Polymer Dispersant for Positive Electrode Slurry Agglomeration Control
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Solution Overview
Problem
Existing dispersants for secondary battery positive electrode slurries are not suitable for materials with varying graphitization degrees, leading to agglomeration, reduced conductivity, and poor electrochemical performance.
Innovation Solution
A polymer dispersant with specific structural units and functional groups is developed to improve dispersibility and flexibility, featuring a three-dimensional barrier and intermolecular induction forces, suitable for positive electrode active materials with different graphitization degrees.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a dispersant is added to improve dispersibility of slurry containing positive electrode active materials with different graphitization degrees, then dispersibility is improved, but the universality of the dispersant is poor and manufacturing cost increases
Solution Approach 1:
The patent develops a polymer dispersant with a specific molecular structure comprising a non-polar group, a polar group, and a carbamate or carbamate-like group that can effectively disperse positive electrode active materials with different graphitization degrees (10%-30%). This single dispersant formulation achieves universal applicability across materials produced through different processes, eliminating the need for multiple specialized dispersants and reducing manufacturing complexity
2Quantity of substance
If nano-scale positive electrode active material is used to increase specific surface area, then surface activity is improved, but agglomeration occurs during homogenization resulting in larger aggregates
Solution Approach 1:
The polymer dispersant acts as an intermediary substance between nano-scale positive electrode active materials and the slurry medium. Its molecular structure with non-polar, polar, and carbamate groups provides multiple interaction mechanisms that prevent agglomeration of high-surface-area particles during homogenization, maintaining particle dispersion without requiring changes to the nano-material itself
Solution Approach 2:
The patent modifies the chemical and physical parameters of the dispersant by incorporating specific functional groups (carbamate or carbamate-like groups) and controlling molecular weight (1500-65000 g/mol) and hydrophilic-lipophilic balance (6-16). These parameter optimizations enable the dispersant to effectively stabilize nano-scale particles with high surface activity, preventing aggregation while maintaining the beneficial high surface area characteristics
3Ease of manufacture
If conventional dispersant is used for positive electrode active materials with different graphitization degrees, then manufacturing process is simple, but electrochemical performance and conductivity are reduced
Solution Approach 1:
The patent optimizes key parameters of the dispersant including molecular weight (1500-65000 g/mol), hydrophilic-lipophilic balance (6-16), and functional group composition (carbamate or carbamate-like groups). These parameter adjustments enhance the dispersant's ability to improve conductivity and electrochemical performance while maintaining ease of manufacture through a straightforward two-step synthesis process with 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
Enhances dispersibility, increases solid content, reduces film resistance, and improves first coulombic efficiency 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
the non-polar group at the other end is suspended in the slurry to form a three-dimensional barrier. When solid particles get close to each other, this three-dimensional barrier will generate a strong repulsive force, prevent particle aggregation
Implementation Method 3
a carbamate group or a carbamate-like 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
Implementation Method 4
L chain segments contain fewer branches, bond angles are relatively fixed, a certain linear structure is presented in the slurry system, the chain segments are completely stretched in the slurry system, the chain segments are not easily entangled, and the spatial hindrance generated thereby fully isolates the solid particles
Data Source
AI summary
Provided are 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 at least one of a C1-12 alkylene group, a C6-12 arylene group, and (I), R2 includes at least one of a C1-12 alkylene group, a C6-12 arylene group, and (II), and R3 includes hydrogen or a C1-18 alkyl group, where EO represents —CH2—CH2—O—, PO represents —CH(CH3)—CH2—O—, m1 and m2 are each independently an integer between 1 and 10, and n1 and n2 are each independently an integer between 0 and 10.