Aug. 25 (UPI) -- Scientists at Drexel University have developed a method to turn electrolyte solution into a safeguard against the chemical process that causes battery fires.
Lithium ion batteries, widely-used in mobile devices, have one of the longest lifespans of commercial batteries made today, but are also responsible for recent high-profile fires due to short-circuiting.
The study, published today in Nature Communications, used nanodiamonds, tiny diamond particles 10,000 times smaller than the diameter of a hair, to halt electrochemical deposition known as plating that can lead to short-circuiting in lithium ion batteries.
"Battery safety is a key issue for this research," Dr. Yuri Gogotsi, a professor in the College of Engineering at Drexel University, said in a press release.
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"Small primary batteries in watches use lithium anodes, but they are only discharged once. When you start charging them again and again, dendrites start growing. There may be several safe cycles, but sooner or later a short-circuit will happen. We want to eliminate or, at least, minimize that possibility."
When batteries are used and charged, the electrochemical reaction results in the movement of ions between the two electrodes of the battery. This repositioning of ions can create tendril-like buildups known as dendrites.
Dendrites are one of the main causes of lithium ion battery meltdown leading to fires. When dendrites form inside the battery over time, they can reach the point where they push through the separator, a porous polymer film that prevents the positively charged part of a battery from touching the negatively charged part.
Current battery designs include one electrode made of graphite filled with lithium instead of pure lithium to avoid dendrite formation. However, lithium intercalated graphite stores about 10 times less energy than pure lithium.
Researchers were able to increase energy storage when dendrite formation was eliminated in pure lithium electrodes.
They added nanodiamonds to the electrolyte solution in a battery to eliminate dendrite formation. Lithium ions can be attached to nanodiamonds, and mixing them into the electrolyte solution of a lithium ion battery slows dendrite formation to nearly nothing over the course of 100 charge-discharge cycles.
"It's potentially game-changing, but it is difficult to be 100 percent certain that dendrites will never grow," Gogotsi said. "We anticipate the first use of our proposed technology will be in less critical applications -- not in cell phones or car batteries. To ensure safety, additives to electrolytes, such as nanodiamonds, need to be combined with other precautions, such as using non-flammable electrolytes, safer electrode materials and stronger separators."
