University of Illinois

University of California

University of Michigan

Etienne Chénard

Jeffrey S Moore

Sean Emerson Doris

Brett Anthony Helms

Melanie S Sanford

Peter David Frischmann

Ashleigh L Ward

Nagarjuna Gavvalapalli

Rachel Brooner

Christo Slavov Sevov

Intermittent energy sources, including solar and wind, require scalable, low-cost, multi-hour energy storage solutions to be effectively incorporated into the grid. Redox-flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox-active species across the battery's membrane. Here we show that active-species crossover can be arrested by scaling the membrane's pore size to molecular dimensions and in turn increasing the size of the active material to be above the membrane's pore-size exclusion limit. When oligomeric redox-active organic molecules were paired with microporous polymer membranes, the rate of active-material crossover was either completely blocked or slowed more than 9,000-fold compared to traditional separators at minimal cost to ionic conductivity. In the case of the latter, this corresponds to an absolute rate of ROM crossover of less than 3 &#x3bc;mol cmday(for a 1.0 M concentration gradient), which exceeds performance targets recently set forth by the battery industry. This strategy was generalizable to both high and low-potential ROMs in a variety of electrolytes, highlighting the importance of macromolecular design in implementing next-generation redox-flow batteries.

Redox-flow batteries employing oligomeric organic active materials and size-selective microporous polymer membranes

Organic anolyte materials for redox flow batteries and redox flow batteries containing organic anolyte materials are disclosed.

Organic anolyte materials for flow batteries

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Urbana, IL, United States of America

Etienne Chénard