Aqueous Electrode Binder Composition for Stronger Anode Adhesion
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Solution Overview
Problem
Existing binders for lithium ion batteries, such as styrene butadiene rubber/carboxymethyl cellulose, exhibit low adhesion with active materials, particularly when used in large devices like electric automobiles and power storage systems, failing to meet the requirements for high safety, extended cycle life, and high energy density.
Innovation Solution
Aqueous binder compositions comprising a cationic copolymer derived from cationic and nonionic monomers, combined with anionic polymers and conductive agents, are used to form electrodes with improved adhesion and stability, utilizing materials like silicon and lithium-containing transition metal oxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing binders such as styrene butadiene rubber/carboxymethyl cellulose are used, then the electrode film can be formed on the current collector, but the adhesion strength between the film and current collector is insufficient
Solution Approach 1:
The patent changes the chemical parameters of the binder by using a copolymer with specific functional groups (carboxyl, hydroxyl, amine groups) and controlled molecular weight (10,000-1,000,000 g/mol). The binder contains 1-50 monomer units with specific ratios of functional monomers (1-50 mol%) to non-functional monomers, creating optimal chemical parameters for adhesion to silicon-based active materials while maintaining film-forming capability.
Solution Approach 2:
The patent employs a composite binder system consisting of a copolymer made from multiple monomer types (functional monomers providing adhesion sites and non-functional monomers providing structural backbone). This composite structure combines the adhesive properties of functional groups with the mechanical strength of the polymer matrix, achieving both strong adhesion and reliable electrical contact.
2Strength
If new aqueous binder composition with improved adhesion is developed, then the adhesion strength and contact reliability are enhanced, but the binder composition complexity increases
Solution Approach 1:
The patent optimizes specific parameters of the copolymer including molecular weight (10,000-1,000,000 g/mol), functional monomer content (1-50 mol%), and the ratio of different functional groups. These controlled parameter changes allow tuning of adhesion properties without requiring complex multi-component systems, simplifying the overall composition while achieving superior performance.
3Duration of action of stationary object
If existing binders are used with silicon-based anode materials, then the electrode can be manufactured, but the cycle life and energy density requirements for electric vehicles are not met
Solution Approach 1:
The patent uses a copolymer with controlled molecular weight (10,000-1,000,000 g/mol) and specific functional group content (1-50 mol% functional monomers) to achieve optimal balance between adhesion strength for long cycle life and flexibility for high energy density silicon-based electrodes. The functional groups provide strong binding to silicon while the polymer structure accommodates silicon's volume expansion.
Solution Approach 2:
The composite copolymer structure combines functional monomers (providing adhesion and chemical stability for extended cycle life) with non-functional monomers (providing mechanical flexibility and energy density). This composite approach enables the binder to simultaneously meet the conflicting requirements of long-term durability and high energy storage capacity.
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 compositions enhance electrode adhesion, ensuring stable contact with current collectors, thereby improving the performance and safety of lithium ion batteries, particularly in large-scale applications.
Implementation Method 1
an aqueous binder composition comprising a cationic copolymer derived from at least one cationic monomer and at least one nonionic monomer
Implementation Method 2
combined with anionic polymers and a conductive agent, is used to form a slurry with electrode active materials, enhancing adhesion and stability on current collectors
Data Source
AI summary
An aqueous binder composition comprising a cationic copolymer derived from at least one cationic monomer and at least one nonionic monomer is disclosed. Additionally, the present disclosure relates generally to electrode compositions and methods of making electrodes, especially anodes, with the binder composition.