What is a Sodium Battery?
A sodium battery — more precisely called a sodium-ion battery — is a rechargeable battery that stores and releases energy using sodium ions. If you’ve heard of lithium-ion batteries (the kind in your phone or electric car), sodium-ion batteries work in almost exactly the same way.
The big difference? Instead of using lithium, they use sodium — the same element that makes up table salt.
Sodium makes up about 2.3% of the earth’s crust and is found in seawater, salt flats, and minerals worldwide. Lithium, by contrast, is much rarer and found mainly in a handful of countries. That abundance is one of sodium’s biggest selling points, and part of the potential for this battery chemistry to provide reliable and accessible power for various applications.
Sodium-ion batteries are not quite as widely available or commercially successful as other energy storage technologies, but they are growing and maturing rapidly. These batteries are particularly useful for stationary energy storage such as grid storage for renewable energy, backup power systems, and cost-sensitive electric mobility like short-range electric vehicles, e-bikes, and scooters where lower cost and good cycle life matter more than maximum energy density.
How Do Sodium Batteries Work?
Generally, batteries are made of three key parts: a positive electrode (cathode), a negative electrode (anode), and an electrolyte in between that allows ions travel back and forth.
When you charge a sodium battery, sodium ions move from the cathode through the electrolyte and get stored in the anode. When you use the battery, or discharge it, those ions flow back to the cathode.
The anode in most sodium batteries is made of hard carbon — a specialized, sponge-like form of carbon that’s very good at soaking up sodium ions and holding them in place between charges.