A Dual-Functional Surfactant Strategy for In-Situ Sulfur Doping and Pore Engineering of Cyclodextrin-Derived Carbon Microspheres toward Supercapacitor and Desalination Applications

Abstract

Supercapacitors, leveraging their advantages of rapid charge/discharge capability and long cycle life, demonstrate significant potential in both energy storage and capacitive deionization desalination. However, the synergistic regulation of the surface chemistry and pore structure of carbon electrodes remains a challenge. To address this, this study proposes a bifunctional surfactant-assisted structural modification strategy. Through in-situ sulfur doping and fine-tuned pore structure engineering, sulfur-doped porous carbon microspheres (ACCM-2) were successfully synthesized via a combined hydrothermal and multistep pyrolysis process, using β-cyclodextrin as the carbon source, Pluronic F127 as a soft template, and sodium lignosulfonate as both a surfactant and sulfur source. ACCM-2 possesses a high specific surface area (828.67 m 2 g -1 ) and a well-developed microporous structure. As a supercapacitor electrode, it delivers a specific capacitance of 173.1 F g -1 at a scan rate of 1 mV s -1 . Furthermore, in terms of desalination performance, ACCM-2 achieves a high salt adsorption capacity of 30.2 mg g -1 in an 800 mg L -1 NaCl solution. This work provides a simple and effective route for designing carbon materials from biomass derivatives for applications in both energy storage and seawater desalination.