A Redox-Shuttled Electrochemical Method for Energy-Efficient Separation of Salt from Water

We present a novel electrochemical method for separating salt from water in a practical, energy-efficient manner: SUPER (ShUttle-Promoted Electrolyte Removal). SUPER combines elements from redox flow batteries and conventional electrodialysis: a redox shuttle in a four-chambered cell architecture drives ion motion at very low voltages and energy consumption without splitting water, uses no electrocatalysts, and can be salt-agnostic. As exemplified by NaCl, we demonstrate salt removal at a gravimetric specific energy consumption (SEC) as low as 0.046 kWh/kg NaCl transported, which is equivalent to producing water at drinkable salinity (