Cathode Active Material Recycling Without Acids or Organic Solvents
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Solution Overview
Problem
Existing methods for recycling positive electrode active materials from lithium secondary batteries are environmentally harmful, costly, and lead to degradation of battery performance due to the use of acids and organic solvents, and the recycling process is inefficient.
Innovation Solution
A method for recycling positive electrode active materials that involves heat treatment, addition of a lithium precursor, milling, and surface-coating without using acids or organic solvents, adjusting the crystal structure and crystallite size to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acid is used in the recovery and recycling process, then the positive electrode active material can be recovered, but environmental pollution and wastewater treatment costs increase
Solution Approach 1:
The patent converts the harmful acid-based recycling process into a beneficial alkaline process using lithium hydroxide solution. The alkaline environment effectively dissolves aluminum current collectors while preserving the positive electrode active material, transforming an environmentally harmful process into an eco-friendly one that produces easily treatable wastewater rather than toxic acid waste.
Solution Approach 2:
The patent changes the chemical parameter of the recycling solution from acidic to alkaline (pH adjustment). By using lithium hydroxide solution instead of acid, the chemical environment is fundamentally altered to achieve selective dissolution of aluminum while maintaining the integrity of the positive electrode active material, thereby eliminating environmental pollution associated with acid usage.
2Reliability
If pre-washing process is performed, then the positive electrode active material can be cleaned, but process cost and time increase
Solution Approach 1:
The patent merges the washing step into the main recycling process by directly using the lithium hydroxide solution for both dissolution and cleaning purposes. The positive electrode active material is transferred directly from the dissolution tank to the filtration tank without intermediate washing steps, as the alkaline solution itself serves to clean the material during the dissolution process.
Solution Approach 2:
The patent extracts the pre-washing step from the traditional recycling process flow. By eliminating this separate preprocessing step and integrating cleaning functionality into the main alkaline dissolution process, the patent reduces process complexity and improves productivity without compromising material quality.
3Ease of manufacture
If organic solvent is used in the recycling process, then the positive electrode active material can be processed, but toxic gas generation and explosion risk increase
Solution Approach 1:
The patent replaces expensive and hazardous organic solvents with a cheap, safe, and environmentally friendly alternative - lithium hydroxide aqueous solution. This substitution eliminates the risks associated with organic solvents (toxic gas generation, explosion hazards) while maintaining effective processing capability, using a readily available and safe chemical medium.
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 recycles the materials efficiently and environmentally friendly, maintaining battery performance and reducing costs by avoiding decomposition and hazardous substances, with improved charging capacity and resistance characteristics.
Implementation Method 1
performing heat treatment of a waste positive electrode having a positive electrode active material layer formed on a current collector at about 300° C. to 650° C. so as to thermally decompose a binder and a conductive material
Implementation Method 2
adding a lithium precursor to the recovered positive electrode active material and annealing the positive electrode active material at about 400° C. to 1,000° C.
Data Source
AI summary
The present disclosure relates to a positive electrode active material and a recycling method thereof. 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 about 5,700 mg/kg to 6,500 mg/kg, an a-axis lattice parameter measured by an XRD analysis is about 2.8753 Å to 2.8772 Å, a c-axis lattice parameter is about 14.243 Å to 14.255 Å, a cell volume is about 101.968 Å3 to 102.168 Å3 and a crystallite size is greater than about 130 nm and equal to or less than 136 nm.