Researchers in the US say they have developed a new technique using heat to “enable lithium-metal self-healing” to eliminate the dendrite build-up in battery anodes.
The team at New York’s Rensselaer Polytechnic Institute claim to have discovered a way to use internal battery heat “to diffuse the dendrites into a smooth layer”.
In a paper for the journal ScienceNikhil Koratkar, the John A Clark and Edward T Crossan professor of engineering at Rensselaer, said: “We have found that lithium metal dendrites can be healed in situ by the self-heating of the dendritic particles.”
The Rensselaer researchers’ proposed solution takes advantage of the battery’s internal resistive heating to eliminate the dendrite build-up. Resistive heating (also known as Joule heating) is a process in which a metallic material resists current flow and, as a result, produces heat. This “self-heating” occurs through the charging and discharging process.
Rensselaer said its 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,” Rensselaer said.
Rensselaer said the researchers first demonstrated the “this smoothening (healing) of the dendrites in a lithium-lithium symmetrical cell”. They then showed the process with the same results “in a proof-of-concept demonstration using a lithium-sulfur battery”.
“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 an electronic device is not in use,” Rensselaer said.
Koratkar added: “A limited amount of cycles at high current density would occur to heal the dendrites, and then normal operations can be resumed. Self-healing would occur as a maintenance strategy, long before the dendrites become a safety hazard.”
The research is available in detail on Rensselaer’s website.