Sodium polyacrylate-based porous carbon fabricated by one-step carbonization and its outstanding electrochemical properties in supercapacitor

A sodium polyacrylate-based porous carbon was fabricated by direct carbonization without additional activator and template. The by-products of Na2CO3 and CO formed in pyrolysis process of precursor served as self-template, self-activation agent, and pore-forming agent. The effects of carbonization temperature and atmosphere type on the structure and electrochemical performance for the resulted porous carbon were investigated. The optimized sodium polyacrylate-based porous carbon (PC-600) synthesized at 600 °C under argon (Ar) atmosphere exhibits exceptional capacitance characteristics, a unique honeycomb-like structure, a large surface area of 1100 m2 g−1 and a moderate oxygen content of 7.8 %. PC-600 was identified as an advanced electrode material for supercapacitor assembly. In a three-electrode system with 6 M KOH electrolyte, PC-600 suggests a specific capacitance of 270 F g−1 at 1 A g−1 with a retention rate of 79 % at 20 A g−1. The symmetrical supercapacitor assembled using PC-600 shows a capacitance of 197 F g−1 and an energy density of 6.7 Wh kg−1 along with a 255.0 W kg−1 power density at 1 A g−1 in 6 M KOH, a 95 % capacity retention undergoing 10,000 cycles at 2 A g−1, and an approximate 100 % coulomb efficiency. Moreover, in 1 M Li2SO4 electrolyte, the PC-600 based supercapacitor delivers a 19.0 Wh kg−1 energy density along with a 489.0 W kg−1 power density, and still deserves 9.0 Wh kg−1 even at 1.8 KW kg−1. This study demonstrates that the porous carbon derived from sodium polyacrylate exhibits an outstanding electrochemical performance while providing practical value-added exploitation ideas for polymer use in electrochemical energy storage fields.