High-entropy Co-Zn-Cd-Cu-Mn sulfide ceramic nanoflowers as efficient microwave absorbers with photothermal performance

Abstract

The high-entropy concept has been widely recognized as a promising strategy for enhancing microwave absorption (MA) performance. However, systematic studies on how crystallinity affects the MA behavior of high-entropy materials remain scarce, limiting further performance optimization. In this context, nanoflower-structured highentropy CoZnCdCuMn sulfide ceramics with different crystallinities were prepared via solvothermal synthesis and post-annealing, revealing a nonmonotonic crystallinity-dependent MA behavior. Among the samples, CoZnCdCuMnS-500 with intermediate crystallinity achieves an optimal balance between dielectric loss and impedance matching, delivering superior MA performance with a minimum reflection loss of -50.79 dB. Furthermore, CoZnCdCuMnS-500 was incorporated into a polymer matrix to fabricate a composite film, which exhibits rapid photothermal response and good cycling stability, highlighting its potential for electromagnetic protection in cold and complex environments. This work elucidates the critical role of crystallization state in governing the MA performance of high-entropy sulfides and provides new insights into the structural design and performance optimization of microwave absorbers.