Eutectic Mixing As a Knob for Next-Generation Flow Batteries

Abstract

Flow batteries can offer scalability, long cycle-life, and power-to-energy tunability, however, they have low energy density. An under-explored “knob” for increasing the energy density of flow batteries is eutectic mixing for the depression of melting points. This knob could enable high energy-density flow batteries by achieving solvent-free electrolytes. We demonstrate the ability of eutectic mixing to decrease melting points in the case of n-component mixtures of benzoquinone derivatives, which are redox-active molecules. Predicting the properties of mixtures of more than two components is not commonly done, but we show that, in this case, a regular solution model has predictive power for finding the eutectic melting temperatures and compositions for mixtures of multiple components.