Room Temperature Liquid-Metal Battery Could Provide More Power Than Li-ionAugust 29, 2020 by Luke James
Texas researchers realize the strengths of both solid-state and liquid-state batteries in the first room-temperature liquid-metal battery.
Researchers at the Cockrell School of Engineering at the University of Texas at Austin have developed a new type of battery that they claim combines many of the benefits of both solid- and liquid-state batteries. These include more energy capacity, stability, and flexibility—without the drawbacks of both types of batteries.
Their research, recently published in the journal Advanced Materials, says this new battery is the first "room-temperature, all-liquid metal battery."
More Power Than Li-ion
Solid-state batteries and liquid-state batteries each have their respective strengths and trade-offs.
Although solid-state batteries feature significant energy storage capacity, they typically degrade and become less efficient over time. In contrast, a liquid-metal battery can deliver energy more efficiently and without the long-term decay seen in solid-state devices. However, they typically fall short when it comes to high-energy applications or require significant resources to heat the electrodes and keep them in a molten state.
Structure of the new liquid-metal battery. Image used courtesy of University of Texas at Austin
According to the University of Texas research team, the metallic electrodes in their battery can remain liquefied at temperatures of only 20 degrees Celsius, or 68 degrees Fahrenheit. To date, this is the lowest operating temperature recorded for a liquid-metal battery, which usually requires temperatures of 240 degrees Celsius or higher.
“We are excited to see that liquid metal could provide a promising alternative to replace conventional electrodes,” explains professor Guihua Yu. "Given the high energy and power density demonstrated, this innovative cell could be potentially implemented for both smart grid and wearable electronics.”
A Flexible and Scalable Battery
The room-temperature battery promises more power than the backbone of most of today’s personal electronic devices—lithium-ion batteries—and can charge and deliver energy several times faster.
The battery’s anode is made of a sodium-potassium alloy and a gallium-based alloy is used as the cathode. In their paper, the researchers acknowledge that it may be possible to create a battery with even lower melting points by using different materials, hinting to the potential for further research in this field.
Actual image of the battery. Image used courtesy of University of Texas at Austin
Since the battery is made of liquid components, it can easily be scaled up or down to meet power demands. The bigger the battery is, the more power it delivers. This flexibility enables the all-liquid battery to potentially power everything from simple consumer devices to high-level infrastructure in the renewable energy sector.
According to the team, the next step is to increase the battery’s power by improving its electrolytes. “Although our battery cannot compete with high-temperature, liquid-metal batteries at the current stage, better power capability is expected if advanced electrolytes are designed with high conductivity,” said Yu Ding, lead author of the paper.