Ever wonder why some expensive lithium ion batteries go dead after a certain number of charges? Mystery solved. Scientists now know the culprit is nickel, which is added during the manufacturing process to increase the battery’s capacity.
At the atomic level, in the many batteries that use lithium-nickel-manganese oxide, the manganese and oxygen atoms form orderly rows. During normal operation, lithium ions zip up and down the empty channels in between the rows to charge or discharge the battery.
Researchers thought that the added nickel atoms were distributed evenly among the rows. However, a team led by scientists at Pacific Northwest National Laboratories has new high-resolution 3-D images that tell a different story. Rather than being evenly distributed, the nickel clumps together and blocks the channels, preventing the flow of ions and keeping the battery from charging. The research is published in the journal Nano Letters. [Meng Gu et al., Conflicting Roles of Ni in Controlling Cathode Performance in Li-ion Batteries]
The nickel blockage appears to be a result of the manufacturing process. So identifying and controlling manufacturing conditions may one day make batteries last longer. And keep your current current.
—Gretchen Cuda Kroen
