AUSTIN, Texas — A sodium-sulfur battery created by engineers at The College of Texas at Austin solves one particular of the largest hurdles that has held again the know-how as a commercially feasible different to the ubiquitous lithium-ion batteries that power almost everything from smartphones to electric vehicles.
Sodium and sulfur stand out as interesting supplies for long term battery production since they are cheaper and extra broadly offered than materials these kinds of as lithium and cobalt, which also have environmental and human rights worries. Simply because of this, researchers have labored for the past two many years to make place-temperature, sodium-centered batteries practical.
“I simply call it a desire technology for the reason that sodium and sulfur are plentiful, environmentally benign, and the most affordable charge you imagine of,” reported Arumugam Manthiram, director of UT’s Texas Resources Institute and professor in the Walker Office of Mechanical Engineering. “With expanded electrification and elevated require for renewable energy storage going ahead, price and affordability will be the one dominant factor.”
In one particular of two latest sodium battery improvements from UT Austin, the researchers tweaked the makeup of the electrolyte, the liquid that facilitates movement of ions back and forth involving the cathode and anode to encourage charging and discharging of the batteries. They attacked the popular challenge in sodium batteries of the expansion of needle-like constructions, called dendrites, on the anode that can trigger the battery to quickly degrade, short circuit, and even catch fireplace or explode.
The researchers posted their findings in a modern paper in the Journal of the American Chemical Modern society.
In previous electrolytes for sodium-sulfur batteries, the intermediate compounds fashioned from sulfur would dissolve in the liquid electrolyte and migrate involving the two electrodes inside of the battery. This dynamic, recognised as shuttling, can lead to product loss, degradation of components, and dendrite development.
The scientists created an electrolyte that prevents the sulfur from dissolving and hence solves the shuttling and dendrite complications. That allows a longer daily life cycle for the battery, demonstrating a secure functionality about 300 cost-discharge cycles.
“When you place a large amount of sugar in drinking water, it gets syrupy. Not almost everything is dissolved absent,” stated Amruth Bhargav, a doctoral scholar in Manthiram’s lab. “Some issues are 50 percent linked and half dissolved. In a battery, we want this in a 50 %-dissolved point out.”
The new battery electrolyte was designed in a identical vein by diluting a concentrated salt resolution with an inert, nonparticipating solvent, which preserves the “half-dissolved” condition. The researchers discovered that this kind of an electrolyte helps prevent the unwelcome reactions at the electrodes and hence prolongs the everyday living of the battery.
The value of lithium has skyrocketed during the earlier yr, underscoring the require for choices. Lithium mining has been criticized for its environmental impacts, like large groundwater use, soil and drinking water air pollution, and carbon emissions. By comparison, sodium is readily available in the ocean, more cost-effective, and far more environmentally friendly.
Lithium-ion batteries typically also use cobalt, which is pricey and mined mostly in Africa’s Democratic Republic of the Congo, exactly where it has major impacts on human overall health and the natural environment. Last year, Manthiram demonstrated a cobalt-cost-free lithium-ion battery.
The researchers program to make on their breakthrough by screening it with larger batteries to see irrespective of whether it can be relevant to systems, this kind of as electric autos and storage of renewable assets these types of as wind and photo voltaic.
Other authors on the paper consist of Texas Elements Institute postdoctoral fellows Jiarui He and Woochul Shin. The research was supported by grants from the U.S. Division of Energy’s Workplace of Essential Energy Sciences, Division of Materials Science and Engineering.