Electrode Agglomerate Formation for Homogeneous Li-Ion Conductivity
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Solution Overview
Problem
Lithium-ion batteries face challenges with poor homogeneity of conductive additives in electrodes, leading to undesirable agglomerations and poor electrical contact, which negatively impact power capabilities and cycling stability.
Innovation Solution
A method for forming electrodes by contacting precursor electroactive material with conductive materials and a polymeric solution, applying mixing forces, and drying to create electroactive material agglomerates, followed by additional processing steps to ensure uniform dispersion of conductive and binder materials, enhancing electrical connectivity and material utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If common methods are used to prepare electrodes with conductive additives, then the manufacturing process is simple, but the homogeneity of conductive additive is poor leading to agglomerations and poor electrical contact
Solution Approach 1:
The electrode preparation process is divided into multiple sequential stages: first forming agglomerates with initial mixing and drying, then dispersing these agglomerates in a second solvent with different properties. This segmentation allows each stage to optimize for its specific function - agglomerate formation for conductivity and dispersion for homogeneity.
Solution Approach 2:
The invention changes key parameters between mixing stages by switching solvents with different properties (first solvent for agglomerate formation, second solvent for dispersion). This parameter change enables the system to achieve both good electrical contact through agglomerates and homogeneous distribution through the dispersion stage.
2Reliability
If conductive additives are added to electrodes, then electrical conductivity is improved, but agglomerations occur leading to poor homogeneity
Solution Approach 1:
The conductive additive is segmented into agglomerates first, then these agglomerates are uniformly dispersed in the electrode slurry. This two-stage approach ensures that conductive particles are clustered for conductivity while the clusters themselves are evenly distributed for homogeneity.
Solution Approach 2:
The invention uses binder materials and solvents as intermediaries to mediate between conductive additives and the electrode matrix. The binder encapsulates conductive particles in agglomerates, while the solvent system controls the dispersion of these agglomerates, achieving both conductivity and homogeneity.
3Quantity of substance
If agglomerations of electroactive material occur, then material concentration is increased, but electrical contact between particles is poor
Solution Approach 1:
The invention changes the physical state and distribution parameters of electroactive material through controlled agglomeration followed by uniform dispersion. The material is concentrated in agglomerates but these agglomerates are evenly distributed with proper spacing, maintaining both high local concentration and good electrical contact.
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 improves the homogeneity and electrical connectivity of electrodes, leading to enhanced power capabilities and cycling stability, addressing the issues of agglomerations and poor electrical contact.
Implementation Method 1
a polymeric solution including a first solvent and a binder material to form a first admixture; applying a mixing force to the first admixture to form a first mixture; drying the first mixture to form a plurality of electroactive material agglomerates, each agglomerate including an electroactive material particle in contact with the conductive material via the binder material
Implementation Method 2
contacting the plurality of electroactive material agglomerates to a second solvent to form a second admixture, the binder material being insoluble in the second solvent
Data Source
AI summary
A method for forming an electrode for an electrochemical cell that cycles lithium ions is provided. The method includes contacting a precursor electroactive material and a conductive material to a polymeric solution including a first solvent and a binder material to form a first admixture; applying a mixing force to the first admixture to form a first mixture; drying the first mixture to form a plurality of electroactive material agglomerates, each agglomerate including an electroactive material particle in contact with the conductive material via the binder material; contacting the plurality of electroactive material agglomerates to a second solvent to form a second admixture, the binder material being insoluble in the second solvent; applying a mixing force to the second admixture to form a second mixture; and disposing the second mixture on or near one or more surfaces of a current collector to form the electrode.