Sucrose–Thiourea-Derived Nitrogen and Sulfur Co-doped Hierarchically Porous Carbon Nanosheets as a High-Performance Negative Electrode for Sodium-Ion Batteries

Nitrogen-containing porous carbon derived from sucrose and thiourea by an environmentally friendly and economically feasible technique has been explored as a negative electrode for sodium-ion batteries (SIBs). Aforesaid sucrose–thiourea-derived carbon (STU) contains micro-, meso-, and macroporous particles with a significant surface area of 2070 m2/g. When examined as an negative electrode in SIB applications, STU delivers an appreciable electrochemical performance upon moderate-rate (50 mA/g) and high-rate (1.6 A/g) charge conditions. A steady-state progressive capacity of 285 mAh/g is observed at 50 mA/g after 100 cycles. Further, an STU negative electrode delivers an appreciable capacity of 216 mAh/g after 600 cycles with 77% capacity retention. Furthermore, a high reversible capacity of 132 mAh/g was obtained at 1.6 A/g after 230 cycles. The excellent electrochemical activity of an STU negative electrode for SIB application is believed to be due to the presence of a combination of micro-, meso-, and macropores along with a high surface area and more edges and defect sites of carbon.