Electrochemical study of redox couples in heavy water for redox flow battery applications | Poster Board #390

Aqueous redox flow batteries are promising approach to store solar and wind generated electricity because of their safe and inexpensive nature and adjustable storage capacity by electrolyte volume. However, their largest disadvantage is the narrow electrochemical stability window of H₂O due to H₂ and O₂ evolution (thermodynamically, 1.23 V). Recently, it has been reported that this window was expanded to 3.3 V with 1 m Na₂SO₄ in D₂O thanks to the deuterium isotope effect. In order to utilize the expanded electrochemical stability window of D₂O, we have been examining how D₂O affects the redox potentials and reversibility of redox couples. Our reseach shows variations of D₂O effect on redox behavior of redox couples, which are: no effect on [Fe(CN)₆]^3+/2+ and positive shift of redox potentials on Fe(H₂O)₆^3+/2+. Our goal is to examine the effects of D₂O on the electrochemical behavior of organic redox couples, such as quinone and quinoxaline, because we can reduce batteries' relience on metals by employing nonmetal redox species. Organic redox process often involves H⁺ transfer, therefore, the D₂O effects are highly expected.