APPLICATIONS OF TECHNOLOGY:
- Rechargeable batteries
- Electric vehicle batteries
- Drones and electric aircraft batteries
- Moderate ion conductivity
- Stability towards polysulfides
- Promotes the polysulfide affiliation with the electrode substrate to prevent polysulfide dissolution
- Homogeneous distribution of all current electrolytes and additives for the electrolyte
The primary challenge in Lithium-Sulfur (Li-S) battery development has been the loss of sulfur cathode material as a result of polysulfide dissolution into common electrolytes. This reaction leads to poor sulfur utilization and significant capacity fade, which have been barriers in the widespread use of rechargeable Li-S batteries. This electrolyte invention overcomes these limitations by exhibiting such properties as moderate ion conductivity, stability towards polysulfides, and the promotion of the polysulfide affiliation with the electrode substrate to prevent polysulfide dissolution. Additionally, it enables the development of new electrolytes and additives for Li-S batteries with very low polysulfide dissolution. The advantages of the novel technology can propel the advent of Li-S batteries that ultimately satisfy demand in energy storage for transportation applications.
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. These electrolytes have the ability to promote lithium salt (e.g., LiTFSI) dissolution into the electrolyte as well as to prevent polysulfide dissolution during cell operation.
The crux of the invention is novel electrolyte structures and compositions. The electrolyte is comprised of a highly fluorinated solvent and a lithium salt as well as a bi-functional additive that forms micelle structures within the electrolyte. The micelle core selectively dissolves lithium salt, and the bulk of electrolyte solvent of highly fluorinated solvent hinders polysulfide dissolution. Studies demonstrated that the combination solvent can effectively dissolve LiTFSI to 0.5 M concentration in the micelle core for two different additives.
DEVELOPMENT STAGE: Proven principle
FOR MORE INFORMATION:
Yangzhi Zhao, et al. “A Micelle Electrolyte Enabled by Fluorinated Ether Additives for Polysulfide Suppression and Li Metal Stabilization in Li-S Battery.” Frontiers in Chemistry, 19 June 2020
STATUS: Patent pending. Available for licensing or collaborative research.
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