Researchers at Rensselaer Polytechnic Institute (RPI) have demonstrated a “self-healing” lithium-metal anode that can eliminate dendrite buildup.
Researchers are looking for ways to replace graphite anodes with lithium metal in order to boost energy density. However (as regular Charged readers know), lithium metal anodes are plagued by the buildup of dendrites, branchlike protrusions that can grow long enough to create a short circuit.
Now a team of researchers at RPI has discovered a way to use internal battery heat to diffuse the dendrites into a smooth layer. The team reported its findings in “Self-heating-induced healing of lithium dendrites,” published in Science.
“We have found that lithium metal dendrites can be healed in situ by the self-heating of the dendritic particles,” said co-author Nikhil Koratkar.
The Rensselaer team’s solution takes advantage of a battery’s internal resistive heating, which occurs during the charging and discharging process, to eliminate dendrite buildup. The researchers ramped up the self-heating effect by increasing the current density (charge/discharge rate) of the battery. The process triggered extensive surface diffusion of lithium, spreading the dendrites into an even layer.
In an actual device, dendrite healing would be carried out by battery management system software, which would provide doses of “self-healing” treatment by running a few cycles at a high rate of charge and discharge when the device is not in use.
“A limited amount of cycles at high current density would occur to heal the dendrites, and then normal operations can be resumed,” Koratkar explains. “Self-healing would occur as a maintenance strategy, long before the dendrites become a safety hazard.”