E‐perlite@Graphene‐Based Thermal Isolation Triboelectric Nanogenerator for Abnormal Engine Vibration Monitoring

Abstract Triboelectric nanogenerator (TENG) is burgeoning as both a promising energy harvester and a self‐powered sensor. However, the mechanical strength, flexibility, and overall functionality of TENGs are irreversibly impacted by the chemical and physical changes of the polymer at high temperatures. Here, core–shell structured expanded‐perlite@graphene particles are conveniently synthesized by high‐temperature carbonization reaction, which are then introduced into polydimethylsiloxane (PDMS) to form a robust composite foam (EPGP) with excellent thermal insulation and flame retardancy. The thermal resistance of the EPGP (0.0145 m 2 K W −1 ) is ≈2.1 times that of PDMS, while reducing heat/smoke release rates by 84%/44% and total heat/smoke release by 44%/76%. For energy conversion and mechanical sensing, the EPGP‐based TENG shows 186 V open‐circuit voltage and 0.3 µA cm −2 short‐circuit current at room temperature, which is 2.7 and 3.2 times higher than the PDMS‐based TENG. Even at 200 °C, the output also remains stable at 106 V and 0.16 µA cm −2 . The as‐designed TENGs in monitoring the engine's malfunction/compressor operation at high‐temperatures and extended periods are realized by detecting abnormal vibrations. The instant monitoring of the engine status shows graphically the performance degradation, thus functioning as a new indicator that informs fault while driving, while advancing thermal‐insulation composites for TENG‐based microelectronics in extreme environments.