Master inventor Josep DeSimone and a team of researchers at UNC Chapel Hill have been awarded a patent for a new compound that could lead to more eco-friendly battery technology.
Bryce Lapping, reporting for North Carolina Business News Wire, says the six researchers, which includes one from the University of California, were awarded the patent on Tuesday.
The six originally filed for the patent in late March 2014, at which time three of the inventors were associated with UNC-Chapel Hill.
The inventors sought to create a compound to address the need for sustainable methods to meet the increasingly large demand for energy, according to the patent application.
“A first object of the present invention is, accordingly, a liquid or solid electrolyte composition (e.g., for a capacitor or for a battery such as an alkali metal ion battery), comprising: (a) a homogeneous solvent system, said solvent system comprising a fluoropolymer, said fluoropolymer having one or two terminal carbonate groups covalently coupled thereto; and (b) an alkali metal salt dissolved in said solvent system,” the patent reads.
Lithium batteries have addressed this demand, but their use in large-scale applications – such as transportation, the application notes – remains a point of contention due to poor longevity, cost and combustibility.
The now-patented compound could potentially allow large-scale lithium batteries to work in a variety of temperatures with a low rate of combustibility, all in an eco-friendly manner.
DeSimone, who leads the DeSimone Research Group sponsored by UNC-CH and North Carolina State University, is listed as the lead inventor on the patent.
DeSimone, who has already received more than 150 patents, is one of few to have been elected to the National Academy of Medicine, the National Academy of Sciences and the National Academy of Engineering, according to his group’s website.
Recently, he championed advancements in 3-D printing. DeSimone co-founded Carbon in 2013 and is CEO of the Silicon Valley-based company.
Ashish Pandya, who now works as a postdoctoral associate at The Sheiko Group, another research group at UNC-CH, and Dominica Wong, who now works a senior chemist at Eastman Chemical Co. worked for DeSimone’s team at the time of the original filing and are also listed as inventors.
A description of the patent follows:
- FIELD OF THE INVENTION
The present invention concerns liquid and solid polymer electrolyte compositions for use in batteries such as lithium-ion batteries, lithium-air batteries, and sodium-air batteries.
- BACKGROUND OF THE INVENTION
One of the biggest challenges faced by modern society is to secure sustainable resources that meet burgeoning energy demands (R. Marom et al., Journal of Materials Chemistry 21, 9938 (2011)). One area of great interest is developing lithium (Li) batteries suitable for large-scale applications, such as transportation and energy storage (J. Tarascon and M. Armand, Nature 414, 359 (November, 2001)). Currently, Li-ion batteries are used in electric vehicles (EVs), but factors including cost and longevity limit their prevalence (O. Egbue and S. Long, Energy Policy 48, 717 (2012)). Safety is also a primary concern; most commercial Li-ion batteries consist of a flammable mixture of volatile alkyl carbonates (e.g., ethylene carbonate, dimethyl carbonate, propylene carbonate, diethyl carbonate, etc.) that serves as the electrolyte solvent. See, e.g., S. Harris et al., A combustion chemistry analysis of carbonate solvents used in Li-ion batteries, Journal of Power Sources 193, 855-858 (2009).
In the last decade, there has been extensive efforts to introduce alternative solvents, salts, and additives that can improve the quality and performance of electrolytes (D. Aurbach et al., Electrochimica Acta 50, 247 (2004)). The preparation of polyelectrolytes is an emerging area of interest due to their potential lower costs, easy handling, and better safety. Poly(ethylene oxide) (PEO) is the most prominently featured homopolymer in this field due its unique ability to solvate Li-based salts. The crystallinity of PEO, however, hinders ionic conductivity, rendering PEO-LiX electrolytes useful at temperatures between 60.degree. to 80.degree. C. (F. Croce et al., Nature 394, 456 (1998)). Dendrite formation at the anode electrode remains a persistent issue, causing shortcircuits and overcharging, which can lead to cell ignition or explosion (S. Tobishima et al., Journal of Power Sources 90, 188 (2000); H. Ghassemi et al., Applied Physics Letters 99, 123113 (2011)). Accordingly, there is a need for new electrolyte compositions for lithium ion batteries, and other types of alkali metal ion batteries.
- SUMMARY OF THE INVENTION
Liquid and solid polymer electrolyte compositions useful in alkali metal ion batteries, are described herein, along with alkali metal ion batteries (including lithium and sodium ion and air batteries) containing the same. In some embodiments, the compositions are advantageously characterized by, one, some or all of: low flammability/high flame resistance; low glass transition temperature, flexibility, high ionic conductivity, and/or a broad electrochemical stability window.
A first object of the present invention is, accordingly, a liquid or solid electrolyte composition (e.g., for a capacitor or for a battery such as an alkali metal ion battery), comprising: (a) a homogeneous solvent system, said solvent system comprising a fluoropolymer, said fluoropolymer having one or two terminal carbonate groups covalently coupled thereto; and (b) an alkali metal salt dissolved in said solvent system.
In some embodiments the alkali metal salt is a lithium salt; in other embodiments the alkali metal salt is a sodium or potassium salt.
Other ingredients, such as standard contaminants found in battery-grade reagents, initiators, and/or electrode stabilizing agents, may optionally be included.
Read the full patent at: