Biphasic GaIn Alloy Constructed Stable Percolation Network in Polymer Composites over Ultrabroad Temperature Region

Flexible and adaptable polymer composites with high-performance reliability over wide temperature range are imperative for various applications. However, the distinct filler-matrix thermomechanical behaviors often cause severe structure damage and performance degradation upon large thermal shock. To address this issue, a general strategy is proposed to construct leakage-free, self-adaptive, stable percolation networks in polymer composites over wide temperature (77-473 K) with biphasic Ga₃₅In₆₅ alloy. The in situ micro-CT technology, for the first time, reveals the conformable phase transitions of Ga₃₅In₆₅ alloys in the polymer matrix that help repair the disruptive conductive networks over large temperature variations. The cryo-expanded Ga compensates the disruptive carbon networks at low temperatures, and flowable Ga and melted In at high temperatures conformably fill and repair the deboned interfaces and yielded crevices. As a proof-of-concept, this temperature-resistant composite demonstrates superb electrical conductivity and electromagnetic interference shielding properties and stability even after a large temperature shock (ΔT = 396 K). Furthermore, the superiority of the construction of temperature self-adaptive networks within the composite enables them for additive manufacturing of application-oriented components. This work offers helpful inspiration for developing high-performance polymer composites for extreme-temperature applications.