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Page 2 of 16 Sun et al. Soft Sci. 2025, 5, 35 https://dx.doi.org/10.20517/ss.2025.21

INTRODUCTION
Recently, the progress of modern electronic and wireless communication technologies is generating
excellent electromagnetic (EM) radiation, resulting in significant pollution that disrupts the functionality of
electronic systems and poses substantial risks to human health and ecological stability . As a result, EM
[1-6]
wave absorption materials have become a research hotspot with particular emphasis on achieving efficient
broadband absorption, which remains a critical challenge in the field [7-10] .

Among those diverse EM wave absorption materials, magnetic-dielectric synergistic composites integrate
the benefits of both magnetic and dielectric components to achieve superior absorption performance [11,12] .
The magnetic component induces magnetic loss, while the dielectric component contributes to dielectric
loss [13-15] . The synergistic magnetic-dielectric effect has enabled multiple loss mechanisms, thereby
significantly enhancing the material’s EM wave attenuation capacity and achieving a more effective
absorption outcome [16,17] .

Core-shell EM wave absorption materials with specialized heterojunction interfaces offer distinct
advantages, providing a synergistic loss effect to dissipate the incident energy [18,19] . This interface features
unique electronic structures and physicochemical properties that generate various specific response
behavior, thereby broadening the effective absorption bandwidth [20,21] . Core-shell structured materials
present novel strategies in advanced EM wave absorption. Numerous studies have documented that the
core-shell magnetic-dielectric composites with enhanced absorption performance, integrating magnetic
materials (alloys, Fe O , ferrites, and MOFs-derivatives) with dielectric components of choice, including
4
3
transition metal sulfides, carbides, and polymers, such as CoFe@C@C , CNC/Fe O @C , ZnFe O 4
[22]
[23]
4
2
3
@PPy , and CoFe O @Fe C@NiO .
[24]
[25]
2
3
4
In this study, magnetic FeCoNi and dielectric ZnIn S were combined to construct core-shell structured
2 4
microspheres with magnetic-dielectric synergy, utilizing chemical reduction, oil bath, and in-situ annealing
techniques to achieve tunable EM properties. The selection of magnetic components focused on FeCoNi
alloys, which are well-known magnetic materials with high saturation magnetization and permeability,
[26]
leading to significant magnetic loss and a strong magnetic response to EM wave . In contrast, the choice of
dielectric shell components has predominantly centered on binary transition metal sulfides, such as MoS ,
[27]
2
[29]
CuS , and NiS , while research on ternary metal sulfide EM wave absorption materials remains limited.
[28]
2
As a result, there are considerable challenges and opportunities for advancement in this domain. ZnIn S , a
2 4
representative ternary metal sulfide, has been extensively investigated in the field of photocatalysis due to its
unique photoelectric properties, low toxicity, good chemical stability, and semiconductor characteristics,
making it an appealing candidate for further exploration in EM wave absorption . ZnIn S has the
[30]
2 4
advantage of being able to enhance the polarization intensity through phase regulation and the introduction
of crystal defects. Meanwhile, the band gap of ZnIn S (2.4-2.6 eV ) lies between that of CdIn S (2.0-
[31]
2 4
2 4
2.37 eV ) and ZnGa S (3.18 eV ), possessing moderate conductivity and dielectric loss capability. Despite
[32]
[33]
2 4
ZnIn S having relatively low conductivity , its combination with FeCoNi in a core-shell structure allows
[34]
2 4
the conductive channels of FeCoNi to penetrate ZnIn S , thereby enhancing internal charge transfer.
2 4
Moreover, the interface formed between these components plays a crucial role in enhancing conductivity,
ultimately optimizing EM wave absorption performance. Thus, this work presents FeCoNi@ZnIn S
2 4
composites, leveraging synergistic core-shell composites to overcome challenges in achieving efficient and
tunable absorption.