The battery uses one electrode made of molten lithium and another of lead and antimony to store energy at a temperature over 200°C lower than earlier liquid metal designs.
It has an operating efficiency of about 70% with the capacity to retain 85% of its efficiency after a decade of daily use.
The researchers had earlier used magnesium and antimony layers to form the battery’s electrodes, which required an operating temperature of 700°C.
The new formulation has reduced the temperature to between 450°C and 500 C and cut the production cost of the battery.
The researchers identified that the antimony provided a high operating voltage while the lead gave a low melting point, and the combination of both the metals allowed the battery to operate at a lower temperature.
MIT John F. Elliott Professor of Materials Chemistry Donald Sadoway said: "We hoped [the characteristics of the two metals] would be nonlinear.
"They proved to be [nonlinear], but beyond our imagination. There was no decline in the voltage. That was a stunner for us."
The US Department of Energy’s Advanced Research Projects Agency-Energy and French energy firm Total have supported the research.
Sadoway and colleagues have started a company to produce electrical-grid-scale liquid batteries, whose layers of molten material automatically separate due to their varying densities.
The research team plans to continue to identify for other combinations of metals that could offer even lower-temperature, less costs and higher-performance systems.
Sadoway said: "Now we understand that liquid metals bond in ways that we didn’t understand before."
Image: A physical model of the liquid metal battery at room temperature, in a glass container. Photo: Courtesy of Felice Frankel.
