Positive Electrode Material Resistivity for Safer Li-Ion Batteries

The patent applies local quality by creating a positive electrode active material with non-uniform composition distribution, where additive elements are concentrated at specific regions (surface or interior) to provide localized safety functions while maintaining high discharge capacity in other regions. This spatial differentiation of material properties resolves the contradiction between overall capacity and localized safety requirements.

The patent employs composite materials by combining multiple elements (lithium, transition metal M, additive elements, and oxygen) in a layered rock-salt crystal structure. The composite nature allows simultaneous achievement of high discharge capacity (through the active lithium and transition metal) and enhanced safety (through the additive elements that prevent internal short circuits), resolving the contradiction between these two opposing requirements.

The patent applies parameter changes by precisely controlling the composition parameters (ratios of lithium, transition metal M, and additive elements) and crystal structure parameters (layered rock-salt structure with specific space group). These parameter optimizations enable the material to maintain both high discharge capacity and excellent cycle performance by preventing crystal structure degradation during repeated charge-discharge cycles.

The composite material structure with additive elements distributed in the layered rock-salt crystal lattice provides structural stabilization during cycling. The additive elements act as structural reinforcement that prevents degradation, allowing the material to maintain both high discharge capacity and long cycle life, resolving the contradiction between capacity and durability.

The patent resolves this contradiction by applying local quality - concentrating additive elements at specific locations (such as surface regions or grain boundaries) where they provide maximum structural stabilization benefit. This localized addition minimizes the overall amount of additive elements needed, thereby preserving more active material content for high discharge capacity while still achieving excellent cycle performance.

The patent optimizes the concentration parameters of additive elements to achieve the minimum effective amount needed for crystal structure stabilization. By precisely controlling the additive element content within optimal ranges, the patent maintains both cycle performance improvement and high discharge capacity, resolving the contradiction between these two parameters.