By Ellie Gabel
A common household ingredient might hold the key to a more sustainable future. Researchers from Arizona State University have found that adding sodium to a lithium-ion (li-ion) battery — the main energy source for electric cars, cell phones and computers — made for a stable battery that performed just as well as its pure counterparts. Sodium is easy to extract from salt and could reduce the world’s dependence on lithium, a dwindling resource.
Why Aren’t Lithium-Ion Batteries Sustainable?
Many people tout electric vehicles (EVs) as 100% eco-friendly alternatives to internal combustion engine cars. However, the truth is that the lithium-ion batteries powering them have a long way to go in the sustainability department. Here are the main areas in need of improvement.
In the U.S., only about 5% of li-ion batteries — from cars, cell phones, computers and other electronics — get recycled. The rest go to the landfill. Of the 5% that get recycled, workers extract an even smaller percentage of lithium from the crushed batteries. They mainly retrieve the nickel, cobalt, copper and plastic from them.
2. Water Use
Most of the world’s lithium comes from the aptly-named Lithium Triangle, an area encompassing parts of Argentina, Bolivia and Chile. The Lithium Triangle sits within a desert. As if the landscape wasn’t dry enough, many of the people living in the area are experiencing record-breaking droughts, so water usage is a huge point of contention.
Lithium extraction requires an enormous amount of water. It takes almost two million liters of water to extract a single ton of the metal, further straining the already drought-stressed communities and ecosystems nearby.
3. Dwindling Supply
The growing demand for electric vehicles is wonderful news for the climate. At the same time, it means lithium miners have had to ramp up production even more to try and keep pace with automakers’ needs. Experts predict demand for the metal will outpace supply by 2025, with an 846,575-ton deficit by the end of the decade.
While lithium is limited, the Earth has no shortage of sodium chloride, also known as table salt. Every continent has access to it via the ocean, and many countries have large salt deposits on land as well. It’s very cheap and easy to obtain — so abundant, in fact, that people often carve it into lamps or dishes.
Electrolysis — passing an electric current through a substance dissolved in water — breaks salt into its two components, sodium and chlorine. Sodium is a soft, silvery metal that looks a lot like lithium.
In 2023, scientists at Arizona State University created a battery from 90% lithium and 10% sodium. They incorporated the sodium into the battery’s cathode, which reacts with the anode to release energy. The team found the battery was just as efficient as a 100% lithium battery. They even predicted that a 20% sodium battery would perform equally well.
The Lawrence Berkeley National Laboratory is also working on a salt-based cathode. In 2022, a team of researchers from the California-based institute launched the DRX Consortium to study disordered rock salt (DRX), a promising battery ingredient.
Disordered rock salt’s cubic crystal structure makes it very stable. If scientists can figure out a way to integrate it into cathodes, they could create lithium-ion batteries with much more energy per weight than current batteries. In other words, the batteries wouldn’t be as heavy, leading to lighter electric vehicles and electronics.
How Salt Could Be a Game Changer
Replacing even just a tenth of the lithium in a battery would lead to enormous cost savings. It would also drastically reduce the amount of water needed for lithium mining, making more of it available for people and wildlife to drink. More countries could participate in the battery industry by supplying their own sodium for manufacturing.
Cheaper, more environmentally friendly batteries would ultimately lower the cost of electric vehicles and make them more appealing to eco-conscious drivers. Lighter-weight batteries could power EVs for longer and improve their driving ranges. That could convince drivers suffering from range anxiety to make the switch to an electric vehicle.
Other Ways to Make Greener Li-Ion Batteries
In addition to creating batteries with new materials, there are several other ways the lithium industry could become more sustainable.
The first is recycling. Governments need to invest more heavily in building recycling plants to handle lithium-ion batteries — and to fully extract the lithium from them. Standardizing the batteries from electronics and EVs will make it much easier for recycling plant workers and machines to pick them apart. By reusing the lithium already in circulation, the world will be less reliant on mining for raw materials.
Engineers are also working on developing new lithium extraction techniques. One method, direct lithium extraction, uses very little water. Other methods use reusable ion exchange beads or underground steam to retrieve the metal from briny water.
When lithium mining companies do need to use a lot of water, they have a moral obligation to inform the surrounding community long before the process starts. They should also supply fresh drinking water to any people they would otherwise impact.
Powering a Cleaner Future
With the world going electric, lithium has stepped into the spotlight — and many people are realizing, for the first time, just how far the lithium industry needs to go to become environmentally and socially responsible.
Thankfully, breakthroughs in engineering offer hope for new, greener batteries that will use less lithium than current models. Coupled with improvements in recycling and mining, the rare metal could continue powering our world without damaging it in the process.
About the Author
Ellie Gabel is the sciences editor at Revolutionized, where she specializes in astronomy, environmental science, and innovative technologies.