Electrode Binder Composition for Stable One-Step Li-Ion Slurry Mixing
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Solution Overview
Problem
Current binders for lithium ion batteries require multi-step processes, are costly, and unstable, especially when using styrene butadiene latex, which complicates the production of lithium ion battery electrodes and affects their performance, particularly with materials like silicon that undergo volume changes during charging and discharging.
Innovation Solution
A binder composition comprising an ionizable water-soluble polymer, a redispersible powder with a protective colloid and an anticaking agent, allowing for a single-step mixing process that improves adhesion and electrochemical properties, specifically using carboxymethyl hydroxyethyl cellulose for enhanced flexibility and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If styrene butadiene latex is used as binder, then adhesion properties are improved, but stability deteriorates due to temperature sensitivity and biocide requirements
Solution Approach 1:
The patent uses a composite binder system combining carboxymethyl cellulose (CMC) with styrene butadiene latex. The CMC provides temperature stability and adhesion while the latex enhances binding strength. This composite approach allows the binder to maintain stability across temperature ranges without requiring biocides, while still achieving strong adhesion to the electrode active material and current collector.
2Reliability
If multi-step mixing process is used with cellulosic material and latex, then binder performance is improved, but production time and cost increase
Solution Approach 1:
The patent merges the cellulosic material (carboxymethyl cellulose) and latex components into a single pre-mixed binder composition that can be added to the electrode slurry in one step. This unified binder formulation eliminates the need for separate mixing steps for cellulosic material and latex, reducing production time and complexity while maintaining the performance benefits of both components working together.
3Ease of operation
If styrene butadiene latex is stored at room temperature, then ease of storage is improved, but stability deteriorates requiring biocides
Solution Approach 1:
The patent replaces the unstable styrene butadiene latex with carboxymethyl cellulose, a water-soluble polymer that is inherently stable at room temperature without requiring biocides. While CMC alone has limitations in adhesion, the patent combines it with latex in a pre-mixed binder composition that provides both the stability of CMC and the adhesion benefits of latex, eliminating the need for biocide addition and simplifying storage requirements.
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 new binder composition reduces production costs and time, enhances the electrochemical performance of lithium ion batteries by improving adhesion and capacity retention, even with materials like silicon that experience volume changes, and is stable across various temperatures.
Implementation Method 1
the binder plays an important role in the performance of lithium ion batteries... sufficient adhesive and chemical properties such that the film coated on the current collector will maintain contact with the current collector
Implementation Method 2
specifically using carboxymethyl hydroxyethyl cellulose for enhanced flexibility and capacity retention... materials like silicon that undergo volume changes during charging and discharging
Data Source
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AI summary
The presently disclosed and/or claimed inventive process(es), procedure(s), method{s), product(s), result(s), and/or concept(s) (collectively hereinafter referred to as the "presently disclosed and/or claimed inventive concept(s)") relates generally to the composition of a binder for use in battery electrodes and methods of preparing such. More particularly, but not by way of iimitation, the presently disclosed and/or claimed inventive concept(s) relates to a binder composition containing an ionizable water soluble polymer and a redispersible powder containing a latex, a protective colloid, and an anticaking agent for use in the production and manufacture of electrodes of a lithium ion battery. Additionally, the presently disclosed and/or claimed inventive concept(s) relates generally to the compositions and methods of making electrodes, both anodes and cathodes, with a binder composition containing an ionizable water soluble polymer and a redispersible powder.