The key to eliminating dendrite buildup in lithium-ion battery anodes - exploiting the self-heating effect inside the battery
Rechargeable lithium-ion batteries are the main battery used in consumer electronics, and are increasingly becoming the battery of choice for electric vehicles and grid energy storage applications. The positive electrode (cathode) is lithium metal oxide, and the negative electrode (anode) is graphite. But scientists have not given up on lithium metal batteries with higher energy density, and are tirelessly trying to find a way out for more powerful lithium metal batteries.
Researchers at the Rensselaer Polytechnic Institute have now found a way to use the thermal energy inside the battery to diffuse dendrites into a smooth layer, or as study leader Nikhil Koratkar, a professor in the Department of Materials Science and Engineering, says, dendrites can "Repair in place" through the self-heating effect of the battery, the paper was published in the journal "Science".
The battery is basically composed of a cathode, an anode, an electrolyte, and a separator. The separator is located between the two electrodes to prevent the battery from short-circuiting due to contact with each other. In addition, the pores of the separator filled with electrolyte are ions (charged atoms) shuttle between the electrodes. channel, the more electrolyte absorbed by the separator, the higher the ionic conductivity.
When the battery is discharged, the positively charged lithium ions on the anode are transferred to the cathode to generate electricity; when the battery is charged, the lithium ions flow from the cathode back to the anode, and the battery with lithium metal as the anode is prone to the lithium metal as the anode during the repeated charge and discharge process. Unevenly deposited to form dendrites, these tricky buildups can eventually penetrate the separator and reach the cathode, shorting out the cell and posing an explosion fire risk.
Using graphite as the anode, which avoids the lithium dendrite problem, is the best battery option right now, but soon, they may no longer be able to keep up with storage capacity needs.
To make lithium metal batteries thrive, the researchers' proposed solution is to use the battery's internal resistive heating to eliminate dendrite buildup. Resistive heating (also known as Joule heating) is a process in which a metallic material resists an electric current and thus generates heat. This "self-heating" effect can occur through the process of charging and discharging.
Therefore, the researchers enhanced the self-heating effect by increasing the current density (charge-discharge rate) of the battery, and found that this process can allow the dendrites to diffuse evenly and smoothly to achieve a "healing" effect. The same results were also obtained in the lithium-sulfur battery experiment. Therefore, when the battery is not in use, the "self-healing" effect of the battery can be achieved by charging and discharging at a high rate for several cycles.
The research sounds promising. Supercharged charging can rejuvenate the battery, prevent short circuits caused by dendrites, and ensure that the battery is safer and has a high energy density, but does this prevent the battery from rapidly decaying? Maybe further research is required by the team .
