Multi-Doped Interconnected Carbon Nanospheres for High-Performance Supercapacitor

Heteroatom doping is an effective modification to improve electrochemical performance of carbon materials as electrodes in storage devices and multi-doping works better because of the synergistic effect. In this report, N/O/S multi-doped carbon nanospheres (SLS/PANI-700) are prepared from crosslinking hydrogel beads of polyaniline and sodium lignosulfonate. The addition of sodium lignosulfonate improves the electrochemical performance of PANI-based carbon significantly by changing micromorphology, building interconnected network, and offering diverse doping. SLS/PANI-700 has an ultrahigh specific surface area of 2861 m² g⁻¹, well-developed hierarchically porous structure, interconnected conducting carbon network, and high N and O concentration. Take these advantages, it delivers a very high capacitance of 487.7 F g⁻¹ at 1 A g⁻¹, and a superior rate retention with a capacitance of 373.6 F g⁻¹ at a high current density of 20 A g⁻¹ as electrode material. The assembled symmetric supercapacitor device exhibits a very high energy density of 43.68 Wh kg⁻¹ at 488.98 W kg⁻¹ and keeps 21.18 Wh kg⁻¹ under a high power density of 8664.54 W kg⁻¹. Based on these properties, SLS/PANI-700 possesses great promising potential as electrode material for advanced supercapacitors.