Ion accumulation-induced capacitance elevation in a microporous graphene-based supercapacitor

Bhaskar Pattanayak, Phuoc Anh Le, Debashis Panda, Firman Mangasa Simanjuntak, Kung Hwa Wei, Tan Winie, Tseung Yuen Tseng*

*此作品的通信作者

研究成果: Article同行評審

10 引文 斯高帕斯(Scopus)

摘要

High-performance porous 3D graphene-based supercapacitors are one of the most promising and challenging directions for future energy technologies. Microporous graphene has been synthesized by the pyrolysis method. The fabricated lightweight graphene with a few layers (FLG) has an ultra-high surface area of 2266 m2 g−1 along with various-sized micropores. The defect-induced morphology and pore size distribution of the fabricated graphene are examined, and the results show that the micropores vary from 0.85 to 1.9 nm and the 1.02 nm pores contribute 30% of the total surface area. The electrochemical behaviour of the electrode fabricated using this graphene has been studied with various concentrations of the KOH electrolyte. The highest specific capacitance of the graphene electrode of 540 F g−1 (close to the theoretical value, ∼550 F g−1) can be achieved by using the 1 M KOH electrolyte. This high specific capacitance contribution involves the counter ion adsorption, co-ion desorption, and ion permutation mechanisms. The formation of a Helmholtz layer, as well as the diffusion of the electrolyte ions, confirms this phenomenon. The symmetrical solid-state supercapacitor fabricated with the graphene electrodes and PVA-KOH gel as the electrolyte exhibits excellent energy and power densities of 18 W h kg−1 and 10.2 kW kg−1, respectively. This supercapacitor also shows a superior 100% coulombic efficiency after 6000 cycles.

原文English
頁(從 - 到)27082-27093
頁數12
期刊RSC Advances
12
發行號42
DOIs
出版狀態Published - 23 9月 2022

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