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Nitrogen-doped porous graphene as a highly efficient cathodic electrocatalyst for aqueous organic redox flow battery application

Author:
Cao, Jianyu, Zhu, Zhentao, Xu, Juan, Tao, Meng, Chen, Zhidong
Source:
Journal of materials chemistry A 2017 v.5 no.17 pp. 7944-7951
ISSN:
2050-7496
Subject:
active sites, batteries, catalysts, durability, electrochemistry, energy, glassy carbon electrode, graphene, nitrogen, protons, pyrolysis, redox reactions, storage technology
Abstract:
The redox flow battery (RFB) is considered one of the most attractive energy storage technologies because of its high efficiency, long service life and great safety. In this work, nitrogen-doped porous graphene (NPG) was achieved by embedding nitrogen atoms into the graphitic matrix via a sacrificial-template-assisted pyrolysis approach, and then was employed to catalyze electrochemically the redox reaction of 1,2-dihydrobenzoquinone-3,5-disulphonic acid (BQDSH₂) for aqueous organic RFB application. The electrocatalytic performances of this catalyst toward the BQDS/BQDSH₂ redox couple were greatly enhanced, including a 6.7 times higher rate constant and much lower peak potential separation value compared to those of a glassy carbon electrode. Furthermore, a 9,10-anthraquinone-2,7-disulfonic acid (AQDS)/BQDS RFB with NPGs as the cathodic BQDS/BQDSH₂ catalyst exhibited a maximum power density of ca. 62.4 mW cm⁻², about 3.3 times higher than that of the pristine RFB without NPGs, and a minimal discharge capacity fade during the cycling test. The abundant nitrogen defects in NPGs are beneficial to the BQDS/BQDSH₂ redox reaction by providing active sites and enhancing the transfer rate of protons and reactants, contributing to the improvement of AQDS/BQDS RFB performance.
Agid:
6425076