Micrometer silicon particles prevent the formation of dendrites in a battery with a solid electrolyte. The lifetime of the prototype is several times that of the batteries of current electric cars.
Batteries with a solid electrolyte promise a fundamental improvement in the properties of electric cars, but although almost every major car company that deals with electric cars is working on their development, they all promise this new generation to be on the market in a few years. Researchers at Harvard University are now coming up with an innovation that Electrek, a website dealing with electromobility, calls a breakthrough.
One of the biggest challenges facing solid electrolyte battery developers is the formation of dendrites on the surface of the lithium anode. These are microscopic deposits of metal that “grow” like roots into the electrolyte and can breach the anode-cathode barrier, short-circuiting the battery and causing a fire hazard.
However, the formation of dendrites is already a problem due to the fact that they form an uneven surface of the anode, and with further charging cycles, the unevenness increases. In 2021, a team of researchers at the John A. Paulson School of Engineering and Applied Sciences, part of Harvard University, developed a prototype battery in which the formation of dendrites was limited and those that formed were captured.
Recently, however, this team announced that it completely prevented the formation of dendrites. For this, it uses silicon particles with a size in the order of micrometers as part of the anode. These regulate the lithiation reaction and enable uniform attachment of lithium ions to the anode. “Lithium wraps the silicon particle like a hard chocolate shell around the inside of a candy,” compared materials science professor Sin Li.
Due to the fact that the surface of the anode remains completely smooth, the movement of ions between the anode and the cathode can be much faster and the battery can be recharged within 10 minutes. What’s more, the prototype, roughly the size of a postage stamp, managed to retain 80% capacity after 6,000 charge cycles. For the batteries of current electric cars, the lifetime estimate is 1,500-2,000 charging cycles.
“Lithium anode batteries are considered the holy grail of batteries because they have ten times the capacity of conventional graphite anodes and can fundamentally improve the range of electric vehicles,” commented Li. “Our research is an important step towards more practical solid electrolyte batteries for both industrial and commercial use,” he added.
However, as important as the discovery by the Harvard researchers is certainly, how close it brought solid electrolyte batteries to being available at a reasonable price in production cars is still in question.
2024-01-19 15:54:00
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