New insights into the performance of an acid-base electrochemical flow battery

• Published in: Journal of power sources 2021-09, Vol.506, p.230233, Article 230233
• Main Authors: Mundaray, Eleana, Sáez, Alfonso, Solla-Gullón, José, Montiel, Vicente
• Format: Article
• Language: English
• Subjects: Electrochemical storage; Energy storage system; Green energy; Hydrogen; Redox flow battery; Sustainability
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2021.230233

The development of clean, renewable, and affordable energy sources such as wind or sun has become a necessity for a sustainable energy society. Consequently, it is highly required the development of energy storage systems capable of efficiently storing the energy generated by these intermittent sources. In recent years, hydrogen-based technologies have emerged as a way of mitigating the environmental footprint left by the fossil fuels-based ones. In this paper we report new insights into the performance of an environmentally friendly Acid-Base Electrochemical Flow Battery (ABEFB), using an electrolyte consisting of high NaCl concentration. Energy is obtained from the neutralization of two acid and alkaline solutions through hydrogen evolution and oxidation reactions. Different parameters such as the nature of the cationic membrane and the electrolyte concentration have been systematically evaluated. Under optimal conditions, this battery can provide a maximum power density of about 73.5 W m-2 at 215 A m−2, a coulombic efficiency of around 80%, and a round-trip efficiency of 52%. •An acid-base electrochemical flow battery with optimized core elements is presented.•The battery provides a power density of 106 W m−2 and a faradaic efficiency of 80%.•Coulombic efficiencies strongly depend on membrane thickness and H+/Na+ ratio.•Mixing the posilyte and negalyte is a strategy to rebalance the battery.