Hierarchical porous carbon derived from elm bark mucus for efficient energy storage and conversion

Abstract The exploration of thermally chargeable supercapacitors has gained intensive interest. However, their practical application is still restricted by complex integration, poor Seebeck coefficient, and unsatisfactory conversion efficiency. Herein, we report a high-performance device with a simplified symmetric configuration based on activated carbon derived from elm bark mucus. Due to high specific surface area, hierarchical porosity, and moderate surface chemistry, such system displays excellent electrochemical properties such as high capacitance, rate capability and thermoelectrical behavior. When coupling with a concentrated electrolyte (26 m KOAc), a 2.0 V symmetric supercapacitor can be fabricated and a maximum energy density of 33.6 Wh kg−1 at power density of 500 W kg−1. A high-power density of 20 kW kg−1 also can be achieved at 21.7 Wh kg−1. Moreover, thermally rechargeable devices with quasi solid-state electrolyte exhibit a high open circuit voltage of ∼24.02 mV and a considerable Seebeck coefficient of about 1.97 mV K−1, indicating satisfying thermoelectrical performances. This work not only demonstrates the applicability of elm bark mucus-derived carbon as advanced materials for energy application, but also provides a new perspective for the development of multifunctional devices.