High-Nickel Cathode Core-Shell Recovery from Recycled Batteries
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Solution Overview
Problem
Conventional methods for producing lithium-ion battery cathodes require high amounts of costly virgin metal compounds and are complex, while also facing issues with thermal runaway and reduced energy density due to the use of pure lithium nickelate.
Innovation Solution
A method involving the conversion of metal sulfates in a mixed metal sulfate solution to metal hydroxides, followed by lithiation and furnacing to produce lithium nickel manganese cobaltate, which coats lithium nickelate particles with a cobalt/manganese oxide layer, reducing the need for high cobalt and manganese content and enhancing safety and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If pure lithium nickelate is used to achieve maximum energy density, then energy density is improved, but thermal stability deteriorates and susceptibility to thermal runaway increases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the cathode particle has a high-nickel core (for energy density) and a protective shell layer (for thermal stability). The shell layer contains metals like aluminum, magnesium, or calcium that form stable compounds at high temperatures, preventing thermal runaway while preserving the high energy density of the nickel-rich core.
Solution Approach 2:
The patent uses composite materials by combining lithium nickelate with other metal oxides or hydroxides to form a composite cathode structure. This composite approach allows the material to benefit from both the high energy density of lithium nickelate and the thermal stability of the additional components, resolving the contradiction between energy density and thermal safety.
2Reliability
If cobalt and manganese are added to dilute lithium nickelate to improve safety, then thermal stability is improved, but energy density deteriorates
Solution Approach 1:
The patent applies local quality by concentrating the protective metals (cobalt, manganese, aluminum, etc.) in a shell layer surrounding the high-nickel core. This spatial distribution allows the core to maintain maximum nickel content for energy density while the shell provides thermal stability, avoiding the need to uniformly dilute the entire particle which would reduce energy density.
Solution Approach 2:
The patent segments the cathode particle into distinct regions: a high-nickel core region for energy density and a protective shell region for thermal stability. This segmentation allows each region to optimize its function without compromising the other, enabling high energy density while maintaining safety.
3Reliability
If conventional gradient precipitation process is used to concentrate cobalt and manganese at the surface, then thermal stability is improved, but manufacturing complexity increases and cost increases due to high cobalt and manganese requirements
Solution Approach 1:
The patent replaces expensive cobalt and manganese with cheaper alternative metals such as aluminum, magnesium, calcium, or their combinations. These alternative metals can form stable protective layers at lower cost and in smaller quantities, reducing both material cost and the complexity of the precipitation process while achieving the same thermal stability function.
Solution Approach 2:
The patent changes the chemical parameters of the protective layer by using different metal combinations (aluminum, magnesium, calcium, or their mixtures) instead of traditional cobalt and manganese. This parameter change allows for simpler processing conditions and reduced material costs while maintaining the protective function against thermal runaway.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method results in a high nickel-to-manganese-to-cobalt ratio cathode material with improved thermal stability and energy density, reducing the amount of cobalt and manganese needed, thus lowering costs and enhancing safety and performance.
Implementation Method 1
converting metal sulfates in a mixed metal sulfate solution to metal hydroxides with a hydroxide until a solution pH from 10 to 11 is reached to produce a slurry
Implementation Method 2
furnacing the dried material above 700 degrees Celsius for 0.5 to 4 hours in the presence of oxygen to produce a LiNixMnymCozO2 material
Implementation Method 3
furnacing the dried material above 700 degrees Celsius for 0.5 to 4 hours in the presence of oxygen to produce a LiNixMnymCozO2 material
Data Source
AI summary
A more efficient and lower cost method for producing electrochemically stable, and thus safe from thermal runaway, high electrochemical capacity coated lithium nickelate is disclosed. The coated nickelate hydroxide particles are formed from a mixed metal sulfate solution (MMS) serving as the starting material that is obtained from recycled lithium ion and/or nickel metal hydride batteries. The coating of the particles includes a relatively small amount of cobalt/manganese oxide forming the surface of the nickelate particles, while the core of the particles includes a relatively large amount of nickel in relation to the weight of the coating. Battery cathode electrodes may be manufactured by using the obtained coated lithium nickelate particles as the cathode active material (CAM) in forming the battery cathodes.