Positive Electrode Active Material Purification With Dehydrated Acetone
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Solution Overview
Problem
Current methods for forming positive electrode active materials in lithium-ion secondary batteries face challenges in achieving high purity, maintaining crystal structure integrity during charge and discharge cycles, and enhancing charge and discharge cycle performance.
Innovation Solution
A method involving the preparation of high-purity lithium and transition metal sources, followed by crushing and mixing using dehydrated acetone, and subsequent heating in a controlled atmosphere to form composite oxides, with optional addition of additive elements like magnesium and fluorine to stabilize the crystal structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mixing methods are used to form positive electrode active material, then the manufacturing process is simple, but the purity of the positive electrode active material is insufficient
Solution Approach 1:
The patent introduces dehydrated acetone as an intermediary substance to facilitate the mixing of lithium source and transition metal source. The acetone forms a slurry that enables thorough mixing while preventing contamination, and is subsequently removed during heating. This mediator approach resolves the contradiction by providing a simple yet effective mixing mechanism that achieves high purity without complex equipment.
Solution Approach 2:
The patent specifies precise parameter requirements: dehydrated acetone with water content of 0.03% or less, heating at 500°C or higher, and controlled atmosphere conditions. By controlling these parameters, the method achieves high purity positive electrode active material while maintaining a relatively simple process flow.
2Manufacturing precision
If high-purity materials are used and complex purification processes are applied, then the purity of positive electrode active material increases, but the manufacturing cost and process complexity increase
Solution Approach 1:
Dehydrated acetone serves as a temporary intermediary that enables thorough mixing of high-purity raw materials without introducing contaminants. The acetone is completely removed during the heating step, leaving no residue. This approach achieves high purity material with a straightforward two-step process (mixing in acetone, then heating), avoiding complex multi-stage purification procedures.
Solution Approach 2:
The patent employs an inert or controlled atmosphere during heating to prevent oxidation and contamination of the high-purity materials. By maintaining a clean environment during the critical heating phase, the method preserves material purity without requiring complex in-situ purification systems.
3Stability of the object's composition
If conventional heating methods are used, then the process is simple, but the crystal structure stability during charge and discharge cycles is insufficient
Solution Approach 1:
The patent specifies precise heating parameters: temperature of 500°C or higher, controlled atmosphere, and sufficient heating time. These parameter controls ensure complete removal of acetone and proper formation of the crystal structure, achieving stable materials without requiring complex heating equipment or multi-stage thermal processing.
Solution Approach 2:
The controlled or inert atmosphere during heating prevents oxidation and contamination, ensuring the formation of a stable crystal structure. This atmospheric control is achieved through simple means such as using a covered container or inert gas flow, avoiding complex atmosphere control systems while maintaining structural stability.
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 results in a highly purified positive electrode active material with improved charge and discharge cycle performance, increased capacity, and enhanced reliability and safety of secondary batteries.
Implementation Method 1
crushing and mixing are performed using dehydrated acetone
Implementation Method 2
a third step of heating the composite material to form a composite oxide comprising the lithium and the transition metal
Implementation Method 3
a material with a purity of greater than or equal to 99.99% is prepared as the lithium source and a material with a purity of greater than or equal to 99.9% is prepared as the transition metal source
Data Source
AI summary
A method of forming a highly purified positive electrode active material is provided. A method of forming a positive electrode active material whose crystal structure is not easily broken even when charge and discharge are repeated is provided. The method of forming a positive electrode active material including lithium and a transition metal includes a first step of preparing a lithium source and a transition metal source and a second step of crushing and mixing the lithium source and the transition metal source to form a composite material. In the first step, a material with a purity of greater than or equal to 99.99% is prepared as the lithium source and a material with a purity of greater than or equal to 99.9% is prepared as the transition metal source. In the second step, crushing and mixing are performed using dehydrated acetone.