Polyimide/Ionic Crystal-Based Hybrid Electrolyte for a Self-Powered Multistage Fire Alarm

Fire seriously threatens human life and causes a large number of losses. Common fire alarms are composed of sensors and power supply, but damage of any components at high temperatures will lead to their failure, which poses a challenge to the application of stable and sensitive alarms in an extreme environment. Hence, we report a nonflammable self-powered alarm, which integrates energy supply and a multistage sensor. The self-powered alarm is a thermal-responsive smart supercapacitor composed of high-temperature-resistant polyimide nanofibers and ionic crystals. Thanks to the sharp conductivity change (more than 3 orders of magnitude) of the ionic crystal at the phase transition point, the self-powered alarm shows stable energy storage performance at room temperature (maintained a high potential of above 1.3 V) and sensitive temperature response in a fire. Furthermore, due to the structural designability of the ionic crystal, the phase transition point can be adjusted according to demand (e.g., 40, 60, and 90 °C). Therefore, the polyimide/ionic crystal-based self-powered alarm can achieve a multistage fire alarm based on temperature. These unique properties of a self-powered smart alarm will effectively reduce the loss caused by fire and protect human life.