Polyurethane Electrode Binder for High-Solids Low-Viscosity Coating
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Solution Overview
Problem
The increase in solids concentration of the coating liquid used for forming electrodes leads to an increase in viscosity, which results in decreased dispersibility and operability, particularly when using a urethane-resin-containing binder.
Innovation Solution
A binder composition comprising an aqueous dispersion of polyurethane resin with specific particle size distribution (D50 of 0.01 µm to 0.05 µm and D90 of 0.10 µm to 0.15 µm) is used, optionally with carbon nanotubes and carboxymethyl cellulose, to inhibit viscosity increase even at high solids concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the solids concentration of the coating liquid is increased, then the productivity and electrode performance are improved, but the viscosity of the coating liquid increases, resulting in decreased dispersibility and operability
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution parameters (D50 and D90) of the polyurethane resin. By optimizing these physical parameters within specific ranges, the binder composition achieves low viscosity even at high solids concentrations (40-60 wt%), resolving the contradiction between productivity and ease of operation
Solution Approach 2:
The patent uses a composite binder composition comprising polyurethane resin particles with specific size distribution, carbon nanotubes, and carboxymethyl cellulose. This composite material system synergistically maintains low viscosity while achieving high solids concentration, improving both productivity and operability
2Reliability
If the solids concentration of the coating liquid is increased, then the electrode performance is improved, but the dispersibility of the coating liquid decreases due to increased viscosity
Solution Approach 1:
By changing the particle size distribution parameters of the polyurethane resin (D50: 0.01-0.05 μm, D90: 0.10-0.15 μm), the patent achieves improved dispersibility while maintaining high solids concentration, thereby ensuring both electrode performance and proper coating liquid flow
Solution Approach 2:
The patent introduces carbon nanotubes and carboxymethyl cellulose as intermediary substances that enhance dispersibility of the coating liquid components. These intermediaries prevent aggregation and maintain uniform distribution even at high solids concentrations, ensuring reliable electrode performance
Data Source
AI summary
A binder composition for an electrode and a method for producing the binder composition are provided. The binder composition can inhibit an increase in viscosity of a coating liquid for forming an electrode. A coating liquid composition for an electrode is also provided. The coating liquid composition includes the binder composition. The present invention is a binder composition for an electrode, and the binder composition includes an aqueous dispersion of a polyurethane resin. The polyurethane resin has a D50 volume average particle size of 0.01 µm or greater and 0.05 µm or less and a D90 volume average particle size of 0.10 µm or greater and 0.15 µm or less.