A Harvard University team came up with a way to drive down the cost of flow battery technology, which is capable of storing energy on large scales – within an electrical power grid, for example. Grid-scale storage for renewables could be a game-changer – making wind and solar more economical and reliable.
While flow battery designs are suited to storing large amounts of energy cheaply, they have previously relied on chemicals that are expensive or difficult to maintain, driving up costs.
Most previous flow batteries have chemistries based on metals. Vanadium is used in the most commercially advanced flow battery technology, but its cost is relatively high. Other variants contain precious metal catalysts such as platinum.
The researchers say their new battery already performs as well as vanadium flow batteries, but uses no precious metal catalyst and has an underlying chemistry that is metal-free, instead relying on naturally abundant, more affordable chemicals called quinones.
These water-soluble compounds are organic (carbon-based) and are similar to chemicals that store energy in plants and animals.
"These molecules are cheap and they’re in all green vegetables, as well as crude oil," said co-author Michael Aziz from the Harvard School of Engineering and Applied Sciences (SEAS) in Cambridge, Massachusetts.
The mismatch between the availability of intermittent wind or sunshine and the changing demand for grid electricity is one of the main obstacles to boosting the fraction of energy that comes from renewable sources.