The work, appearing in the March issue of the journal Nano Letters, will help researchers design cheaper and more powerful rechargeable batteries with metals more common and safer than lithium.
"This work is the first visual evidence of what leads to the formation of lithium dendrites, nanoparticles and fibers commonly found in rechargeable lithium batteries that build up over time and lead to battery failure," said lead scientist Nigel Browning, a physicist at the Department of Energy's Pacific Northwest National Laboratory.
As anyone with a dying cell phone knows, it would be nice if rechargeable batteries held more power, lasted longer and were cheaper. Solving these problems could also make electric vehicles and renewable energy more attractive. Using metals such as magnesium or aluminum in place of lithium could improve batteries life and cost, but research and development into non-lithium rechargeables lags far behind the common commercial lithium ion ones.
To speed up development of rechargeable batteries, DOE funded the Joint Center for Energy Storage Research, a collaboration of several national labs, universities and private sector companies. Multidisciplinary teams of scientists explore a variety of problems, hoping to overcome them by understanding the underlying chemical principles.
For instance, rechargeable batteries suffer from the growth of dendrites, microscopic, pin-like fibers that afflict battery electrodes. Recently, JCESR researchers led by PNNL discovered a way to eliminate dendrites in lithium batteries by using a special electrolyte. To better understand how dendrites form and can be prevented at the microscopic level, another JCESR team led by PNNL's Nigel Browning devised a microscope that could examine a full working battery in action.
Unlike other views of the inner workings of batteries at high magnification, most of which use only part of a battery or have to study them under pressures not typically used in batteries, the Browning team created a complete functioning battery cell under normal operating conditions.
"This is very exciting work," said first