AUSTIN, Texas — A sodium-sulfur battery made by engineers at The University of Texas at Austin solves one particular of the most significant hurdles that has held back again the technological know-how as a commercially viable alternative to the ubiquitous lithium-ion batteries that energy everything from smartphones to electrical motor vehicles.
Sodium and sulfur stand out as captivating elements for future battery output because they are cheaper and much more greatly offered than materials these kinds of as lithium and cobalt, which also have environmental and human legal rights concerns. Since of this, researchers have labored for the past two many years to make home-temperature, sodium-based mostly batteries feasible.
“I connect with it a aspiration know-how due to the fact sodium and sulfur are considerable, environmentally benign, and the most affordable expense you imagine of,” reported Arumugam Manthiram, director of UT’s Texas Supplies Institute and professor in the Walker Section of Mechanical Engineering. “With expanded electrification and amplified want for renewable power storage likely forward, price tag and affordability will be the solitary dominant factor.”
In one of two the latest sodium battery advances from UT Austin, the researchers tweaked the makeup of the electrolyte, the liquid that facilitates motion of ions back again and forth in between the cathode and anode to encourage charging and discharging of the batteries. They attacked the typical problem in sodium batteries of the growth of needle-like constructions, called dendrites, on the anode that can result in the battery to quickly degrade, quick circuit, and even catch hearth or explode.
The researchers released their conclusions in a new paper in the Journal of the American Chemical Society.
In preceding electrolytes for sodium-sulfur batteries, the intermediate compounds shaped from sulfur would dissolve in the liquid electrolyte and migrate between the two electrodes in the battery. This dynamic, identified as shuttling, can lead to material decline, degradation of components, and dendrite development.
The scientists developed an electrolyte that stops the sulfur from dissolving and as a result solves the shuttling and dendrite challenges. That allows a for a longer time daily life cycle for the battery, displaying a steady effectiveness around 300 charge-discharge cycles.
“When you put a ton of sugar in h2o, it results in being syrupy. Not almost everything is dissolved away,” claimed Amruth Bhargav, a doctoral university student in Manthiram’s lab. “Some things are 50 percent connected and 50 % dissolved. In a battery, we want this in a 50 percent-dissolved state.”
The new battery electrolyte was created in a related vein by diluting a concentrated salt answer with an inert, nonparticipating solvent, which preserves the “half-dissolved” condition. The researchers found that these kinds of an electrolyte prevents the undesired reactions at the electrodes and therefore prolongs the existence of the battery.
The value of lithium has skyrocketed for the duration of the earlier yr, underscoring the need for options. Lithium mining has been criticized for its environmental impacts, including weighty groundwater use, soil and water air pollution, and carbon emissions. By comparison, sodium is accessible in the ocean, less costly, and more environmentally pleasant.
Lithium-ion batteries normally also use cobalt, which is expensive and mined typically in Africa’s Democratic Republic of the Congo, exactly where it has important impacts on human health and the atmosphere. Final calendar year, Manthiram shown a cobalt-absolutely free lithium-ion battery.
The scientists plan to make on their breakthrough by screening it with larger batteries to see whether it can be relevant to systems, these as electrical autos and storage of renewable assets these types of as wind and solar.
Other authors on the paper incorporate Texas Materials Institute postdoctoral fellows Jiarui He and Woochul Shin. The exploration was supported by grants from the U.S. Division of Energy’s Office of Primary Electrical power Sciences, Division of Materials Science and Engineering.