Sodium batteries offer an alternative to tricky lithium

livemint.com:

restricted chip-industry exports to China. Fortunately, lithium is not the only game in town. As we report this week, a clutch of firms are making batteries based on sodium, lithium’s elemental cousin.

Since sodium’s chemical properties are very similar to those of lithium, it too makes for good batteries. And sodium, which is found in the salt in seawater, is thousands of times more abundant on Earth than lithium and cheaper to get at. Most of the companies using sodium to make batteries today are also Chinese.

But pursuing the technology in the West might be a surer route to energy security than relying heavily on lithium. Besides its abundance, sodium has other advantages. The best lithium batteries use cobalt and nickel in their electrodes.

Nickel, like lithium, is in short supply. Mining it on land is environmentally destructive. Proposals to grab it from the seabed instead have caused rows.

A good deal of the world’s cobalt, meanwhile, is extracted from small mines in the Democratic Republic of Congo, where child labour is common and working conditions are dire. Sodium batteries, by contrast, can use electrodes built from iron and manganese, which are plentiful and uncontroversial. Since the chemical components are cheap, a scaled-up industry should be able to produce batteries that cost less than their lithium counterparts.

Sodium is not a perfect replacement for lithium. It is heavier, meaning sodium batteries will weigh more than lithium ones of an equivalent capacity. That is likely to rule them out in some cases where lightness is paramount.