Initially, the scientists obtained a few precursors, i.e., intermediate substances that were required for the study. The first substance was a hydroxide precursor, in which nickel, manganese and cobalt cations were mixed at the atomic level. The scientists mixed this substance with an aqueous solution of urea and a cobalt source and placed it in a hydrothermal microwave, where the mixture underwent processing for 15 minutes. The result was a precursor uniformly coated with a cobalt-enriched shell. At the final stage, the precursor was mixed with a lithium source and subjected to heat treatment at high temperatures. This made it possible to significantly speed up the production process compared to the co-precipitation method that involves salt solutions being poured into the precipitant and takes more than 12 hours.
“We use hydrothermal microwave treatment to coat the surface of the spherical particles of the cathode material precursor with a thin layer of cobalt hydroxide. Later, during its high-temperature lithiation, a concentration gradient is formed in the near-surface layer and a unique morphology emerges: the primary particles are located radially in the agglomerate and not randomly, as in the case of other materials available on the market,” Alexander Savin, senior researcher at the Center for Energy Science and Technology, is quoted as saying by Skoltech.
According to the authors’ calculations, the new material could prolong the life of a lithium-ion battery by about 10%. Another advantage is the ability to increase the energy capacity of the battery. Today, Skoltech produces prototypes of lithium-ion cells with a specific energy capacity of 250 watt-hours per kilogram (Wh/kg), which could be increased to 300 Wh/kg with the use of the new cathode material. Ultimately, this is going to improve the efficiency of energy storage devices.
