Recycled Cathode Active Material Polishing for Capacity Recovery
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Solution Overview
Problem
Existing methods for recycling degraded positive electrode active materials in lithium-ion batteries require high energy consumption and high costs, and fail to effectively recover capacity and reduce increased resistance due to structural changes during charge-discharge cycles.
Innovation Solution
A manufacturing method involving polishing of the positive electrode active material to separate a rock salt crystal structure coating from a core particle, using XAFS analysis to evaluate the effectiveness of the polishing, thereby recovering capacity and reducing resistance without baking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If baking is used to treat degraded positive electrode active material, then crystallite size can be grown to sufficient size, but energy consumption increases and cost increases
Solution Approach 1:
The patent changes the treatment parameters from high-temperature baking (750-1000°C) to low-temperature polishing treatment. By controlling the polishing conditions (polishing time, polishing medium, particle size of polishing agent), the rock salt coating is selectively removed without requiring high energy input, thus resolving the contradiction between performance recovery and energy consumption.
Solution Approach 2:
The patent replaces the thermal field (baking) with a mechanical field (polishing). Instead of using heat to treat the degraded material, a mechanical polishing process is employed to physically remove the harmful rock salt coating layer, thereby reducing energy consumption while achieving the desired treatment effect.
2Reliability
If baking at high temperature is performed, then crystallite size grows sufficiently, but manufacturing cost increases
Solution Approach 1:
The patent changes the treatment parameters from high-temperature baking (750-1000°C) to low-temperature polishing treatment. By controlling the polishing conditions (polishing time, polishing medium, particle size of polishing agent), the rock salt coating is selectively removed without requiring high energy input, thus resolving the contradiction between performance recovery and energy consumption.
Solution Approach 2:
The patent replaces the thermal field (baking) with a mechanical field (polishing). Instead of using heat to treat the degraded material, a mechanical polishing process is employed to physically remove the harmful rock salt coating layer, thereby reducing energy consumption while achieving the desired treatment effect.
3Stability of the object's composition
If the rock salt coating is not removed, then the material structure is preserved, but capacity recovery is prevented and resistance remains high
Solution Approach 1:
The patent applies segmentation by differentiating between the core layered structure (to be preserved) and the surface rock salt coating (to be removed). The polishing process selectively targets the surface coating while leaving the underlying layered structure intact, thus resolving the contradiction between structure preservation and performance recovery.
Solution Approach 2:
The patent applies local quality by treating only the surface layer of the material. The polishing process is designed to remove the rock salt coating from the surface while preserving the bulk layered structure, achieving different outcomes for different regions of the same material.
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 effectively recovers the capacity of degraded positive electrode active materials and reduces response resistance, achieving high-quality recycled materials for new lithium-ion batteries.
Implementation Method 1
polishing the positive electrode active material, wherein at least a part of the coating part is separated from the core particle by the polishing
Implementation Method 2
a ratio (IB/IA) of a peak strength IA at 8341 eV on a nickel (Ni)—K absorption edge measured by an XAFS analysis on the positive electrode active material before the polishing and a peak strength IB at the 8341 eV on the nickel (Ni)—K absorption edge measured by the XAFS analysis on the positive electrode active material after the polishing
Data Source
AI summary
Provided is a technique to recover a capacity of a degraded positive electrode active material and to reduce a response resistance increased by the degradation without using a means for baking. A manufacturing method disclosed herein includes polishing the positive electrode active material. The positive electrode active material includes a core particle having a layered crystal structure and includes a coating part having a rock salt crystal structure on a surface of the core particle. A ratio (IB/IA) of a peak strength IA at 8341 eV on a nickel (Ni)—K absorption edge measured by a XAFS analysis on the positive electrode active material before the polishing and a peak strength IB at the 8341 eV on the nickel (Ni)—K absorption edge measured by the XAFS analysis on the positive electrode active material after the polishing becomes equal to or less than 0.7.