Doped Olivine Cathode Material for High-Voltage Li-Ion Batteries

The patent applies local quality by creating a core-shell structure where the core contains high-capacity lithium compounds (Li-rich layered oxide) and the shell contains conductive materials (carbon coating, metal nanoparticles). This localized differentiation allows the core to provide high energy density while the shell provides enhanced conductivity and charge-discharge rate, resolving the contradiction between energy density and charge-discharge performance.

The patent employs composite materials by combining Li-rich layered oxide with conductive additives (carbon black, graphene, metal nanoparticles) to form a composite positive electrode material. This composite structure integrates the high capacity of lithium-rich compounds with the high conductivity of carbon and metal materials, simultaneously achieving high energy density and fast charge-discharge rates.

The patent applies parameter changes by optimizing the voltage window and using voltage stabilizing additives. The positive electrode is designed to operate at high voltages (4.2-4.4V) while incorporating protective coatings and dopants that stabilize the crystal structure at these elevated voltages, preventing degradation and maintaining lifespan despite the high operating voltage conditions.

The patent implements beforehand cushioning by applying protective coatings (carbon coating, aluminum oxide, lithium phosphate) on the positive electrode particles before assembly. These protective layers act as cushioning barriers that prevent direct contact between the high-voltage electrode materials and the electrolyte, reducing side reactions and structural degradation that would otherwise occur at high operating voltages, thus preserving battery lifespan.

The patent applies partial or excessive action by incorporating conductive materials at optimized but not excessive levels. Carbon coatings are applied as thin uniform layers (1-5 nm) rather than thick coatings, and conductive additives are included at 1-5 wt% rather than higher concentrations. This provides sufficient conductivity enhancement for efficient charge-discharge while minimizing the volume and weight occupied by non-active conductive materials, thus preserving energy density.

The patent uses local quality by concentrating conductive materials at critical locations where they provide maximum benefit. Carbon coatings are applied specifically on particle surfaces where electron transfer occurs, and metal nanoparticles are dispersed at grain boundaries and contact points. This localized placement of conductive materials maximizes their effectiveness for charge-discharge efficiency while minimizing their overall content to preserve energy density.