Kevlar Barrier Could Lead to Safer Lithium-ion BatteriesColby Hochmuth | January 28, 2015
A battery technology innovation from the University of Michigan could result in a safer lithium-ion battery.
The innovation involves an advanced barrier between the electrodes. The barrier, made with nanofibers extracted from Kevlar, stifles the growth of metal tendrils that can become unwanted pathways for electrical current.
"Unlike other ultra-strong materials such as carbon nanotubes, Kevlar is an insulator," says Nicholas Kotov, the Joseph B. and Florence V. Cejka Professor of Engineering. "This property is perfect for separators that need to prevent shorting between two electrodes." Kevlar is also popularly known as a material in bulletproof clothing.
Ann Arbor, Mich.-based Elegus Technologies plans to bring this research to market, with mass production expected to begin in the fourth quarter of 2016.
The membrane was made by layering the fibers on top of each other in thin sheets. This keeps the chain-like molecules in the plastic stretched out, an important factor for good lithium-ion conductivity between the electrodes.
"The special feature of this material is that we can make it very thin, so we can get more energy into the same battery cell size, or we can shrink the cell size," says Dan VanderLey, an engineer who helped found Elegus through the university's Master of Entrepreneurship program.
The heat resistance of the Kevlar material might also mean that the membrane has a better chance of surviving a fire, which leads to safer batteries.
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