The U.S. Army Research Laboratory in Maryland has developed new ways to make lithium-ion batteries more powerful but still safe.
The Army’s latest patent application for a new and improved battery electrolyte was published by the U.S. Patent and Trademark Office on Thursday, putting intellectual property rights on new solvents that enable higher energy densities and setting the stage for the technology to be adopted by battery manufacturers.
Through lab experimentation, Army electrochemists Drs. Arthur von Wald Cresce, Selena Russell, and Kang Xu, have created “cocktails” of new solvents, and new battery cells, that allow lithium-ion and other rechargeable batteries to safely hold more energy, according to the patent application.
"We want to push the voltage of lithium-ion batteries higher." -Dr. Arthur von Wald Cresce
First developed in the 1970s, lithium-ion batteries are small but can discharge lots of power quickly, and are preferred for consumer electronics like cell phones and the military’s field radios. They unleash their stored power when lithium ions move from the negative graphite anode to the positive lithium cathode through the electrolyte, which is flammable and can release toxic gases, so safer electrolytes are a research priority.
The names of the chemicals used in the new electrolyte are a mouthful.
For example, try saying Dimethylvinylsilyl Hexafluoro-Isopropyl Ether or Trimethylsilyl Propargylformate.
The graphite anode is important because it does not grow tiny, destructive hairs called dendrites when recharged. But graphite has capacity limitations, and the Army researchers are trying silicon anodes with very high capacities for lithium.
The Army is also exploring potential replacements for lithium-ion, such as magnesium and zinc-based batteries, which can carry twice the charge.
“The conventional electrolyte and additive typically cannot form effective stabilization and protection on surfaces of these new battery chemistries,” according to the Army’s patent application. “Therefore new electrolyte compounds have to be developed.”
TechLink, the Department of Defense’s national partnership intermediary for technology transfer, can help manufacturers access the technology so it can become available in civilian and military markets.
Through technology transfer, DoD inventions are made available to businesses and entrepreneurs for use in new products and services. And the Army Research Laboratory has over 600 inventions available.
The first step is to negotiate a license agreement, which TechLink will help companies do at no charge.
A license confers the right to practice the invention for commercial purposes and often includes related data and technical knowledge, as well as intellectual property rights in the marketplace. License fees paid to the laboratory are typically negotiable.
“The Army is developing hybrid vehicles for use on the battlefield, and that means they will also use lithium-ion batteries. Certain high-energy applications such as reactive armor and directed-energy weapons also seem suited for lithium-ion batteries, although those technologies are still developing,” Cresce said.
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