(Press-News.org) ALBUQUERQUE, N.M. -- Researchers at Sandia National Laboratories have designed a new class of molten sodium batteries for grid-scale energy storage. The new battery design was shared in a paper published today in the scientific journal Cell Reports Physical Science.
Molten sodium batteries have been used for many years to store energy from renewable sources, such as solar panels and wind turbines. However, commercially available molten sodium batteries, called sodium-sulfur batteries, typically operate at 520-660 degrees Fahrenheit. Sandia's new molten sodium-iodide battery operates at a much cooler 230 degrees Fahrenheit instead.
"We've been working to bring the operating temperature of molten sodium batteries down as low as physically possible," said Leo Small, the lead researcher on the project. "There's a whole cascading cost savings that comes along with lowering the battery temperature. You can use less expensive materials. The batteries need less insulation and the wiring that connects all the batteries can be a lot thinner."
However, the battery chemistry that works at 550 degrees doesn't work at 230 degrees, he added. Among the major innovations that allowed this lower operating temperature was the development of what he calls a catholyte. A catholyte is a liquid mixture of two salts, in this case, sodium iodide and gallium chloride.
Basics of building better batteries
A basic lead-acid battery, commonly used as a car ignition battery, has a lead plate and a lead dioxide plate with a sulfuric acid electrolyte in the middle. As energy is discharged from the battery, the lead plate reacts with sulfuric acid to form lead sulfate and electrons. These electrons start the car and return to the other side of the battery, where the lead dioxide plate uses the electrons and sulfuric acid to form lead sulfate and water. For the new molten sodium battery, the lead plate is replaced by liquid sodium metal, and the lead dioxide plate is replaced by a liquid mixture of sodium iodide and a small amount of gallium chloride, said Erik Spoerke, a materials scientist who has been working on molten sodium batteries for more than a decade.
When energy is discharged from the new battery, the sodium metal produces sodium ions and electrons. On the other side, the electrons turn iodine into iodide ions. The sodium ions move across a separator to the other side where they react with the iodide ions to form molten sodium iodide salt. Instead of a sulfuric acid electrolyte, the middle of the battery is a special ceramic separator that allows only sodium ions to move from side to side, nothing else.
"In our system, unlike a lithium ion battery, everything is liquid on the two sides," Spoerke said. "That means we don't have to deal with issues like the material undergoing complex phase changes or falling apart; it's all liquid. Basically, these liquid-based batteries don't have as limited a lifetime as many other batteries."
In fact, commercial molten sodium batteries have lifetimes of 10-15 years, significantly longer than standard lead-acid batteries or lithium ion batteries.
Long-lasting batteries that are safer
Sandia's small, lab-scale sodium-iodide battery was tested for eight months inside an oven. Martha Gross, a postdoctoral researcher who has worked on the laboratory tests for the past two years, conducted experiments charging and discharging the battery more than 400 times over those eight months.
Because of the COVID-19 pandemic, they had to pause the experiment for a month and let the molten sodium and the catholyte cool down to room temperature and freeze, she said. Gross was pleased that after warming the battery up, it still worked.
This means that if a large-scale energy disruption were to occur, like what occurred in Texas in February, the sodium-iodide batteries could be used, and then allowed to cool until frozen. Once the disruption was over, they could be warmed up, recharged and returned to normal operation without a lengthy or costly start-up process, and without degradation of the battery's internal chemistry, Spoerke added.
Sodium-iodide batteries are also safer. Spoerke said, "A lithium ion battery catches on fire when there is a failure inside the battery, leading to runaway overheating of the battery. We've proven that cannot happen with our battery chemistry. Our battery, if you were to take the ceramic separator out, and allow the sodium metal to mix with the salts, nothing happens. Certainly, the battery stops working, but there's no violent chemical reaction or fire."
If an outside fire engulfs a sodium-iodide battery, it is likely the battery will crack and fail, but it shouldn't add fuel to the fire or cause a sodium fire, Small added.
Additionally, at 3.6 volts, the new sodium-iodide battery has a 40% higher operating voltage than a commercial molten sodium battery. This voltage leads to higher energy density, and that means that potential future batteries made with this chemistry would need fewer cells, fewer connections between cells and an overall lower unit cost to store the same amount of electricity, Small said.
"We were really excited about how much energy we could potentially cram into the system because of the new catholyte we're reporting in this paper," Gross added. "Molten sodium batteries have existed for decades, and they're all over the globe, but no one ever talks about them. So, being able to lower the temperature and come back with some numbers and say, 'this is a really, really viable system' is pretty neat."
The future of sodium-iodide batteries
The next step for the sodium-iodide battery project is to continue to tune and refine the catholyte chemistry to replace the gallium chloride component, Small said. Gallium chloride is very expensive, more than 100 times as expensive as table salt.
The team is also working on various engineering tweaks to get the battery to charge and discharge faster and more fully, Spoerke added. One previously identified modification to speed up the battery charging was to coat the molten sodium side of the ceramic separator with a thin layer of tin.
Spoerke added that it would likely take five to 10 years to get sodium-iodide batteries to market, with most of the remaining challenges being commercialization challenges, rather than technical challenges.
"This is the first demonstration of long-term, stable cycling of a low-temperature molten-sodium battery," Spoerke said. "The magic of what we've put together is that we've identified salt chemistry and electrochemistry that allow us to operate effectively at 230 degrees Fahrenheit. This low-temperature sodium-iodide configuration is sort of a reinvention of what it means to have a molten sodium battery."
