As firefighting operations grow more complex and hazardous, there is a critical demand for protective gear that not only shields against extreme heat but also actively monitors temperature in real time. Now, researchers from Wuhan Textile University, led by Professor Hualing He, have unveiled a breakthrough anisotropic thermoelectric aerogel inspired by the structural precision of human muscle. This novel aramid nanofiber-based composite, dubbed ACMCA, integrates superior thermal insulation with high-efficiency energy conversion—offering a promising path toward intelligent, self-powered fire safety apparel.

Engineered through a directional freeze-drying process, ACMCA forms a highly ordered porous network that mimics muscle tissue, enabling directional heat transport and electrical conductivity. The result is a flexible, lightweight (0.038 g cm^-3) aerogel with a low thermal conductivity of just 0.048 W m^-1 K^-1 and an impressive Seebeck coefficient of 46.78 μV K^-1. These synergistic properties allow ACMCA to convert heat gradients directly into electrical signals—without relying on external power—enabling precise temperature monitoring in real time.

In practical tests, ACMCA demonstrated rapid and repeatable temperature response. When integrated into firefighting clothing, the material triggered a multistage high-temperature alarm system within just 1.43 seconds upon exposure to flame, effectively providing early warning signals across a broad temperature range (50–400 °C). Unlike conventional sensors that require batteries or external circuits, ACMCA’s self-powered architecture simplifies system design and enhances operational reliability under extreme conditions.

Mechanically, the muscle-inspired structure provides not only anisotropic heat transfer but also exceptional resilience. ACMCA withstood repeated bending, stretching, and compression without loss of performance, maintaining over 85% voltage stability even after 300 deformation cycles. The aerogel’s robustness stems from strong hydrogen bonding and van der Waals interactions between its functionalized MXene, MWCNTs, and Ag nanowires, forming a highly cross-linked, conductive 3D network. Furthermore, its flame-retardant behavior is reinforced by the formation of a protective TiO₂-rich char layer, enhancing both thermal stability and fire resistance.

Beyond temperature sensing, the composite aerogel can be functionalized for gas detection. When combined with CH₃NH₃PbI₃, the ACMCA-M variant exhibited a strong visual color shift and high selectivity toward ammonia (NH₃), a toxic and explosive gas common in industrial fires—further extending the multifunctionality of this platform.

With its integration of insulation, energy harvesting, real-time sensing, and structural durability, the ACMCA aerogel represents a paradigm shift in wearable safety materials. Its scalable and environmentally friendly fabrication method is also compatible with roll-to-roll manufacturing, paving the way for widespread adoption in advanced firefighting suits, industrial safety gear, and other intelligent high-temperature applications.