Scientists at Argonne National Laboratory’s innovation hub have identified two types of battery they believe can become the technology of the future.
The Joint Center for Energy Storage Research (JCESR) has chosen a redox flow battery and a lithium-sulfur battery for further exploration as it moves into the final year of a five-year charter.
JCESR believes both prototypes will reach $100/kWh at the pack level by the end of 2017.
Lithium-sulfur is seen as a potential replacement for lithium-ion because, having already reached 300wh/kg, its theoretical energy density could be as much as ten times that.
JCSER’s battery uses a lithium metal anode protected by a graphene oxide membrane, and a polymer-composite sulfur cathode.
Key to JCSER’s prototype success, aimed at the electric vehicle market, will be achieving a very low ratio of electrolyte to sulfur content, said George Crabtree, an Argonne National Laboratory Distinguished Fellow, and director of the JCESR.
The scientists aim to develop an electrolyte that limits reactions of the polysulfides that form during cycling; use binders in the sulfur cathode to trap polysulfides before they dissolve in the electrolyte; and create membranes that stop the movement of polysulfides from the cathode to the anode.
Crabtree said: “We believe that the final embodiment of the lithium-sulfur prototype will require a combination of these features to meet the JCESR cost and performance targets.”
The flow battery, for grid applications, uses an aqueous sulfur anode and oxygen cathode. Its organic molecules will be linked together in oligomers of up to 10 molecules, polymers of up to 1,000 molecules and colloidal particles of a million to a billion molecules.
Full cell testing of each of the concepts is underway, and proof-of-principle prototypes are due to be evaluated within the next year.
Crabtree said: “Our vision was bold: high-performance, low-cost electricity storage that would lead to widespread deployment of electric vehicles and transformation of the electricity grid with renewable generation and distributed energy resources.”