The development of new electrode materials for energy storage in redox flow batteries

Abstract

Carbon-based electrodes currently used in the all-vanadium flow battery suffer from loss of electrode material due to the oxidation of C to CO2. Therefore, it is important to develop new electrodes, considering materials that have been used in electrochemical applications, such as the dimensionally stable anodes (DSA). The electrocatalytic characteristics of DSA change with the coating composition and the preparation method and can be adjusted to the electrochemical process. The reversibility of the V(IV)/V(V) reactions and the endurance to the corrosive conditions of the positive electrolyte were the main criteria to select a desirable electrochemical performance. This was evaluated with CV, charge-discharge testing, SEM, EDS, XRD, EIS, and the morphology factor (ϕ). The carbon-based electrodes showed overlapping of the C oxidation reactions in the potential window of the V(IV)/V(V) reactions, and inferior selectivity towards them in the charge-discharge test. The Au and Pt electrodes showed parasitic reactions in the potential window for the V(IV)/V(V) reactions. The Ru DSA electrode showed parasitic reactions and deactivated in the charge-discharge test. The Ir DSA prepared by different methods showed similar electrochemical performance and selectivity towards the V(IV)/V(V) redox reactions, and the main difference was in the damage of the coating after the charge-discharge test. The DSA prepared by the polymeric precursor method suffered the biggest damage with a change in ϕ of 41 %, the DSA prepared by the ionic liquid method had a difference in ϕ of 24 %, and the change of ϕ in the DSA prepared by the template method was 23 %. The DSA prepared with different substrate geometries suffered a bigger change in the ϕ with a 78 % change for the mesh substrate and 54 % change for the micromesh substrate.

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Identifiers

ORCID for Nicolas Kinich Hernandez Sanchez: orcid.org/0000-0001-5177-9622

ORCID for Carlos Ponce De Leon Albarran: orcid.org/0000-0002-1907-5913

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