Explained: Move over lithium-ion batteries, sodium-ion may be the future 

Electric vehicles are becoming increasingly popular the world over, as consumers want vehicles with little to no emissions and governments promote such vehicles to meet their own net-zero emission goals. But the cost of EVs, when compared to internal combustion engine vehicles, has been a major resistance factor for a more distributed adoption.

One of the major factors behind the higher costs of EVs are their lithium-ion (Li-ion) batteries. Some estimates suggest that lithium-ion batteries, which make up the majority of all batteries across all sorts of electronic devices, contribute to 20-40 percent of EVs’ costs.

While automobile manufacturers, battery makers, and various startups in the ecosystem are working on developing alternatives to lithium-ion batteries, few options already exist. One of the most promising alternatives is the use of sodium-ion (Na-ion) batteries over lithium-ion batteries. Na-ion batteries have several advantages over the traditional Li-ion batteries in a variety of end-uses.

Lithium and sodium are both alkali metals, and are right next to each other on the periodic table. Sodium and Lithium consequently share a lot of similarities.

Na-ion batteries are significantly cheaper than Li-ion batteries due to the fact that sodium is much more easily harvestable than lithium and is available in much higher quantities on Earth. Sodium can easily be extracted from salt, which itself is found in extremely high quantities in ocean and seawater, and can produce clean drinking water as a result as well.

Additionally, unlike Li-ion batteries that need the presence of the highly expensive cobalt, Na-ion batteries use iron and manganese, which are much cheaper in comparison. The production of Na-ion also avoids the ethical implication of using cobalt, which is mostly mined in the Democratic Republic of Congo and is linked to various cases of human rights abuses.

While Na-ion batteries can be a viable and cheaper alternative to Li-ion batteries for EVs, there are a few hurdles that have to be overcome. One is the fact that Na-ion batteries are much less energy-dense in comparison, though as compensation they are much lighter than Li-ion batteries.