Preparation of nitrogen and sulfur co-doped tubular porous carbon derived from Ceiba speciosa flowers for supercapacitors

The utilization of biomass for producing porous carbon presents significant promise for supercapacitor electrode materials. This work introduces an efficient and environmentally friendly two-step synthesis method for preparing Ceiba speciosa flowers derived porous carbon (CSDC). The findings highlight the tubular porous character of the resulting carbon material. Notably, the sample (CS-700-T2) using thiosemicarbazide as a dopant results in a pore volume of 0.949 cm³·g⁻¹ and an exceptionally high SSA of up to 2090 m²·g⁻¹. CS-700-T2 exhibits outstanding electrochemical performance, achieving a capacitance of 355.3 F·g⁻¹ at 0.5 A·g⁻¹. Its exceptional rate capability is evidenced by maintaining 83.1 % capacitance at 20 A·g⁻¹. In a symmetric CS-700-T2||CS-700-T2 electrode system, the capacitance remains at 97.3 % after 10,000 cycles at 5 A·g⁻¹. Furthermore, to enhance the energy density, Na₂SO₄ was used as the electrolyte, successfully expanding the operating voltage to 0–1.6 V. This adjustment significantly increases energy density, reaching 26.2 Wh·kg⁻¹. Therefore, the synthesized CS-700-T2 material, with its exceptional electrochemical performance, stands out as a powerful contender for future SC electrode materials.