The first electric battery was made by an Italian scientist Alessandro Volta in 1800. The V for volts has been derived from his name. The world has realised that it is time to switch over from coal and other fossil fuels to more renewable energy resources such as the sun and the wind. However, these sources are not consistently exploitable, as there are cloudy days and still nights. These renewables require a storage device that will pack the surplus energy. That storage device is a battery. It supplies power when the sun does not shine, and the wind does not blow.

Voltas cell used either sodium chloride or sodium hydroxide as an electrolyte between the plates of positive and negative electrodes. The common element of the electrolyte is sodium.

Thus sodium debuted on the battery landscape. Lithium is another element used in batteries and was discovered 17 years later. Sodium was later replaced by Lithium.

However, sodium is staging a comeback. Relience acquired Faradion, a British firm in the field of sodium-ion batteries. Natron, a California-based company and CATL, a Chinese company has improved sodium-ion technologies.

Why this renewed interest in sodium? As a matter of fact, sodium and lithium are cousins on the periodic table and behave similarly. However, lithium scores over sodium in batteries. Sodium is thus reduced to the position of a poor man’s lithium.

Lithium is expensive. It costs $80000 per tonne whereas sodium costs less than $800 per tonne. There is more sodium than lithium in the world.

Storage capacity of sodium batteries is less ounce for ounce than lithium batteries. You require a heavier sodium battery for the same capacity. Scientists, therefore, researched more on lithium battery technology. The Nobel of 2019 in chemistry went to these scientists.

Sony launched a handheld video camera with a rechargeable lithium battery in 1991. Since then, there is constant improvement in lithium-ion batteries.

Sodium ion batteries are economical. It is easy to extract sodium. There is no need of cobalt in sodium batteries. There is constant improvement in sodium batteries too, and are now far better than lead acid batteries used in cars. They have reached a stage where lithium batteries were a few years ago. Faradion’s batteries store about 160 watt-hours of energy per kilogram. It is similar to lithium batteries using lithium-iron phosphate (LFP) technology.

It is now the time when both lithium and sodium batteries will co-exist. Lithium will be the first choice for portable devices. Elsewhere, where battery weight and low energy density do not matter, sodium batteries could be used, say for short-range vehicles such as e-rickshaws, home invertors, renewable grids and city cabs.