Combining the Best of Solid-State and Liquid-State in a New Liquid-Metal BatteryJuly 09, 2020 by Gary Elinoff
Researchers at the University of Texas have developed a liquid metal battery that can operate at 20°C.
Most of today’s current liquid metal batteries must be kept at temperatures of 240℃ and above. The new development opens many possibilities, including improved utility-scale energy storage. Researchers at The University of Texas (UT) have recently developed a new type of battery that combines the many benefits of existing options while eliminating their key shortcomings and saving energy.
Solid-state batteries, such as solid-state lithium-ion batteries (LiB), offer a high energy storage capacity. However, they are subject to degradation over time and lose efficiency. Liquid metal batteries, on the other hand, are stable over time.
They also stand up to far more charge-recharge cycles than do LiBs, and they are more flexible in the manner in which they can deliver energy. But, they suffer from the enormously taxing disadvantage of needing to be maintained at a temperature of 240℃, which is necessary to keep their electrodes in a liquid state.
With its ability to operate at what amounts to room temperature, the UT battery represents a major breakthrough in liquid metal batteries. UT post-doctoral researcher and lead author Yu Din summed up the endeavor in a paper published in the journal Advanced Materials. As he describes it, “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.”
The liquid metal battery operates at room temperature. Image credited to the University of Texas
The Anatomy of a Room-Temperature Liquid-Metal Battery
The battery is comprised of an anode made of a sodium-potassium alloy as the anode, while a gallium-based alloy forms the cathode. Researchers state that it may be possible to build a battery that can operate at temperatures even lower than 68°F through the use of different materials.
As with all liquid metal batteries, the composition of cathode, anode, and electrolyte must be of materials that are immiscible with each other, and of different densities. This obviates the need for separating barriers. The new UT battery holds the promise of greater energy capacity than today’s lithium-ion batteries, which are presently the backbone of most personal electronics. Most importantly, the researchers claim it can be recharged several times faster than an LiB, a major advantage for consumer devices.
Because the battery is comprised of liquid components, the battery can easily be scaled up or down to accommodate varied power specifications. This adaptability opens the potential of the new energy device powering anything. This includes everything from tiny mobile devices to multi-megawatt storage for renewable energy plants.
The researchers have stated that the utilization of other materials might further improve the new battery. Hopefully, gallium will be one of the materials that can be replaced, because gallium is rather expensive. Additionally, because gallium, in the form of gallium nitride (GaN), makes possible a whole new semiconductor genre that is rapidly replacing silicon in high-power applications, the price is likely to rise higher yet.