Sodium-Sulfur battery is a high energy density rechargeable battery with high efficiency of charge/discharge (89–92%) and long cycle life of battery. Sodium-sulfur battery is a molten-metal type cheaper rechargeable battery to manufacture with inexpensive materials. Sodium-Sulfur (NaS) batteries are suitable for smart grid energy storage, electric vehicles, aerospace (satellites), industrial power battery backup, uninterrupted power supply for large industries, etc.

Sodium-Sulfur battery has a solid electrolyte membrane between the anode and cathode, compared with liquid metal batteries where the anode, the cathode, and also the membrane are liquids. Sodium-Sulfur (NaS) battery cell is usually made in a tall cylindrical configuration; and the entire cell is enclosed by a steel casing that is protected from corrosion by chromium and molybdenum. This outside container serves as the positive electrode, while the liquid sodium serves as the negative electrode.

Sodium-Sulfur (NaS) Battery Safety

Pure sodium presents a hazard because it spontaneously burns/explodes in contact with water, thus the system must be protected from moisture. In modern NaS batteries, sealing techniques prevent the battery fire/explosion.

Sodium-Sulfur (NaS) Battery Limitations

Because of the operating temperatures of 300 to 350 °C and the highly corrosive nature of the sodium polysulfides, such cells are primarily suitable for large-scale non-mobile applications such as battery electric vehicles, and grid energy storage. Corrosion of the insulators was found to be a problem in the harsh chemical environment as they gradually became conductive and the self-discharge rate increased. Dendritic-sodium growth can also be a problem.

Sodium-Sulfur (NaS) Battery Advantages

  • High energy density battery
  • High specific energy battery
  • High efficiency in charge/discharge of battery
  • Long cycle life of battery with low self-dicharge rate
  • Cheapest to manufacture with inexpensive materials

Sodium-Sulfur (NaS) Battery Applications

Because of high energy density, high efficiency of charge/discharge (89–92%), and long cycle life, of Sodium-Sulfur battery is suitable for smart grid energy storage, electric vehicles, aerospace (satellites), industrial power battery backup, uninterrupted power supply for large industries, etc.