrate that compared to single-layer graphene microspheres, the core-shell carbon/graphene
microspheres exhibited a higher volume loss density, underscoring their superior attenuation capability.