Accumulateur sodium-soufre

A sodium–sulfur battery is a type of molten-salt battery that uses liquid sodium and liquid sulfur electrodes. This type of battery has a similar energy density to lithium-ion batteries, and is fabricated from inexpensive and non-toxic materials. However, due to the high operating temperature required (usually between 300 and 350 °C), as well as the highly corrosive and reactive nature of sodium and sodium polysulfides, these batteries are primarily suited for stationary energy storage applications, rather than for use in vehicles. Despite their low cost, molten sodium-sulfur batteries suffer from safety and durability issues, such as a short cycle life of fewer than 1000 cycles on average. As a result, these batteries have not achieved significant commercial deployment. Like many high-temperature batteries, sodium-sulfur cells become more economical with increasing size. This is because of the square-cube law: large cells have less relative heat loss, so maintaining their high operating temperatures is easier. Commercially available cells are typically large with high capacities (up to 500Ah). A similar type of battery called the ZEBRA battery, which uses a NiCl2/AlCl3 cathode in place of sulfur, has had greater commercial interest in the past, but as of 2023 there are no commercial manufacturers of ZEBRA. Room-temperature sodium-sulfur are also known. They use neither liquid sodium nor liquid sulfur and operate on entirely different principles and face different challenges than the high-temperature molten Na-S batteries discussed here. Typical batteries have a solid electrolyte membrane between the anode and cathode, compared with liquid-metal batteries where the anode, the cathode and the membrane are liquids. The cell is usually made in a cylindrical configuration. The entire cell is enclosed by a steel casing that is protected, usually by chromium and molybdenum, from corrosion on the inside. This outside container serves as the positive electrode, while the liquid sodium serves as the negative electrode.