Heteropoly acid-assisted carboxymethyl cellulose-soft template self-assembly synthesis of three-dimensional hybrid layered porous carbon for supercapacitors

This study introduces an innovative, environmentally friendly method for controlling the morphology, size, spatial structure and activity of three-dimensional hybrid layered porous carbon (HLPC). The hydrothermal reaction is carried out in a microreactor through a synergistic interaction between triblock copolymer (F127) and ammonium molybdate phosphate (APMo). Carboxymethyl cellulose undergoes acid-catalyzed hydrolysis and self-assembles into HLPC at the interface between the microreactor and the solution. The structural integrities and dimensional attributes of HLPC are modulated by adjusting the hydrothermal time to allow for swelling, tearing or further development. The addition of varying amounts of APMo allows customization of HLPC's spatial structures, such as layered, curled or folded configurations. HLPC demonstrates efficient ion storage and transmission channels, a hydrophilic surface, high reactivity and robust electrochemical performance. When tested in a 6 mol·L^-1 KOH electrolyte, HLPC achieved a specific capacitance of 318 F·g^-1 at a current density of 0.5 A·g^-1 and maintained a retention of 96 % after 10,000 charging/discharging cycles at 10 A·g^-1. Additionally, the symmetrical supercapacitor with HLPC in an ionic liquid electrolyte (1-butyl-3-methylimidazolium tetrafluoroborate) exhibited a specific capacitance of 102 F·g^-1 at 0.1 A·g^-1 and an energy density of 31.88 W·h·kg^-1.