Positive Electrode Slurry Polymer Dispersant for Graphitization Variability
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Solution Overview
Problem
Existing dispersants in secondary battery production are not suitable for slurry systems containing positive electrode active materials with different graphitization degrees, leading to agglomeration and poor dispersibility, which affects conductivity and electrochemical performance.
Innovation Solution
A polymer dispersant with specific structural units and functional groups is developed to improve dispersibility, featuring a non-polar end for suspension and polar ends for anchoring, forming a three-dimensional barrier to prevent particle aggregation and enhance dispersibility, while also improving flexibility and reducing film resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional dispersant is added to improve dispersibility, then dispersibility is improved, but the dispersant is not suitable for slurry systems containing positive electrode active materials with different graphitization degrees, resulting in poor universality
Solution Approach 1:
The patent develops a polymer dispersant with a specific molecular structure comprising a non-polar end group, a polar end group, and a middle segment with amide groups that can interact with both polar and non-polar surfaces. This multi-functional structure enables the single dispersant to effectively disperse positive electrode active materials with different graphitization degrees, eliminating the need for multiple specialized dispersants and reducing manufacturing complexity
Solution Approach 2:
The patent modifies the molecular structure parameters of the dispersant by incorporating specific functional groups (non-polar end group, polar end group, and amide-containing middle segment) with controlled lengths and compositions. These structural parameter changes enable the dispersant to adapt to varying surface properties of active materials across different graphitization degrees, achieving broad universality
2Productivity
If positive electrode active material with larger specific surface area is used, then surface activity is increased, but agglomeration is prone to occur during homogenization, affecting coating effect and conductivity
Solution Approach 1:
The polymer dispersant acts as an intermediary substance between the positive electrode active material particles and the slurry medium. The polar end group anchors to the polar surface of the active material, while the non-polar end group interacts with the non-polar medium, creating a stable interface that prevents agglomeration of high-surface-area particles during homogenization and maintains slurry stability
Solution Approach 2:
The dispersant exhibits different functional properties at different parts of its molecular structure: the polar end group provides strong anchoring to polar surfaces, the amide-containing middle segment provides steric hindrance and additional polar interactions, and the non-polar end group provides compatibility with non-polar media. This local differentiation of functional properties enables effective dispersion of high-surface-area active materials
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 polymer dispersant enhances the dispersibility of slurry systems with different graphitization degrees, increasing solid content, reducing gel phenomenon, and improving first and high temperature cycling performance of the battery.
Implementation Method 1
the carboxyl group, the ester group, the sulfo group, the sulfonate group, the phospho group or the phosphate group at one end, acting as an anchoring point, is adsorbed on a surface of a solid particle
Implementation Method 2
an amide group contained in the structural unit expressed by formula II is a polar group and can generate a strong intermolecular induction force, thereby further improving the dispersion effect of the polymer
Data Source
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AI summary
The present application provides a polymer, a preparation method, a dispersant, a positive electrode slurry, a positive electrode plate, a secondary battery, and a power consuming apparatus. The polymer includes a structure expressed by formula (I), where X includes at least one of a carboxyl group, an ester group, a sulfo group, a sulfonate group, a phospho group, and a phosphate group; X' includes a non-polar group; and L includes a structural unit expressed by formula (II), where R1 includes a C1-12 alkylene group, a C6-12 arylene group or formula (A), R2 includes a C1-12 alkylene group, a C6-12 arylene group or formula (B), and R3 includes hydrogen or a C1-3 alkyl group, where EO represents -CH2-CH2-O-, PO represents -CH(CH3)-CH2-O-, m1 and m2 are each independently an integer between 3 and 60, and n1 and n2 are each independently an integer between 0 and 60.