Polymer Dehalogenation-Enabled Fast Fabrication of N,S-Codoped Carbon Materials for Superior Supercapacitor and Deionization Applications

Doped carbon materials (DCM) with multiple heteroatoms hold broad interest in electrochemical catalysis and energy storage but require several steps to fabricate, which greatly hinder their practical applications. In this study, a facile strategy is developed to enable the fast fabrication of multiply doped carbon materials via room-temperature dehalogenation of polyvinyl dichloride (PVDC) promoted by KOH with the presence of different organic dopants. A N,S-codoped carbon material (NS-DCM) is demonstratively synthesized using two dopants (dimethylformamide for N doping and dimethyl sulfoxide for S doping). Afterward, the precursive room-temperature NS-DCM with intentionally overdosed KOH is submitted to inert annealing to obtain large specific surface area and high conductivity. Remarkably, NS-DCM annealed at 600 °C (named as 600-NS-DCM), with 3.0 atom % N and 2.4 atom % S, exhibits a very high specific capacitance of 427 F g–1 at 1.0 A g–1 in acidic electrolyte and also keeps ∼60% of capacitance at ultrahigh current density of 100.0 A g–1. Furthermore, capacitive deionization (CDI) measurements reveal that 600-NS-DCM possesses a large desalination capacity of 32.3 mg g–1 (40.0 mg L–1 NaCl) and very good cycling stability. Our strategy of fabricating multiply doped carbon materials can be potentially extended to the synthesis of carbon materials with various combinations of heteroatom doping for broad electrochemical applications.