Scientists from the University of Michigan in the United States have developed coating for batteries electric cars, allowing them to charge 500% faster at low temperatures.
The results of a new study show that coating batteries with a thin layer of lithium borate-carbonate can increase the charging rate by 500% at temperatures as low as -10°C. Low temperatures limit charging speeds and reduce overall energy efficiency due to the chemical processes that occur during charging.
«The researchers were able to simultaneously achieve extremely fast charging at low temperatures without sacrificing the energy density of the lithium-ion battery», — explains one of the study’s authors, Associate Professor of Mechanical Engineering and Materials Science at the University of Michigan Neil Dasgupta.
The principle of operation of Li-ion batteries is the movement of lithium ions between two electrodes (anode and cathode) in the electrolyte between them. However, at low temperatures, the liquid electrolyte thicken.The battery is made of a polymeric material, which makes it difficult for electric charges to move, which increases the charging time.
This problem has been solved by increasing the thickness of the electrodes, or structural changes in the batteries themselves. However, this has further complicated the problem. In a previous study published in 2020, engineers at the University of Michigan developed what they called «new» channels in anodes that accept lithium ions during charging and send charged electrons to the cathode.
To create these channels, the scientists used lasers to create holes in the graphite layers of the anode. This allowed the lithium ions to move faster. However, at low temperatures, this approach led to the accumulation of lithium ions on the anode. This made it difficult for the electrode to interact with the electrolyte.
To prevent the formation of this layer, in the new study, the researchers coated the battery with a 20-nanometer-thick material made of lithium borate carbonate. Previous studies have confirmed that this material can accelerate the movement of lithium ions
Coverage in combination with channel technology provided 500% coverage increase in charging efficiency at low temperatures. The batteries modified with these technologies also retain 97% of their capacity even when charged up to 100 times rapidly at sub-zero temperatures.
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The results of the study were published in the journal Joule
Source: LiveScience
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