Electric vehicle batteries have made great strides in recent years, but their limited energy storage capacity has led many to abandon gasoline-powered cars. That could change, however, as scientists have developed a new anode material that is said to increase capacity by as much as four times.
The battery contains two electrodes – anode and cathode- ions – that travel between electrolytes. Among other things, the capacity of the battery is affected by the number of electrons that can accumulate in the anode.
Usually, those anodes are made of graphite. According to scientists at the Korea Institute of Science and Technology (KIST), silicon has 10 times the energy storage capacity of graphite, but silicon as an anode material has one major drawback – silicon expands during charging/discharge, causing its surface to rupture, resulting in a sharp drop in its capacity. Although attempts have been made to produce stable silicon anodes, the cost and complexity of the technologies involved often make them commercially unfeasible.
KIST’s new technology is different. Dr. Hun-Gi Jung and his colleagues first dissolved the starch derived from sweet potatoes in water, dissolved the silicon in corn-derived oil, and then mixed and heated the two solutions. The result is a carbon-silicon composite, in which tiny carbon spheres prevent silicon from melting. It is reported that when tested, it was found that the anode made of composite materials has four times the storage capacity of graphite-like anodes, but they remained stable during the 500 charge/discharge cycle. In addition, the new anode battery can be fully charged to 80% of its full capacity in as little as five minutes.
“The simple approach we use and the composites we develop with excellent performance are likely to be commercialized and mass produced,” says Jung. The composite material can be used in electric vehicles and lithium-ion batteries for energy storage systems. “
Scientists described the study in a recent paper published in the journal Nano Letters.