Triazine based polyimide framework derived N-doped porous carbons: a study of their capacitive behaviour in aqueous acidic electrolyte

Abstract

Nitrogen-doped porous carbon materials have been synthesized from nitrogen and oxygen rich triazine based polyimide (TPI-P/TPI-N) frameworks using ZnCl₂ as an activating agent at different temperatures (600 and 700 °C) for electrochemical energy storage applications. The morphology and structural features of the materials were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption/desorption isotherms, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopic techniques. The resultant carbon materials possess large specific surface area and rich nitrogen contents. In particular, the material obtained at 700 °C (TPI-P-700) exhibits a surface area of up to 1650 m² g⁻¹ and a nitrogen content of up to 6.3%, and shows an excellent specific capacitance of 423 F g⁻¹ in an aqueous acid electrolyte (1 M H₂SO₄) in a three electrode system. Moreover, the material also demonstrates nearly 100% capacitance retention up to 10 000 charge–discharge cycles. A symmetrical supercapacitor device assembled using TPI-P-700 as an active material delivered an energy density of 10.5 W h kg⁻¹ at 0.5 A g⁻¹.