The increase in conventional energy consumption in the world has increased the concern in renewable energy studies such as solar, biomass, geothermal and wind. Due to fluctuating renewable energy production, difficulties have occurred in the instantaneous supply of high energy needs. Energy storage systems have significant potential as a large-scale energy storage technology to effectively store the fluctuating power generated by renewable energy. Vanadium redox flow battery (VRFB) is one of the promising options with their long cycle life, low cost, scalability and safety properties. In order to improve the performance of VRFB systems and to increase the power density, the investigations are carried out on the improvement of battery components such as electrolyte, membrane and electrode. The electrode is doped with carbon and metal-based electrocatalyst to enhance the performance of felt electrodes used in VRFB systems, besides thermal, chemical and electrochemical treatments ^1–3. Because the electrochemical behavior and electrochemical surface area of bare electrode has been improved with doping and treatment methods, its overpotential values have been reduced. In this study, boron electrocatalyst in the different purities (>90%, >95%, >98%) was doped into bare graphite felt with the same doping ratio. The electrochemical characteristics of developed electrode was determined by CV and EIS analysis in case it was used as positive and negative electrodes, separately. Moreover, hydrophilic properties and crystal structure of the electrode were analyzed by contact angle measurement and XRD analysis, respectively. The obtained results were compared with the bare electrode. It has been stated that the purity of the boron electrocatalyst affects the electrochemical characteristics of the graphite felt electrode used in VRFB electrodes.

Acknowledgement

The authors would like to thank the Scientific Research Projects Unit of Erciyes University for funding and supporting the projects under the contract no: FDK-2020-10376. The first named author thanks The Scientific and Technological Research Council of Turkey (TÜBİTAK) for their scholarships under “2211-C Priority Areas PhD Scholarship Program with the grant number 1649B032000390”

Reference

1. M. Taş and G. Elden, Energy Storage, Early access, 1–22 (2021).

2. J. Noack et al., J. Energy Chem., 27, 1341–1352 (2018).

3. B. Sun and M. Skyllas-Kazacos, Electrochim. Acta, 37, 1253–1260 (1992).