Researchers at Stanford University have created a carbon-coated lithium anode, which has performed 150 charge/discharge cycles without forming dendritic spines at 99% Columbic efficiency.
The team placed layers of amorphous carbon to form a protective coat around the lithium anode, thus allowing it to expand and contract without causing dendritic growth at the electrolyte-electrode interface, claimed the Stanford team in a research paper published in Nature Nanotechnology.
To build the coat, the researchers placed a layer of polystyrene spheres 500 nanometers across. A layer of amorphous carbon was deposited on top of the spheres. The polystyrene spheres were then ablated with heat, leaving the layer of carbon sitting on top of a copper backing. Lithium was then electrodeposited onto the copper, filling in the space below the carbon cap to form the electrode.
The researchers claimed they managed to increase the efficiency of a lithium anode battery from 96% to 99%. But more research needs to be done to get the anode’s efficiency up to 99.9% over a long period of charging cycles, the team said. The test run ended after 150 cycles and the batteries were not tested at very high charging rates.
A stable performance at high charging rates is necessary if the anode is to be commercially available and integrated in an EV or consumer electronics battery.