Flexible, temperature-tolerant supercapacitor based on hybrid carbon film electrodes

Flexible supercapacitors have advanced rapidly in recent years and contributed to the development of wearable electronics. However, the operating temperature of the flexible supercapacitors usually falls within a narrow range, because of the constraints of the electrode materials and the electrolytes. Here, we report a flexible supercapacitor that can operate at extreme temperatures (down to −40 °C and up to 200 °C) with excellent electrochemical property and high durability. This device allows a maximum area specific capacitance of 330 mF/cm2. It has 2 F/cm3 volume specific capacitance and 1.7 mWh/cm3 energy density. The high stability of this supercapacitor enables 90% capacitance retention after 105 cycles. Moreover, deformation at extreme temperature does not reduce its energy storage ability.