Waste asphalt derived hierarchically porous carbon for high-performance electrocatalytic hydrogen gas capacitors

Along with the surging demand for energy storage devices, the cost and availability of the materials remain dominant factors in slowing down their industrial application. The repurposing of waste asphalt into high-performance electrode materials is of significant interest, as it holds the potential to circumvent energy and environmental issues. Here we report the controllable synthesis of asphalt-derived mesoporous carbon as an active material for electrocatalytic hydrogen gas capacitor (EHGC). The hierarchically porous carbon (HPC) with a high surface area of 1943.4 m2 g⁻1 can operate in pH universal aqueous electrolytes in EHGC. It displays a specific energy and power density of 57 Wh/kg and 554 W/kg in neutral electrolyte as well as 52 Wh/kg and 657 W/kg in 2 M H3PO4. Additionally, the charge storage mechanism of HPC-EHGC is studied with the help of Raman and XPS spectroscopy, which further confirm the reversibility of the process. Furthermore, the assembled HPC-EHGC device displays a remarkable discharge capacitance of 170 F g⁻1 with an excellent capacitance retention rate of 100 % up to 20000 cycles at 10 A g⁻1 and 25 ℃ in 2 M H3PO4. This work introduces a novel approach to converting asphalt waste into high-performance carbon for EHGC, achieving superior performance over commercial materials. By simultaneously addressing environmental waste issues and advancing energy storage technology, this study makes a significant contribution to the fields of sustainable materials science and next-generation battery development.