Assessment of N-doped carbon microcapsules-based electrochemical capacitors in different electrolytes

Abstract

The performance of electrochemical capacitors (ECs) mainly depends on the electrode material and electrolyte. Electrodes are mainly made of carbon materials and organic electrolytes are commonly used in commercial ECs. Environmental concerns have boosted the study of aqueous-based ECs. In this study, nitrogen-doped carbon microcapsules were synthesized by a templating method, obtaining an apparent surface area of 1560 m2 g−1 and a nitrogen content of 5.5 wt%. Such N-doped carbon microcapsules were characterized in a three-electrode configuration to gather information about their electrochemical stability, showing remarkable results in acidic (1 M H2SO4) and neutral (0.5 M Na2SO4) electrolytes. Symmetric ECs based on N-doped carbon microcapsules were assembled and evaluated in both aqueous and organic electrolytes. Ragone plots revealed that N-doped carbon microcapsules-based EC in a neutral electrolyte exhibited good electrochemical performance using an operating voltage of 1.7 V, leading to a capacitance retention (C/C0) of 90% after 10,000 cycles. Additionally, an analogous EC assessed in an organic electrolyte exhibited a noticeable stability compared to that of YP-50F used as electrode material in commercial ECs. The morphology of the carbon materials, as well as the N doping, explain the outstanding performance in the different electrolytes analyzed.This study forms part of the Advanced Materials programme and was supported by MCIN with funding from the European Union NextGenerationEU (PRTR-C17.I1) and by Generalitat Valenciana (MFA/2022/001), DST would like to thank the CIDEGENT 2023 project (Plan GenT) from Generalitat Valenciana (CIDEXG/2023/2) and AEI through the project PID2021–122248OB-I00 (MCIN/AEI /10.13039/501100011033/FEDER, UE)