Tuning the Nanoporous Structure of Carbons Derived from the Composite of Cross-Linked Polymers for Charge Storage Applications

Controlling the porosity of carbon-based electrodes is key toward performance improvement of charge storage devices, e.g., supercapacitors, which deliver high power via fast charge/discharge of ions at the electrical double layer (EDL). Here, eco-friendly preparation of carbons with adaptable nanopores from polymers obtained via microwave-assisted cross-linking of poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) is reported. The polymeric hydrogels possess porous and foam-like structures, giving excellent control of porosity at the precursor level, which are then subjected to activation at high temperatures of 700-900 degrees C to prepare carbons with a surface area of 1846 m(2) g(-1) and uniform distribution of micro-, meso-, and macropores. Then, graphene as an additive to hydrogel precursor improves the surface characteristics and elaborates porous texture, giving composite materials with a surface area of 3107 m(2) g(-1). These carbons show an interconnected porous structure and bimodal pore size distribution suitable for facile ionic transport. When implemented in symmetric supercapacitor configuration with aqueous 5 mol L-1 NaNO3 electrolyte, a capacitance of 163 F g(-1) (per average mass of one electrode) and stable evolution of capacitance, coulombic, and energy efficiency during 10 000 galvanostatic charge/discharge up to 1.6 V at 1.0 A g(-1) have been achieved.

Automated summary

Controlling the porosity of carbon-based electrodes is crucial for enhancing the performance of charge storage devices such as supercapacitors. This study demonstrates an eco-friendly method for preparing carbon materials with optimized pore structures, leading to improved surface characteristics and interconnected porous structure suitable for ionic transport. The composite materials show stable capacitance and energy efficiency, making them promising for use in supercapacitors.