Hierarchical porous carbons from carboxylated coal-tar pitch functional poly(acrylic acid) hydrogel networks for supercapacitor electrodes

Abstract

A gel carbonization strategy for the synthesis of hierarchical porous carbons (HPCs) from carboxylated coal-tar pitches (CCP) functional poly(acrylic acid) (PAA) hydrogel networks for advanced supercapacitor electrodes was reported. The amphiphilic CCP and PAA polymer could be easily self-assembled to gel by the major driving force of hydrogen bonding and π–π stacking. The HPCs containing interconnected macro-/meso-/micropores were fabricated by direct carbonization of the dried hydrogels. The resultant HPCs with a high specific surface area and total pore volume of 1294.6 m² g⁻¹ and 1.34 cm³ g⁻¹ respectively, as a supercapacitor electrode exhibit a high specific capacitance of 292 F g⁻¹ at 1.0 A g⁻¹ in two-electrode system. The electrode also exhibits ultra-long cycle life with a capacitance retention as high as 94.2% after 10 000 cycles, indicating the good electrochemical stability. Furthermore, the concept of such hierarchical architecture and synthesis strategy would expand to other materials for advanced energy storage systems, such as Na-ion batteries and metal oxides for supercapacitors.