Researchers at the Moscow Institute of Physics and Technology have discovered that replacing the solid copper substrate with perforated metal foils helps extend the lifespan of high-capacity lithium-ion batteries with silicon anodes.
Lithium-ion batteries with silicon anodes can store nearly ten times more energy than traditional graphite batteries, but their lifespan is very short due to the large expansion of silicon by 3 to 4 times during charging, which leads to it cracking and separating from the substrate.
But scientists at the Institute of Electric Propulsion at the Moscow Institute of Physics and Technology have found an innovative solution to this problem. Instead of using complex and expensive three-dimensional structures, the researchers relied on conventional copper foil perforated with lasers, with openings measuring 250 and 500 micrometers in diameter.
Researcher Alyssa Karakolina explained : "We don't yet know exactly how perforated wafers affect the stability of silicon-containing anode performance. But it is likely to be affected by the mechanical properties of the interlocking structure, the saturation of the porous film with the electrolyte, the distribution of the bonding components, and the strength of their bond to the substrate. Also, the active material, which penetrates the holes in the wafer, may act as stitches that bind the two sides of the electrode tightly, preventing it from peeling off."
The team believes the active material penetrates the perforations, bonding the two sides of the electrode and preventing its degradation. The results showed remarkable superiority: after 100 charge-discharge cycles, the anode mounted on the perforated wafer retained 90% of its capacity, compared to 60% on the solid substrate. No degradation was observed even when the discharge current was quadrupled, and the small size of the perforations further enhanced the stabilization effectiveness.
The researchers plan to test this technology on anodes containing a higher percentage of silicon, and produce a pilot batch of batteries at the institute's experimental facility.