The development of the new sodium battery was supported by the Department of Energy's Office of Electricity Energy Storage Program.
INFORMATION:
Scientists have developed a new way to model and map the health of coral reef ecosystems using data collected on the Khaled bin Sultan Living Oceans Foundation's Global Reef Expedition. This innovative method, presented today at the International Coral Reef Symposium (ICRS), can determine which natural and anthropogenic factors are most likely to lead to persistently vibrant coral and fish communities. Their findings can help scientists identify the reefs most likely to survive in a changing world.
The new models are a first step in being able to produce maps of global coral reef resilience.
To create these models, scientist Anna Bakker needed a lot of data on coral reefs from ...
Drugs must be safe not just for the patients; in the case of pregnant patients, drugs must also be safe for the unborn children still in the womb. Therefore, at an early stage in the development of new medicines, candidate substances are tested in the Petri dish on embryonic stem cells from mouse cell lines. This is to avoid that an embryo-damaging effect would only be noticed at a later stage during tests with pregnant mice.
However, these cell culture tests are a highly simplified version of what takes place in the uterus. Researchers just add the test material to a culture of embryonic stem cells in a Petri dish, and can identify substances that have a direct adverse effect on embryonic cells. By contrast, in the body of a pregnant woman, active pharmaceutical ...
New Rochelle, NY, July 21, 2021-- Evaluating the efficacy of novel therapies requires the ability to monitor wound progression accurately and reproducibly over time. Researchers have proposed a new scoring system for wound healing in mice based on parameters in each phase of healing, as described in an article in the peer-reviewed journal Stem Cells and Development. Click here to read the article for free through August 21, 2021.
The parameters include re-epithelization, epithelial thickness index, keratinization, granulation tissue thickness, remodeling, and the scar elevation index. The parameters can be assessed using either Hematoxylin & Eosin or ...
By José Tadeu Arantes | Agência FAPESP – Gluten is a protein complex found in cereals such as wheat, rye and barley. It is responsible for the elastic texture of dough so that loaves and rolls can be baked into different shapes while remaining flexible and crusty. It also lengthens the shelf life of bread at room temperature, when associated with preservatives.
Gluten intolerance, however, has become a global epidemic, and gluten-free products are increasingly popular. The problem is that most of those available on the market are far from corresponding to consumers’ expectations in terms of appearance, aroma, flavor and durability. A research line focusing on ways to enhance gluten-free products is being pursued ...
No one wants bad breath -- not when visiting friends and family, at a job interview, and especially not on a first date. Smelly breath can make things awkward, but it also is a natural warning sign, indicating that serious dental issues are occurring. Now, researchers reporting in ACS Nano have constructed a portable, thumb-sized device that diagnoses bad breath by quickly "sniffing" exhalations for the gas that makes it stinky -- hydrogen sulfide.
Because most people can't smell their own breath, they need to ask someone else, which can be embarrassing and awkward. Some devices measure small amounts of stinky hydrogen sulfide, but they require exhaled air to be collected and tested on expensive instruments in a lab, which is not feasible ...
Safe and effective vaccines offer hope for an end to the COVID-19 pandemic. However, the possible emergence of vaccine-resistant SARS-CoV-2 variants, as well as novel coronaviruses, make finding treatments that work against all coronaviruses as important as ever. Now, researchers reporting in ACS' Journal of Proteome Research have analyzed viral proteins across 27 coronavirus species and thousands of samples from COVID-19 patients, identifying highly conserved sequences that could make the best drug targets.
Drugs often bind inside "pockets" on proteins that hold the drug snugly, causing it to interfere with the protein's function. Scientists can identify potential drug-binding pockets from the 3D structures of viral proteins. ...
WASHINGTON, July 21, 2021 -- As the Summer Olympics draw near, the world will shift its focus to photo finishes and races determined by mere fractions of a second. Obtaining such split-second measurements relies on faultlessly rounding a raw time recorded by a stopwatch or electronic timing system to a submitted time.
Researchers at the University of Surrey found certain stopwatches commit rounding errors when converting raw times to final submitted times. In American Journal of Physics, by AIP Publishing, David Faux and Janet Godolphin outline a series of computer simulations based on procedures for converting raw race times for display.
Faux was inspired when he encountered ...
ITHACA, N.Y. - Cornell researchers have developed nanostructures that enable record-breaking conversion of laser pulses into high-harmonic generation, paving the way for new scientific tools for high-resolution imaging and studying physical processes that occur at the scale of an attosecond - one quintillionth of a second.
High-harmonic generation has long been used to merge photons from a pulsing laser into one, ultrashort photon with much higher energy, producing extreme ultraviolet light and X-rays used for a variety of scientific purposes. Traditionally, gases have been used as sources of harmonics, but a research team led by Gennady Shvets, professor of applied and engineering physics ...
Researchers at Weill Cornell Medicine and NewYork-Presbyterian in New York have discovered that injecting mice with pulmonary endothelial cells--the cells that line the walls of blood vessels in the lung--can reverse the symptoms of emphysema. The study, which will be published July 21 in the Journal of Experimental Medicine (JEM), may lead to new treatments for chronic obstructive pulmonary disease (COPD), an inflammatory lung disease associated with smoking that is thought to be the third leading cause of death worldwide.
Emphysema is one of the characteristic features ...
Wearable devices can detect people's stress, according to new Washington State University research, opening potential new interventions for people with addictions.
In a paper published today, July 21, in the END ...
