Solid State Lithium-Sulfur Battery
Publication Date: 2017-Jan-13
The IP.com Prior Art Database
High temperature, solid state lithium-sulfur battery
The sodium-sulfur battery is a high temperature battery that has a high theoretical energy density of approximately 760 Wh/kg. The sodium-sulfur battery has a reasonable energy efficiency of 85%, a long lifetime of greater than 15 years, and no self-discharge. The anode is sodium, the cathode is sulfur, and the separator is beta-alumina. These materials have low toxicity, are inexpensive, and readily available. However, high temperatures greater than 300 °C are required to keep the electrode materials in a liquid state in order to wet the electrolyte surface and maintain sufficiently high sodium ion conductivity through the beta alumina separator. At these temperatures, material corrosion issues are a significant problem. In addition, the high operating temperatures have limited the use of this technology to stationary applications.
A new high temperature lithium-sulfur battery concept is proposed that operates at 180 °C, which is substantially lower than the operating temperature of the sodium-sulfur battery. In addition, it can provide ~1.7 times more specific energy density than the sodium sulfur battery. The proposed lithium-sulfur battery has lithium metal as anode, sulfur as cathode, and a solid state lithium ion conducting electrolyte as separator.
In the original concept, the cell is operated at 180 °C so that both the anode and cathode are in the liquid state. The proof-of-concept cell is shown in Figure 1. The sulfur cathode was formed by melting sulfur into Ni foam, which served as the current collector for the cathode and held the sulfur while in a molten state. No liquid electrolyte is used in this concept. The cathode structure can include sulfur, ionic conducting media, and electronic conducting media. Ionic conducting media can include polymer electrolytes, inorganic solid electrolyte, or a combination of both; conducting media can include carbon, carbon nanotubes, carbon nanofibers, or metallic particles. The solid state electrolyte was a zirconium-containing li...