Polymer Dispersant for High-Solid Positive Electrode Slurries
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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, necessitating a dispersant that can adapt to different graphitization levels.
Innovation Solution
A polymer dispersant with specific structural units and functional groups is developed, forming a three-dimensional barrier to prevent particle aggregation and enhance dispersibility, flexibility, and reduce film resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional dispersant is added to improve the dispersibility of slurry containing positive electrode active materials with different graphitization degrees, then the dispersibility is improved, but the universality is poor and manufacturing cost increases
Solution Approach 1:
The patent develops a polymer dispersant with a specific molecular structure comprising a polyether backbone (providing flexibility and adaptability to different graphitization degrees) combined with polar functional groups (carboxyl, hydroxyl, or amine groups at both ends) that can universally interact with various positive electrode active materials regardless of their graphitization level. This multi-functional structure enables the dispersant to effectively disperse materials with different surface properties while maintaining a single formulation across varying material batches.
2Stability of the object's composition
If a conventional dispersant is used, then the dispersibility is improved, but particle aggregation still occurs forming larger aggregates
Solution Approach 1:
The patent utilizes parameter changes at the molecular level by incorporating a polyether backbone with adjustable chain length and composition (combining EO and PO units in varying ratios) to optimize the steric hindrance and solvation effects. The polar functional groups at both ends of the polymer chain provide enhanced adsorption capability to particle surfaces, creating a stronger protective barrier that prevents aggregate formation more effectively than conventional single-end functionalized dispersants.
3Quantity of substance
If the slurry solid content is increased to improve battery performance, then the electrochemical performance is improved, but the gel phenomenon occurs more rapidly
Solution Approach 1:
The polymer dispersant provides continuous and sustained steric stabilization through its flexible polyether backbone that maintains extended conformation in the slurry medium. The dual polar functional groups ensure continuous adsorption onto particle surfaces, creating a persistent protective barrier that prevents particle-particle contact and delays the gel transition even at high solid contents, thereby extending the useful processing window of the slurry.
4Ease of operation
If the electrode plate flexibility is improved to enhance battery performance, then the first coulombic efficiency is improved, but the film resistance increases
Solution Approach 1:
The patent employs local quality differentiation in the dispersant structure: the polyether backbone segments (particularly the EO units) provide flexibility and adaptability to maintain electrode plate bendability, while the polar functional groups at both ends provide strong surface adsorption to ensure good electrical contact and low film resistance. This spatial differentiation of functional properties within the single polymer molecule allows simultaneous optimization of both flexibility and conductivity.
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 improves the dispersibility and flexibility of electrode plates, enhances the solid content of the slurry, and increases the first coulombic efficiency and high-temperature cycling performance of batteries, reducing manufacturing costs.
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
AI summary
A polymer, a preparation method, a dispersant, a positive electrode slurry, a positive electrode plate, a secondary battery, and a power consuming apparatus are disclosed. 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.