APPLICATIONS OF TECHNOLOGY:
- Lithium ion batteries for electric vehicles and consumer products
- Large scale renewable energy storage
ADVANTAGES:
- Made of inexpensive, earth abundant, non-toxic materials
- High reversible capacity
- Stable discharge capacity
- Restricts dissolution of polysulfides in electrolytes
ABSTRACT:
Berkeley Lab scientists led by Elton J. Cairns have developed a novel nanofabrication technology to make low cost, highly efficient carbon-sulfur electrodes for lithium / sulfur rechargeable batteries.
The Berkeley Lab technology creates carbon nanofibers through electrospinning of polyacrylonitrile (PAN) or other conducting polymers. Nanopores are subsequently created as those fibers are carbonized in a tube furnace, something difficult to achieve with ball milling or thermal treatments. A solution-based chemical reaction-deposition method is employed to fill the pores with sulfur. These sulfur-containing fibers have high electronic conductivity and mechanical strength and establish close contact between sulfur and the current collector. Experiments show that this nanocomposite sulfur electrode exhibits high reversible capacity and improved cycle life, even at high discharge / charge rates.
Sulfur is a promising electrode material for rechargeable lithium-ion batteries because it has a very high theoretical specific capacity of 1675 mAh g-1. However, a number of technical hurdles have prevented use of this earth abundant, inexpensive, and non-toxic element in commercial applications. The key problems are that sulfur itself is a natural insulator, and sulfur-based electrodes dissolve in organic-solvent electrolytes during charge-discharge cycles, corroding the lithium and increasing the internal resistance of the cell. The Berkeley Lab team addressed this problem with a low cost and environmentally benign technology that encapsulates sulfur in porous carbon nanofibers, which form (+) electrodes, or cathodes, with high reversible capacity.
DEVELOPMENT STAGE: Bench scale prototype
STATUS: Patent pending. Available for licensing or collaborative research.
FOR MORE INFORMATION:
Ji, L., Rao, M., Aloni, S., Wang, L., Cairns, E.J., and Zhang, Y. “Porous carbon nanofibers-sulfur composite electrodes for lithium/sulfur cells,” Energy & Environmental Science 2011, 4, 5053-5059.
SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:
Nanostructured Sulfur Electrodes for Long Life Lithium Batteries, IB-3049
Sulfur-Graphene Oxide Nanocomposite Cathodes for Lithium / Sulfur Cells, IB-3096
REFERENCE NUMBER: IB-3114
