Creating higher energy density lithium-ion batteries for renewable energy applications
The researchers employed surface chemical characterization as a strategy for identifying and minimizing residual hydroxide and carbonate impurities from the synthesis of NCA (nickel, cobalt, aluminum) nanoparticles. They realized the LIB cathode surfaces first needed to be prepared by suitable annealing, a process by which the cathode nanoparticles are heated to remove surface impurities, and then locked into the desirable structures with an atomically thin graphene coating.
The graphene-coated NCA nanoparticles, which were formulated into LIB cathodes, showed superlative electrochemical properties, including low impedance, high rate performance, high volumetric energy and power densities, and long cycling lifetimes. The graphene coating also acted as a barrier between the electrode surface and the electrolyte, which further improved cell lifetime.