APPLICATIONS OF TECHNOLOGY:
- Energy storage for transportation applications
- Superior cycling stability and higher coulombic efficiency
- Stability towards polysulfide and minimization of polysulfide dissolution
The Li-ion rechargeable battery is costly with a low-energy density, creating a spur of research in lithium-sulfur rechargeable batteries. The lithium sulfur reaction is more than five times the theoretical energy of transition metal oxide cathode materials and graphite coupling. However, the major obstacle is the loss of sulfur cathode material as a result of polysulfide dissolution into common electrolytes, causing a shuttle effect, poor sulfur utilization, and significant capacity fade.
A strong demand for low-cost and high-energy-density rechargeable batteries has spurred lithium-sulfur (Li-S) rechargeable battery research. To address the need for ideal electrolytes for the sulfur electrode, researchers at the Berkeley Lab led by Gao Liu have developed an approach to create electrolytes that are used for rechargeable Li-S batteries (2019-169). These electrolytes have the ability to promote lithium salts dissolution into the electrolyte as well as to prevent polysulfide dissolution during cell operation.
The novel electrolyte is comprised of a highly fluorinated solvent and lithium salts as well as a bi-functional additive that forms micelle structures within the electrolyte. The micelle core selectively dissolves lithium salts, and the bulk of electrolyte solvent of highly fluorinated solvent hinders polysulfide dissolution.
In addition, an improved approach (2022-018) incorporating mixed solvents has been developed to provide high ion conductivity, stability towards polysulfide, and to minimize polysulfide dissolution in lithium-sulfur batteries. Using a co-additive to the amphiphilic electrolyte allowed the researchers to further adjust the polysulfide dissolution and precipitation properties in the electrolyte to achieve both high sulfur utilization and electrode stability. Superior cycling stability and higher coulombic efficiency were observed for Li-S cells fabricated with the micelle electrolyte compared to those using the benchmark electrolyte.
DEVELOPMENT STAGE: Proven principle
LBL PRINCIPAL INVESTIGATORS:
- Gao Liu
STATUS: Patent pending
OPPORTUNITIES: Available for licensing or collaborative research