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An Innovative Technique to Provide Longer Life to Lithium Anodes

The key to producing better rechargeable lithium batteries could be a little brushing. Chemistry professor James Tour’s lab at Rice University developed a method for fine-tuning the surface of battery anodes by merely brushing particles into them.

Scanning electron microscope images show a sequence of lithium foils treated by scientists at Rice University. Brushing metal powder into lithium anodes for rechargeable batteries can prevent the formation of damaging dendrites. The scale bars represent 100 microns. Image Credit: Tour Group, Rice University.

The powder forms a thin, lithiated coating on the anode after adhering to it, successfully preventing the growth of potentially harmful dendrites.

The ability to tune lithium metal foil's surface energy without using hazardous solvents was demonstrated by a powder of phosphorus and sulfur crushed into its surface.

After 340 charge-discharge cycles, anodes with these modifications and lithium-iron-phosphate-oxide cathodes in test cells demonstrated 70% greater capacity retention than commercial batteries.

The research is published in Advanced Materials.

This would simplify the manufacture of high-capacity batteries while greatly improving them. Sanding these powdered solids into a lithium metal anode dramatically reduces dendrite formation that can short circuit a battery, as well as the accelerated consumption of the materials.

James Tour, Professor, Materials Science and Nanoengineering, Rice University

Weiyin Chen, the lead author and a Rice graduate student, worked hard in the lab with his colleagues to test various powder possibilities on their electrodes. To develop the fine film that reacts with the lithium metal and creates a solid passivation layer, they first dusted on powder to give the surface texture.

Chen and co-author Rodrigo Salvatierra, a former postdoctoral researcher who is currently an academic visitor in the Tour lab, developed test batteries and discovered the treated anodes retained ultralow polarization, another negative trait for lithium-ion batteries, for more than 4,000 hours, or about eight times longer than bare lithium anodes.

According to Tour, the powders successfully adjust the electrodes’ surface energies, resulting in a more consistent behavior throughout the material.

Tour added, “This provides a metal composite surface that prevents the loss of lithium metal from the anode, a common problem in lithium metal batteries. Lithium metal batteries far exceed the capacity of traditional lithium-ion batteries, but the lithium metal is often difficult to repeatedly recharge.

Study lead author Chen stated, “The powder at the lithium metal surface produces an artificial passivation layer that improves the stability throughout the charge-discharge cycles. Using this brush-on method, the metal surface is stabilized so that it can be safely recharged.

The researchers also pulverized powder into a sodium electrode and found the approach significantly stabilized its voltage overpotential, demonstrating the method could have broader utility.

The findings are consistent with the previous finding of Tour and mechanical engineer C. Fred Higgs III of Rice that sanding particular particles into surfaces can make them superhydrophobic or extremely resistant to water.

Rice alumni John Li and Duy Luong, graduate students Jacob Beckham, Nghi La, and Jianan Xu, as well as academic visitor Victor Li, are co-authors of the study. Tour is a professor of computer science, materials science, and nanoengineering at Rice and holds the T.T. and W.F. Chao Chair in Chemistry.

The study was funded by the Air Force Office of Scientific Research (FA9550-19-1-0296).

Journal Reference:

Chen, W., et al. (2022) Brushed Metals for Rechargeable Metal Batteries. Advanced Materials. doi:10.1002/adma.202202668.


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