Researchers at Argonne National Laboratory have made a breakthrough in overcoming a key challenge with sodium-ion batteries, paving the way for more sustainable and cost-effective energy storage solutions for electric vehicles and the electric grid.
Tackling the Lithium Shortage
Lithium-ion batteries are currently the preferred option for EVs and renewable energy storage applications. Nonetheless, the growing demand in these types of market causes concerns about possible lithium supply shortages over the next 5 to 10 years.
Here, sodium-ion batteries make for a promising alternative. Sodium, which is more abundant and cheaper than lithium, could make sodium-ion batteries a more sustainable solution for the future. A team of researchers at Argonne National Laboratory, working with collaborators from the University of Toledo and Fudan University in China, has made a significant breakthrough on a new type of oxygen evolution reaction that could pave the way for low-cost sodium-ion electrochemical energy storage devices.
When it Comes to Cathodes, They Finally Cracked
A major obstacle to the development of sodium-ion batteries so far has been the rapid degradation in performance of the cathode containing sodium during charge and discharge cycles. Researchers at the Argonne definitely have stumbled upon a potential solution, by developing a new sodium-ion oxide cathode.
What makes this work is the particular composition of the cathode particles, which include molecules made from various transition metals, like nickel or cobalt together with iron or manganese. Nickel in the structure provides overall good capacity, while manganese to provide structural integrity.
Unfortunately, this metal “gradient” in distribution created tremendous stress inside the particles and resulted in cracks formation, rendering the cathode useless to perform. The team realized the need to solve this problem when they found that after tens of discharge-charge cycles, there was no capacity loss or structural change detected in every part except for cathode which showed substantial cracks.
Conclusion
This work is a major advance in the quest towards sodium-ion batteries replacing lithium ion technology. They have solved the critical issue of cathode performance, which brings into play an avenue for sustainable and affordable energy storage solutions for electric mobility and large-scale grid storage. A sodium-ion battery with a similar cathode could produce energy densities that are close to those of lithium iron phosphate, which bodes well for the use of sodium-ion in the future to supply ever more energy-hungry world.
