Daily Archives: April 10, 2018

Ultra-Powerful Batteries

From smartphones to electric vehicles, many of today’s technologies run on lithium ion batteries. That means that consumers have to keep their chargers handy. An iPhone X battery only lasts for 21 hours of talk time, and Tesla’s model S has a 335-mile range—which means you could expect to make it from Newark, Delaware to Providence, Rhode Island, but not all the way to Boston, on one charge. Scientists all over the world—including  even the inventor of lithium ion batteries himself, John Goodenough—are looking for ways to make rechargeable batteries safer, lighter, and more powerful.

Now, an international team of researchers led by Bingqing Wei, a professor of mechanical engineering at the University of Delaware and the director of the Center for Fuel Cells and Batteries, is doing work that could lay the foundation for more widespread use of lithium metal batteries, which have more capacity than the lithium ion batteries commonly used in consumer electronics today. The team developed a method to mitigate dendrite formation in lithium metal batteries, which they  have described in a paper published in Nano Letters.

In a lithium ion battery, the anode, or current-generating side, is made of a material, such as graphite, with lithium ions bound to it. The lithium ions flow to the cathode, or current-collecting side.

In a lithium metal battery, the anode is made of lithium metal. Electrons flow from the anode to the cathode to generate electricity. Rechargeable batteries made of lithium metal hold a lot of promise because lithium is the most electrically positive metal and has a very high capacity.

“Theoretically, lithium metal is one of the best choices for batteries, but it is hard to handle in practice,” Wei said.

Lithium metal batteries have been inefficient, unstable, and even a fire hazard thus far. Their performance is hampered by lithium dendrites, formations that look like tiny stalagmites made of lithium deposits. As a battery is being used, lithium ions collect on the anode. Over time, the lithium deposits become non-uniform, leading to the formations of these dendrites, which can cause the battery to short circuit.

Source: http://www.udel.edu/