Researchers in the US have built the first liquid metal battery that operates at room temperature.
The team at the Cockrell School of Engineering at The University of Texas at Austin used gallium, which is liquid at room temperature, as the cathode. The battery includes a sodium-potassium alloy as the anode and a gallium-based alloy as the cathode with an energy density of 181Wh/l. This compares to an energy density of 670Wh/l for lithium ion, but the advantage is that the battery call can easily be scaled for different power requirements.
This represents a major change, because current liquid metal battery cells must be kept at temperatures above 240 ºC. The room temperature metal battery promises more power than today’s lithium-ion batteries. It can charge and deliver energy several times faster, the researchers said. They say it may be possible to create a battery with even lower melting points using different materials as gallium is expensive.
“This battery can provide all the benefits of both solid- and liquid-state — including more energy, increased stability and flexibility — without the respective drawbacks, while also saving energy,” said Yu Ding, a postdoctoral researcher in associate professor Guihua Yu’s research group in the Walker Department of Mechanical Engineering.
The liquid elements mean the battery can be scaled up or down easily, depending on the power needed in the same way as a flow battery. The bigger the battery, the more power it can deliver.
“We are excited to see that liquid metal could provide a promising alternative to replace conventional electrodes,” Professor Yu said. “Given the high energy and power density demonstrated, this innovative cell could be potentially implemented for both smart grid and wearable electronics.”
However, gallium remains an expensive material. Finding alternative materials that can deliver the same performance while reducing the cost of production remains a key challenge.
The next step to increasing the power of the room-temperature battery comes in improving the