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

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 m² 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.