680 | Mater. Chem. Front., 2019, 3, 680--689 This journal is © The Royal Society of Chemistry and the Chinese Chemical Society 2019 Cite this: Mater. Chem. Front., 2019, 3, 680 Triazine based polyimide framework derived N-doped porous carbons: a study of their capacitive behaviour in aqueous acidic electrolyte† Namrata Deka, a Rajesh Patidar, b S. Kasthuri, c N. Venkatramaiah * c and Gitish K. Dutta * a Nitrogen-doped porous carbon materials have been synthesized from nitrogen and oxygen rich triazine based polyimide (TPI-P/TPI-N) frameworks using ZnCl 2 as an activating agent at different temperatures (600 and 700 1C) for electrochemical energy storage applications. The morphology and structural features of the materials were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 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 1C (TPI-P-700) exhibits a surface area of up to 1650 m 2 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 H 2 SO 4 ) 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 . Introduction With the global energy demands and inescapable depletion of fossil fuel based energy resources, the exploration of advanced and sustainable energy resources as well as efficient energy storage systems has attracted widespread attention in recent decades. 1–3 Electrochemical energy storage devices, such as supercapacitors and batteries, are among the frontrunners for developing clean energy storage systems. 4–7 Supercapacitors are superior to batteries in terms of rapid power delivery and quick charging due to their properties like faster charge–discharge rates, longer cyclability, reliable safety and high power density, but suffer from low energy density. 8 In the context of their low energy density, efforts have been made to design better electrode materials with an aim to maximize the specific capacitance and/or potential window. 9 Apart from metal oxide derived nanostructures 10,11 and carbon–metal oxide composites, 12 metal-free carbon based electrode materials like porous carbons, 13 graphene, 14,15 carbon nanostructures, 16 etc. are most commonly employed owing to their low cost, easy processability, good con- ductivity, high durability and high surface area. 17 In spite of the many advantages of carbon based materials, their electrochemical performance is greatly hindered by their high pore tortuosity leading to poor ionic diffusion at high current densities. 18 There- fore, rational design of 2-dimensional heteroatom-doped porous graphitic materials could effectively minimize the ion diffusion paths on the nanoscale. 19,20 Among commonly incorporated heteroatom dopants (such as N, S, O, P, and B, etc.), nitrogen doping has been extensively studied and found to modify the charge distribution of nearby carbon atoms, introduce faradaic sites for pseudocapacitive charge storage and increase the wett- ability of the materials. 21 Nitrogen doping has been accomplished by various post-treatment and pre-treatment methods including chemical vapor deposition (CVD), ammonia annealing, plasma treatment, etc. 22 However, these methods fail to control the exact positioning of dopant sites. Therefore, controlled tailoring of nitrogen species into the carbon framework can allow us to monitor the structure–property relationship of these materials. 23 Recently, porous organic polymers (POPs) have been successfully applied as nitrogen containing precursors for the a Department of Chemistry, National Institute of Technology Meghalaya, Bijni Complex, Laitumkhrah, Shillong-793003, Meghalaya, India. E-mail: gitish.dutta@nitm.ac.in b Analytical and Environmental Science Division & Centralized Instrument Facility, CSIR-Central Salt & Marine Chemicals Research Institute, Bhavnagar-364002, Gujarat, India c Department of Chemistry, SRM Institute of Science and Technology (SRMIST), Chennai-603203, Tamil Nadu, India. E-mail: nvenkat83@gmail.com † Electronic supplementary information (ESI) available: Supporting information contains synthetic schemes, electrochemical investigation data, IR and 13 C CP-MAS NMR spectra, water contact angle images, FESEM images and elemental mapping, powder X-ray diffraction, Raman spectra, deconvoluted XPS spectra and Nyquist plots. See DOI: 10.1039/c8qm00641e Received 13th December 2018, Accepted 21st February 2019 DOI: 10.1039/c8qm00641e rsc.li/frontiers-materials MATERIALS CHEMISTRY FRONTIERS RESEARCH ARTICLE Published on 22 February 2019. Downloaded on 8/25/2022 5:33:06 PM. View Article Online View Journal | View Issue