Researchers at the University of Southern California looking to crack the renewable energy storage problem have developed a new version of a redox flow battery from inexpensive and readily-available materials.

Though there are huge lithium-ion battery installations from the likes of Tesla that can store energy harvested from renewables like wind and solar, they're not exactly cheap. The USC researchers looked to an existing design that stores energy in liquid form.

In the so-called redox flow battery, a positive chemical and a negative chemical are stored in separate tanks. The chemicals are pumped in and out of a chamber where they exchange ions across a membrane – flowing one way to charge and the other to discharge.

Though such systems have previously used expensive, dangerous and toxic vanadium and bromine dissolved in acid for their electrolytes in the past, we have seen recent designs that replace those with organic or more environment-friendly alternatives.