Lithium is relatively rare and rather difficult to process for use in batteries. Sodium is abundant and easy to work with. There are chemical similarities between the two elements that suggest sodium-ion batteries could be a low cost — and environmentally friendly — alternative to lithium ion batteries.
There’s only one problem. Sodium-ion batteries do not perform as well or as long as their lithium ion cousins — yet. That may be changing, however, as research into sodium-ion batteries continues. Professor Jong Min Yuk and a team of scientists at the Korea Advanced Institute of Science and Technology report they have made significant progress toward creating high performing sodium-ion batteries by experimenting with copper sulfide electrodes. Their research was published recently in the journal Advanced Science.
Researchers presented a new strategy for extending sodium-ion batteries’ cyclability using copper sulfide as the electrode material. This strategy has led to high-performance conversion reactions and is expected to advance the commercialization of sodium-ion batteries as they emerge as an alternative to lithium ion batteries.
The research confirmed that copper sulfide is a superior electrode material that is pulverization-tolerant and induces capacity recovery. Using them should allow sodium-ion batteries to have a useful life of 5 years or more if charged once a day.
Many conventional battery materials such as graphite, which is commonly used in lithium ion batteries, usually experience severe capacity degradations due to having completely different crystal structures and large volume expansion before and after the reactions, according to a report by Science Daily. However, copper sulfides underwent a gradual crystallographic change to make the semi-coherent interfaces, which eventually prevented the pulverization of particles. Based on this unique mechanism, the team confirmed that copper sulfide exhibits a high capacity and high cycling stability regardless of its size and morphology than other electrode materials.
Professor Yuk says, “Sodium-ion batteries employing copper sulfide can advance sodium-ion batteries, which could contribute to the development of low-cost energy storage systems and address the micro-dust issue.”
There won’t be sodium-ion battery cells available for your electric vehicle any time soon, but on-going research means they could be a part of the energy storage picture in the future. Lithium ion batteries rely on lithium and cobalt, both of which are difficult to recycle because of their toxicity. Putting aside any price advantage, sodium-ion batteries would not have the same toxic concerns. In addition, cobalt is obtained primarily from the Democratic Republic of Congo, where its extraction raises serious concerns because of the likelihood that child laborers are involved.
Sodium-ion batteries today are at about the same stage of development as lithium ion batteries were a decade ago. The world will need all the battery storage it can find to transition to a zero carbon economy. If sodium-ion batteries can move that transition forward, the will be good news for the planet.