Cyclic Ester Electrolyte for Safer High-Nickel Lithium Batteries

A coating layer comprising at least one of an oxide, hydroxide, carbonate, or carboxylate of a divalent or trivalent metal element is applied on the surface of the NCM-based anode active material particles. This coating layer acts as an intermediary barrier that suppresses direct contact and harmful reactions between the high-nickel NCM material and the electrolyte, thereby preventing structural degradation and gas generation at high temperatures while preserving the high energy density benefits

The patent combines NCM-based anode active material with specific metal elements (divalent or trivalent metals such as Mn, Ni, Co, Cu, Zn, Al, Cr, Mo, B, Ti, V, Zr, Nb, Hf, Ta, or their combinations) to form a composite coated structure. This composite material approach allows the core NCM material to maintain its high capacity characteristics while the surface coating provides thermal stability and structural protection, resolving the contradiction between energy density and safety

The coating layer of oxide, hydroxide, carbonate, or carboxylate serves as a protective intermediary that stabilizes the surface structure of the NCM particles at high temperatures. This layer prevents structural collapse and maintains the integrity of the high-capacity NCM material during thermal stress, thereby preserving both capacity and structural stability

The patent modifies the surface composition parameters of the NCM particles by applying a coating layer with specific metal elements and chemical compositions. This parameter change at the surface level (without altering the bulk high-capacity NCM structure) enhances thermal stability and prevents structural degradation, allowing the material to maintain both high capacity and structural integrity at elevated temperatures