N–O–S Co-doped Hierarchical Porous Carbons Derived from Calcium Lignosulfonate for High-Performance Supercapacitors

We propose a simple and low-cost synthesis of N–O–S co-doped hierarchical porous carbons (MGC-x) by direct carbonization of calcium lignosulfonate. MGC-x possesses a large surface area (∼1500 m2 g–1) and high mesopore ratio (>40%) and heteroatom content. In the three-electrode system, MGC-700 and MGC-800 exhibit high specific capacitances of 417 and 312 F g–1 at 0.5 A g–1 and 184 and 170 F g–1 even at 100 A g–1 using a 1 M H2SO4 electrolyte....