Despite the fact that clean energy solutions are a necessity, the reliance on cobalt mining from war-torn countries, and the relatively high price and rarity of both lithium and cobalt, is a stain on their sustainability record.
Researchers from Washington State University (WSU) and Pacific Northwest National Laboratory (PNNL) created a sodium-ion battery that works as efficiently as some commercial lithium-ion batteries.
The work paves the way for a more sustainable battery production that can meet the growing demand for electric vehicles and other battery technologies.
A sodium-ion battery that works as well as lithium-ion batteries
The team of researchers, led by Yuehe Lin, a professor in WSU's School of Mechanical and Materials Engineering, and Xiaolin Li, a senior research scientist at PNNL, worked to overcome one of the main issues with sodium-ion batteries in the past; namely, the fact that a layer of inactive sodium crystals builds up at the surface of the battery's cathode, stopping the flow of sodium ions and killing the battery.
In order to tackle the cathode problem, the team created a layered metal oxide cathode that included extra sodium ions, allowing for unimpeded electricity generation.
The findings, published in the journal ACS Energy Letters, show that their sodium-ion battery is able to deliver a capacity similar to some lithium-ion batteries and that, crucially, it could recharge successfully, keeping more than 80 percent of its charge after 1,000 cycles.
A sustainable alternative to lithium and cobalt
Lithium-ion batteries are ubiquitous in today's world as practically all of us carry one around in our smartphones and laptops. With the increasing demand and regulations in favor of electric vehicle production, their use will become even more widespread.
The problem is that they are made out of cobalt and lithium, two materials that are relatively rare, expensive, and often sourced from poor countries where miners work under terrible conditions.
Prices will only continue to go up as demand for electric vehicles and electricity storage rises, and Lithium might be too scarce to meet the growing demand. As recently as 2018, Tesla warned the U.S. government of impending shortages.
Sodium-ion batteries could solve this problem as they are made from cheap, abundant, and sustainable sodium from the Earth's oceans and crust.
The WSU and PNNL research "shed light on how we might develop future cobalt-free or low cobalt cathode materials in sodium-ion batteries as well as in other types of battery chemistries," Junhua Song, lead author on the paper and WSU Ph.D. graduate, said in a press release.
"If we can find viable alternatives to both lithium and cobalt, the sodium-ion battery could truly be competitive with lithium-ion batteries. And, that would be a game-changer," he added.
The next step to making this happen is further research and work into making a sodium-ion battery with high energy density and a cycle life that can compete with the best lithium-ion batteries.