New Liquid-Metal Battery Provides High Power at Room Temperature
Edis Osmanbasic posted on September 11, 2020 |
New research combines the best of both solid-state and liquid-state batteries.
(Image courtesy of University of Texas.)
(Image courtesy of University of Texas.)

A new type of a liquid-metal battery has the potential to provide more power than lithium-ion batteries while maintaining room temperature. Developed at the University of Texas at Austin (UT), the research was published in the journal Advanced Materials, where the innovation was dubbed the first "room-temperature, all-liquid metal battery."  

The majority of batteries are composed of solid electrodes, such as lithium-ion batteries for portable electronics, or liquid electrodes, such as flow batteries for smart grids. Both types have advantages and disadvantages. Solid-state batteries have substantial energy storage capacity; however, they are susceptible to degradation and becoming less efficient. Liquid-state batteries do not degrade over time, but they require considerable resources to heat the electrodes and keep them molten.

The UT researchers combined the strengths of both solid-state and liquid-state batteries in the new room-temperature battery, simultaneously circumventing their disadvantages. The new battery type has more energy capacity, stability, and flexibility, as well as other advantages of liquid metals shown below: 

Liquid metals properties suitable for battery technology. (Source: [1].)
Liquid metals properties suitable for battery technology. (Source: [1].)
Liquid metal batteries have been considered as potential electrochemical systems for stationary energy storage, but they require temperatures above 240 °C to maintain the molten state of the metallic electrodes. The new research achieves a room-temperature liquid metal battery employing sodium-potassium (Na–K) alloy anode and gallium (Ga)‐based alloy cathodes. Its nontoxic Ga alloys maintain high environmental standards when compared to the lead (Pb)‐ and mercury (Hg)‐based liquid metal electrodes. 

The new type of liquid electrode/electrolyte interphase will inevitably have a significant role in stabilizing the redox chemistry and regulating charge carriers. Because of the improved wetting and stabilized interfacial chemistry, the liquid metal batteries provide stable cycling performance and small self‐discharge. 

The researchers also revealed the metallic electrodes in the new battery can remain liquefied at the lowest operating temperature recorded for a liquid-metal battery, which is only 20 degrees Celsius (68 degrees Fahrenheit). 

“With facile cell fabrication, simplified battery structures, high safety, and low maintenance costs, room‐temperature liquid metal batteries not only show great prospects for widespread applications but also offer a pathway toward developing innovative energy‐storage devices beyond conventional solid‐state batteries or high‐temperature batteries,” said researcher Yu Ding. 

“We are excited to see that liquid metal could provide a promising alternative to replace conventional electrodes,” explained researcher Guihua Yu. "Given the high energy and power density demonstrated, this innovative cell could be potentially implemented for both smart grid and wearable electronics.” 

This new room-temperature battery has the potential for more power than the most commonly used lithium-ion batteries, with the additional advantages of faster charging and energy delivering properties.

[1] Next-Generation Liquid Metal Batteries Based on the Chemistry of Fusible Alloys, Yu Ding, Xuelin Guo, and Guihua Yu, ACS Central Science 2020 6 (8), 1355-1366. DOI: 10.1021/acscentsci.0c00749

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