Technology Outline (Process Description)

The mileage per charge of an electric vehicle depends on the practical energy density of its lithium-ion battery’s cathode materials. The energy density relies on the nominal voltage and practical capacity of the cathode material. Increasing the cutoff charging voltage raises the practical specific capacity and nominal voltage, but reduces the battery’s cyclic life due to cathode-electrolyte interactions and oxygen release, posing safety concerns.

Spinel and layered lithium transition metal oxide derivatives are promising high voltage cathode material candidates. Preferred LiMO2 cathode morphologies are ~10-micrometer nano/micro-hierarchical aggregates with lower surface area and high tap density. Higher Li, Mn, and Ni content can enhance specific capacity and nominal voltage, but compromise cyclic stability and safety due to oxygen release and unwanted reactions.

To address these challenges, we implemented strategies like composition grading, carbon coating, and creating oxygen vacancies on the surface. This enabled us to achieve a specific capacity of 230mAh/g and a cutoff voltage of 4.8V vs Li.