The new polymer electrolyte will increase the power reserve of electric vehicles by up to 50%August 8, 2020
While developing a battery capable of providing electric vehicles with a range of several hundred miles, American scientists decided to replace the traditional graphite anode with lithium metal. In doing so, they managed to protect the battery from the formation of dendrites.
The lithium metal anode is able to increase the battery capacity by 30-50% and at the same time shorten the battery life due to the formation of crystal structures – dendrites – causing a short circuit when in contact with the cathode. For many years, scientists believed that solid-state electrolytes, such as those made from ceramics, could prevent dendrite formation. But this approach turned out to be not entirely effective, since the dendrites still appeared, like tiny cracks on the windshield, which gradually became larger.
Specialists from the National Laboratory. Berkeley, together with colleagues from Carnegie Mellon University, announced the creation of a new class of solid electrolyte, from polymers and ceramics. It suppresses the formation of dendrites in the embryo, even before they begin to grow.
The key element of the new material is polymers with internal microporosity (PIM), whose cavities are filled with nano-sized ceramic particles. Since the electrolyte remains flexible and elastic, manufacturers can make rolls of lithium foil with electrolyte as a laminate between the anode and the battery separator, Science Daily writes.
To demonstrate the ability to suppress dendrites, the team created a 3D image of the interaction of lithium metal with an electrolyte using X-rays and visualized the deposition of lithium layers over 16 hours, under the influence of strong currents. The lithium layer gradually grew, but no significant signs of the presence of dendrites were found.
“Our dendrite suppression technology has exciting implications for the battery industry,” said study co-author Brett Helms of the Berkeley Lab. “It enables battery manufacturers to produce safer lithium metal batteries with high energy density and long lifespan.”
Helms is also confident that lithium metal batteries made with the new electrolyte can also be used to power eVTOL (vertical takeoff and landing) electric aircraft – they can provide the necessary power and high energy storage density.
Startup Advano also proposes replacing the graphite anode of lithium-ion batteries, but not with lithium metal, but with silicon. This can increase the battery capacity by about ten times. However, silicon swells during charging and can damage the internals of the battery. To prevent this, silicon carbide particles are applied to the anode.
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