Fluorinated Li-Rich Cathode Composition for Cycle Durability

The patent changes the chemical composition parameters by adding fluorine (F) to the lithium-transition metal composite oxide, specifically controlling the F content at 0.01-0.10 mol ratio relative to transition metals. This parameter modification suppresses transition metal elution while preserving the lithium-excess composition (Li/transition metal > 1) that provides high capacity

The patent creates a composite material system by combining lithium-excess lithium-transition metal composite oxide with fluorine-containing compounds. The composite structure integrates the high-capacity lithium-excess oxide with fluorine that forms protective phases, achieving both high capacity and improved durability through the synergistic composite material

The patent optimizes the fluorine content parameter within a specific range (0.01-0.10 mol ratio) to achieve the best balance between durability improvement and capacity maintenance. Additionally, the patent introduces a second element M with specific properties (electronegativity 1.5-2.5, atomic radius 1.2-2.0 Å) to further enhance capacity retention while maintaining durability benefits

The patent develops a multi-element composite material system combining lithium-excess lithium-transition metal composite oxide, fluorine, and element M. This triple-component composite achieves superior performance by combining the elution-suppressing effect of fluorine with the capacity-enhancing effect of element M, resulting in both improved durability and higher capacity maintenance rate