Researchers turn tape into a film to replace lithium metal battery anodes to improve lithium metal battery performance

According to foreign media reports, James Tour, a chemist at Rice University in the United States, and his colleagues turned tape into a silicon oxide film to replace the anode in lithium metal batteries.

(Image source: Rice University)

In the study, the researchers used an infrared laser cutter to turn the silicon-based adhesive on a commercial tape into a porous silicon oxide coating, mixed with a small amount of laser-induced graphene in the tape's polyimide substrate. This protective silicon oxide layer formed directly on the current collector of an existing battery.

Tour said that the idea of ​​using the tape came from previous attempts to produce free-standing films of laser-induced graphene. Unlike pure polyimide films, the tape not only produced laser-induced graphene from the polyimide substrate, but also produced a semi-transparent film where the adhesive was located, which sparked the researchers' curiosity and led to further experiments.

The researchers attached the tape to a copper current collector and rubbed it multiple times to rapidly raise the temperature to 2,300 degrees Kelvin (3,680 degrees Fahrenheit), creating a porous coating composed mostly of silicon and oxygen, bound together with small amounts of carbon in the form of graphene.

In experiments, the foam-like film absorbed and released lithium metal without forming dendrites, which can cause batteries to short-circuit and catch fire. The researchers noticed that lithium metal tends to degrade rapidly when batteries are charged and discharged using bare current collectors, but this problem was not observed in anodes coated with laser-induced silicon oxide (LI-SiO).

"In conventional lithium-ion batteries, lithium ions are inserted into the graphene structure when charging and disconnected when the battery is discharged," said the researchers. "When all graphene is used, six carbon atoms are required to store one lithium atom. But in lithium metal anodes, no graphene is used. When the battery is discharged, lithium atoms shuttle directly from the surface of the metal anode. Lithium metal anodes are considered a key technology for future battery development if safety and performance issues can be addressed."

The capacity of the lithium metal anode is 10 times higher than that of traditional graphene lithium-ion batteries, but lithium metal batteries lacking graphene usually use too much lithium metal to compensate for the loss caused by oxidation on the anode surface. "When there is no excess lithium metal on the anode, it usually degrades quickly, resulting in a battery with very limited cycle life," said the researchers. "However, on the bright side, such anode-free batteries will be lighter and perform better, but their lifespan will be short."

The researchers noted that the life of the laser-induced silicon oxide battery was doubled compared to batteries without excess lithium metal. The battery coated with laser-induced silicon oxide can be charged and discharged up to 60 times while maintaining 70% of its capacity. Tour said this could make lithium metal batteries suitable for high-performance batteries for outdoor adventures, or as high-capacity storage batteries during short-term power outages in rural areas.

It can be mass-produced using only standard industrial lasers, is fast, does not require solvents, and can be performed at or below room temperature. In addition, the technique can also produce thin films that support metal nanoparticles, protective coatings, and filters.