Spent Cathode Binder Removal by Water-Oil Phase Separation
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Solution Overview
Problem
Conventional methods for recycling cathode active materials from spent lithium-ion batteries are inefficient, environmentally harmful, and damage the material's morphology, leading to low purity and yield, especially when the battery is deeply cycled.
Innovation Solution
An oil agglomeration method involving mixing spent cathode active material with water, grinding to separate the binder, and then agitating with oil to form distinct oil and water phases, allowing for effective separation of the binder from the cathode active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional solvents are used to separate cathode active material from binder, then separation can be achieved, but the process becomes expensive and environmentally harmful
Solution Approach 1:
The patent replaces expensive conventional solvents with water, which is a cheap, non-toxic, and environmentally friendly alternative. Water serves as the separation medium to remove the binder from cathode active material particles without the harmful environmental effects associated with traditional organic solvents
Solution Approach 2:
The patent changes the chemical parameter of the separation medium from organic solvents to water, fundamentally altering the separation mechanism while achieving effective binder removal. This parameter change enables environmentally benign processing while maintaining separation efficiency
2Manufacturing precision
If high temperature hydrothermal treatment is used to remove binder, then binder removal can be achieved, but the morphology of cathode active material is destroyed
Solution Approach 1:
The patent replaces the thermal mechanism (high temperature hydrothermal treatment) with a mechanical separation mechanism involving water mixing and grinding. This substitution allows binder removal through physical separation rather than thermal degradation, preserving the morphology of cathode active material particles
Solution Approach 2:
The patent introduces water as an intermediary medium that facilitates binder removal through mechanical mixing and grinding processes. Water acts as a lubricant and separation medium, enabling the binder to be detached and removed without subjecting the cathode active material to destructive high temperatures
3Productivity
If conventional direct recycling methods are used, then some binder removal can be achieved, but the purity and yield of cathode active material remain low
Solution Approach 1:
The patent applies preliminary grinding to the cathode active material particles before the main separation process. This preliminary action breaks up aggregates and exposes more binder surface area, making the subsequent water-based separation more effective and resulting in higher purity and yield of recovered cathode active material
Solution Approach 2:
The patent employs a continuous multi-step process involving mixing, grinding, and separation that maintains continuous action on the material. This continuous processing ensures thorough binder removal while maximizing the recovery of cathode active material, achieving both high purity and high yield
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 achieves high purity and yield of cathode active material, preserving its morphology and reducing environmental impact, without the need for conventional solvents.
Implementation Method 1
mixing the first mixture with a hydrocarbon liquid, agitating the hydrocarbon liquid and the first mixture and forming an oil phase and a water phase, and separating the oil phase from the water phase
Implementation Method 2
agitating the hydrocarbon liquid and the first mixture and forming an oil phase and a water phase
Implementation Method 3
The spent cathode active material includes cathode active material particles and the binder
Data Source
AI summary
A method is provided for removing a binder from a spent cathode active material. The method includes mixing the spent cathode active material with water to form a first mixture. The spent cathode active material includes cathode active material particles and the binder. The method further includes grinding the first mixture to separate the binder from the cathode active material particles, mixing the first mixture with a hydrocarbon liquid, agitating the hydrocarbon liquid and the first mixture and forming an oil phase and a water phase, and separating the oil phase from the water phase. The first mixture contains the cathode active material particles, the binder and the water. The oil phase contains the hydrocarbon liquid and the binder, and the water phase contains the cathode active material particles and the water.