Cathode Active Material Recycling by Direct Annealing Without Pre-Washing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for recycling positive electrode active materials from lithium secondary batteries face environmental pollution, high costs, and risks of explosion due to the use of acids and organic solvents, while also failing to maintain battery performance and efficiency.
Innovation Solution
A recycling method that involves direct annealing of single-particle positive electrode active materials with a lithium precursor, followed by milling and surface-coating, without pre-washing, to adjust crystal structure and crystallite size within specific ranges, ensuring fluorine content and improving charging capacity and resistance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acid and organic solvent are used in the recycling process, then metal elements can be recovered, but environmental pollution and explosion risks occur
Solution Approach 1:
The patent changes the chemical parameters of the recycling process by replacing acidic and organic solvent-based methods with an alkaline aqueous solution system. Specifically, it uses sodium hydroxide or potassium hydroxide solutions to dissolve the aluminum current collector, enabling metal recovery without the harmful effects of acids and organic solvents, thus resolving the contradiction between safety and environmental harm.
Solution Approach 2:
The patent creates a safer, more environmentally friendly processing environment by using aqueous alkaline solutions instead of flammable organic solvents and corrosive acids. This substitution eliminates explosion risks and reduces environmental pollution while maintaining effective metal recovery capabilities.
2Manufacturing precision
If pre-washing process is included in recycling, then material purity is improved, but productivity and economic efficiency decrease
Solution Approach 1:
The patent performs preliminary separation by using alkaline solution to selectively dissolve the aluminum current collector before recovering the active material. This preliminary action removes the need for subsequent pre-washing steps, as the active material is already separated from the current collector in a pure form, thus maintaining purity while improving productivity.
Solution Approach 2:
The patent extracts the aluminum current collector from the positive electrode structure using alkaline solution, separating it from the active material in advance. This extraction eliminates the need for pre-washing to remove current collector residues, resolving the contradiction between purity and productivity.
3Strength
If high-strength single-particle oxide is used, then particle breakage is reduced, but recovery difficulty increases
Solution Approach 1:
The patent uses alkaline solution as an intermediary medium that selectively reacts with the aluminum current collector without affecting the high-strength single-particle oxide. This allows the strong particles to be easily separated from the dissolved aluminum matrix, resolving the contradiction between particle strength and recovery ease.
Solution Approach 2:
The patent applies local quality by selectively targeting the aluminum current collector for dissolution while leaving the active material particles intact. The alkaline solution acts locally on the aluminum bonds, enabling easy separation of strong particles without compromising their integrity, thus resolving the contradiction between particle strength and recovery ease.
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
The method achieves environmentally friendly recycling with reduced costs, no waste metal elements, and no risk of explosion, while maintaining excellent battery performance and productivity.
Implementation Method 1
the positive electrode active material recovered after heat treatment of a waste positive electrode is not subjected to a pre-washing process and is directly annealed through the addition of a lithium precursor
Implementation Method 2
the positive electrode active material recovered after heat treatment of a waste positive electrode
Data Source
Figure 1~2
Figure 3
AI summary
The present disclosure relates to a positive electrode active material and a recycling method thereof. More specifically, in the positive electrode active material and a recycling method thereof, the positive electrode active material is at least one type selected from a lithium nickel oxide (LNO)-based positive electrode active material, a nickel·cobalt·manganese (NCM)-based positive electrode active material, a nickel·cobalt·aluminum (NCA)-based positive electrode active material and a nickel·cobalt·manganese·aluminum (NCMA)-based positive electrode active material, in which single particles are included, a content of F is 5,700 mg/kg to 6,500 mg/kg, and/or an a-axis lattice parameter measured by an XRD analysis is 2.8753 Å to 2.8772 Å, a c-axis lattice parameter is 14.243 Å to 14.255 Å, a cell volume is 101.968 Å3 to 102.168 Å3 and a crystallite size is greater than 130 nm and equal to or less than 136 nm.