Capacitive behavior of electrodes prepared using tragacanth gum modified at various ratios and temperatures

Abstract

In the fields of energy conversion and storage, renewable, affordable, and environmentally benign electrode materials have garnered a lot of interest. Tragacanth gum (TG), a natural polymer, exhibits a high degree of biocompatibility; however, it is still difficult to obtain high conductivity. This study uses a TG carbon precursor and ZnCl₂ as an active agent at 600–900 °C for 2 hours under an N₂ atmosphere, which, to the best of our knowledge, is a simple approach for creating porous carbon materials with a high nitrogen content. The resulting TGN-3 sample has a nitrogen content of up to 1.23 weight percent and a high specific surface area of 3595.77 m² g⁻¹. Additionally, the N-doped carbon shows good electrochemical properties (with a specific capacitance of 124.78 F g⁻¹ in 6 M KOH at a current density of 1 A g⁻¹). Moreover, a TGN-3@Ni composite was prepared from the sustainable carbon source TGN-3 using a straightforward hydrothermal synthesis process. As an electrode material, it demonstrated good electrochemical properties with high rate capability and a specific capacitance of 319.9 F g⁻¹ in 6 M KOH at a current density of 5 A g⁻¹. Then, using TGN-3 as the negative electrode, TGN-3@Ni as the positive electrode, and 6 M KOH as the electrolyte solution, an asymmetric supercapacitor (ASC) was fabricated. With a specific capacitance of 40.06 F g⁻¹ at 1 A g⁻¹ and a high energy density of 16.07 Whkg⁻¹ at a power density of 881.07 W kg⁻¹, this supercapacitor demonstrated good electrochemical performance. It also demonstrated exceptional cycle stability, maintaining 96.12% of its initial specific capacitance after 8000 cycles at 5 A g⁻¹. Consequently, these experimental results confirm that porous carbon materials with a high nitrogen content can be prospective electrode materials for supercapacitors.