Published: March 8, 2017 By

University of Colorado Boulder engineers have received a $3 million grant from the U.S. Department of Energy (DOE) to develop better membranes for more efficient and cost-effective large-scale battery technology as a means of storing energy generated by methods such as wind and solar.

The research project, led by Richard Noble, Douglas Gin and Hans Funke of CU Boulder’s Department of Chemical and Biological Engineering, will focus on improving the sophisticated membranes hidden inside powerful flow batteries. Unlike small, self-contained consumer batteries (AAAs, for example), flow batteries use external tanks to store the chemicals needed for an electrical reaction. The chemicals are commonly separated by a semi-permeable membrane.

Historically, a key challenge of flow batteries has been perfecting the efficiency of their delicate membrane, which allows negatively-charged chloride ions to pass through but rejects unwanted ions. The membrane’s tiny, uniform pores are less than one nanometer wide, smaller than a single DNA molecule.

Current flow batteries use a variety of chemical solutions, but all-iron versions are considered attractive because they can use one of Earth’s cheapest and most abundant materials.  The three-year grant from the DOE’s Advanced Research Projects Agency-Energy (ARPA-E) will include partners from the University of California San Diego and ESS Tech, Inc., a Portland, Oregon, company that specializes in all-iron flow batteries.

If researchers are successful in improving on the all-iron flow batteries, the outcome could be a highly efficient flow batter that costs less than $100 per kilowatt-hour — a significant cost improvement from current flow batteries on the market.  Such batteries would offer a safe, low-maintenance solution for large-scale electrical energy storage — including the intermittent energy generated from wind and solar — for business or military use.

Gin and Noble have been working on nanoporous membrane technology for 15 years across a variety of applications, including water desalination and improving biohazard suits that can protect against chemical warfare agents.

Gin said the team is excited to retool the membrane technology invented at CU Boulder for a new, more sophisticated application.

“Now we’re in that phase where we don’t have to make huge quantum leaps,” said Gin. “Small alterations with a system that’s fairly mature can start making a difference right away.”

a wind turbine

Photo: Tom Corser / Wikipedia