Regulating Interfacial Strain from Tensile to Compressive State in Transition‐Metal‐Sulfides/Carbon for High‐Performance Electromagnetic Wave Absorption

The development of high‐performance electromagnetic wave (EMW) absorbers requires precise regulation of electromagnetic parameters, yet conventional strategies such as defect engineering and heterostructure construction often result in random and static interfacial microstates, lacking the capability for targeted strain control. Herein, we propose a precursor‐based hydrothermal lattice engineering strategy to achieve programmable reversal of interfacial strain in transition metal sulfide/carbon (TMS/C) composites. Using sulfonic acid‐functionalized metal–organic frameworks (MOFs) as templates, pre‐compressive strain is introduced into the crystal lattice via controlled hydrothermal treatment. This pre‐strain serves as genetic information, guiding the derived TMS/C heterointerface to undergo a strain reversal from tensile to compressive during pyrolysis. The strain reversal optimizes d‐p orbital hybridization, enhancing both interfacial charge transfer and spin polarization. The resulting materials demonstrate exceptional electromagnetic wave absorption (EMWA) performance due to optimized impedance matching and strengthened loss mechanisms. This work provides a novel paradigm for interfacial strain engineering in designing advanced electromagnetic functional materials.