ABSTRACT High‐power density electronic devices face intertwined challenges of localized thermal shock and electromagnetic interference, constraining their performance, reliability, and lifespan. Herein, this study proposes a heterodimensional interface engineering strategy to fabricate dual‐functional phase change regulator capable of synergistically achieving efficient thermal management and microwave dissipation. By integrating paraffin wax (PW) with a robust three‐dimensional polypyrrole (PPy) network decorated with vertically aligned MoS 2 nanosheets, the resulting PW‐PPy@MoS 2 phase change regulator achieves a high phase change enthalpy of 108.2 J·g −1 . In device‐level testing, PW‐PPy@MoS 2 significantly reduces the peak temperature of high‐power chips and contributes to extended device longevity. Electromagnetically, PW‐PPy@MoS 2 exhibits outstanding microwave absorption, with a minimum reflection loss of ‐73.18 dB and a broadband absorption of 6.56 GHz, originating from its well‐designed hierarchical architecture. 3D PPy@MoS 2 conductive network and heterogeneous interfaces synergistically optimize impedance matching, while simultaneously activating a collaborative dissipation mechanism dominated by interfacial polarization, supplemented by dipole relaxation, conductive loss, and multiple scattering. Simulations and experiments further confirm its promising potential in radar cross‐section reduction and wireless communication signal shielding. This work provides a promising heterodimensional material design solution to the integrated thermal‐electromagnetic management challenges in high‐power integrated electronics.
Li et al. (2026) studied this question.