Influence of foaming temperature on the structure of coal-based carbon foams and the electrochemical performance of electrical double-layer capacitors

The rational design of coal substrate structure is an effective approach to developing high-efficiency coal-based supercapacitor electrode materials. This study investigates the preparation of coal-based carbon foam (NCF) from strongly-bonded bituminous coal using an atmospheric pressure self-foaming method at various temperatures within the plasticity interval. The resulting NCF was then activated with KOH to produce activated carbon foam (ACF), which was used as electrode material in Electrical Double-Layer Capacitors (EDLCs). Notably, NCF-460, obtained at the maximum fluidity temperature (460 degrees C), exhibits the highest open porosity (88.29 %) and the lowest bulk density (0.166 g cm- 3). The three-dimensional interconnected pore structure of NCF facilitates the effective penetration of KOH, providing more active sites. Consequently, ACF-460 demonstrates superior specific surface area (2370.64 m2 g- 1) and mesopore volume ratio (44.04 %), along with remarkable energy density (59.34 Wh kg- 1) and cycling stability in EDLC applications. This study offers an effective approach for converting coal into advanced electrode materials, which provides a new idea for the materialized and high value-added utilization of coal.