Innovation in Stationary Electricity Storage: the Liquid Metal Battery

Donald Sadoway, John F. Elliott Professor of Materials Chemistry, Department of Materials Science and Engineering, Massachusetts Institute of Technology

Hopeman 224

Massive electricity storage would offer huge benefits to today’s grid, reducing price volatility, improving stability against loss of power, increasing utilization of generation assets by enabling us to design towards average demand instead of peak demand, and deferring the costs of upgrading existing transmission lines. When it comes to tomorrow’s grid, storage is critical to widespread integration of renewables, i.e., solar and wind, which due to their inherent intermittency present challenges for contribution to base load. Comprising two liquid metals and a molten salt electrolyte, the liquid metal battery has been invented to offer colossal current capability and long service lifetime at very low cost, i.e., the price point of the electricity market. The round-trip efficiency of these batteries is greater than 75% with a duty cycle of 4 h discharge (C/4). Fade rates of 0.00009%/cycle have been measured which means retention of >99% of initial capacity after 10 years of daily cycling at full depth of discharge. There is much to be learned from the innovative process that led to the discovery of disruptive battery technology.