All-Printed Substrate-Versatile Microsupercapacitors with Thermoreversible Self-Protection Behavior Based on Safe Sol–Gel Transition Electrolytes

Thermal runaway has always been a significant safety issue that high-performance electronic devices urgently need to solve. These existing strategies are limited by the lack of reversibility and low conductivity. Here, we propose a novel thermoreversible self-protection microsupercapacitor (TS-MSC) based on a thermoresponsive polymer electrolyte to prevent thermal runaway. When heating above the low critical solution temperature (LCST), a gelation process occurs in the smart electrolyte and effectively inhibits the migration of ions, leading to a decreased specific capacitance and an increased internal resistance of the MSC. However, the electrolyte transforms to a solution state at room temperature in which ions can freely migrate. Benefiting by sol-gel transition of the smart electrolyte, the TS-MSCs can exhibit different electrochemical performances at elevated temperatures, demonstrating an active method of achieving thermoreversible and dynamic self-protection. In addition, 3D printing technology and substrate versatility provide an attractive method in the design of integrated micropower devices. Therefore, such functional TS-MSCs offer a promising strategy to solve the safety issues of the nowadays portable microelectronic devices.