High-Nickel Cathode Recycling With Two-Step Oxidation Purification
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Solution Overview
Problem
Current methods for recycling positive electrode active materials from waste lithium secondary batteries are inefficient, often resulting in degraded battery characteristics, environmental pollution, and high costs due to the use of acids and organic solvents.
Innovation Solution
A method involving the introduction of oxygen into a waste positive electrode with a high-nickel positive electrode material, followed by oxidation heat treatment in two steps to burn the binder, reduce fluorine and residual lithium, and decrease crystallite size, combined with first and second washing steps to remove impurities, and the addition of a lithium precursor for annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If acid dissolution method is used to extract rare metals from waste positive electrode, then rare metals can be recovered, but neutralization process and wastewater treatment are required which greatly increases process costs
Solution Approach 1:
The patent converts the harmful acid dissolution process into a beneficial direct recycling process. Instead of using acids to dissolve the positive electrode material, the invention directly recycles the positive electrode active material through thermal treatment and mechanical separation, converting the waste material directly into reusable components without harmful chemical reactions.
Solution Approach 2:
The patent extracts and removes the binder and conductive additives from the positive electrode through thermal treatment at 200-400°C, separating the valuable positive electrode active material from the waste components. This extraction process eliminates the need for acid dissolution while recovering the functional material.
2Device complexity
If direct recycling method is used to recycle positive electrode active material without disassembling, then no metal element is discarded and process is simplified, but binder and conductive additives remain mixed with the active material
Solution Approach 1:
The patent performs preliminary thermal treatment at 200-400°C to decompose and remove the binder and conductive additives before the main recycling process. This preliminary action eliminates impurities in advance, allowing the positive electrode active material to be recovered in a purified state without requiring complex disassembly or separation procedures.
3Device complexity
If oxidation heat treatment is performed in one step, then process is simpler, but binder cannot be completely burned and fluorine and residual lithium remain high
Solution Approach 1:
The patent segments the heat treatment process into two distinct stages: first heating to 200-400°C to remove binder and conductive additives, then heating to 400-600°C to remove fluorine and residual lithium. This segmentation allows each thermal treatment step to be optimized for specific removal targets, achieving complete impurity elimination while maintaining process simplicity.
4Quantity of substance
If conventional recycling methods are used, then positive electrode active material can be recovered, but battery characteristics are degraded and capacity characteristics deteriorate
Solution Approach 1:
The patent optimizes multiple process parameters including thermal treatment temperature (200-600°C), oxygen concentration (5-50%), and heat treatment time to achieve complete removal of impurities while preserving the crystal structure and electrochemical properties of the positive electrode active material. These parameter changes ensure the recovered material maintains excellent battery performance and capacity characteristics.
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 a recycled positive electrode active material with excellent capacity, resistance, and capacity characteristics, while ensuring eco-friendliness by avoiding acid use, reducing process costs, and improving economic feasibility and productivity.
Implementation Method 1
introducing oxygen into a waste positive electrode containing a high-nickel (Ni) positive electrode material, performing oxidation heat treatment
Implementation Method 2
completely burn a binder
Implementation Method 3
adding a lithium precursor, performing annealing
Data Source
AI summary
The present disclosure relates to a recycled positive electrode active material, a method of producing the recycled positive electrode active material, and a secondary battery including the same. The recycled positive electrode active material, including: 60 mol % or more of Ni, 250 mg/kg or less of fluorine (F), and having a crystallite size of 122 nm or less, where the recycled positive electrode active material is one or more selected from the group consisting of 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.