Water-Based Metal Doping for High-Nickel Battery Cathodes

The patent changes the physical state parameter of the dopant from solid (in dry doping) to aqueous solution form, enabling the dopant to be introduced in a dissolved state during the lithiation sintering step. This parameter change allows the dopant to be incorporated more efficiently without being limited by solid-state reaction kinetics, thereby improving doping efficiency while maintaining acceptable reaction rates.

The patent changes the temperature parameter by conducting the doping process in an aqueous solution at temperatures below the melting point of the dopant salt. This allows the use of dopant salts with a wide range of melting temperatures, including those that would be unsuitable for dry doping methods. The aqueous environment enables dopant incorporation without requiring the salt to melt, thus expanding the versatility of suitable dopant salts while maintaining doping efficiency.

The patent extracts the dopant incorporation step from the co-precipitation process by introducing the dopant during the lithiation sintering step rather than during co-precipitation. This separation allows the main synthesis process to proceed without dopant contamination of the waste stream, while the dopant is incorporated into the cathode material through the lithiation process. The aqueous solution used for dopant introduction can be more easily managed and the dopant is efficiently incorporated, reducing waste.

The patent uses an aqueous solution as an intermediary medium to deliver the dopant to the cathode material during lithiation sintering. The dopant is introduced in dissolved form, allowing uniform distribution throughout the material as the lithium ions are inserted. This intermediary approach prevents dopant aggregation that would occur with direct solid-state mixing, while still achieving sufficient doping levels to stabilize the cathode structure and prevent Ni migration.