Anionic Anode Binder Composition for High-Silicon Cycle Stability
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Solution Overview
Problem
Existing anode compositions in batteries face challenges such as non-uniform application, mechanical weakness, strain tolerance issues due to silicon expansion, and inadequate compatibility among ingredients, which affect the performance and stability of anodes.
Innovation Solution
An aqueous anode composition using a water-soluble anionic copolymer binder prepared from (meth)acrylic acid and (meth)acrylate monomers, with specific molecular weight and pH ranges, applied uniformly to form a stable and conductive layer on a substrate, incorporating materials like carbon graphite and silicon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If styrene-butadiene polymer binding composition is used, then particles can be fixed on metal substrate, but mechanical strength and electrochemical resistance are insufficient
Solution Approach 1:
The patent changes the chemical parameters of the binding composition by using water-soluble anionic polymers with specific molecular weights (10,000-1,000,000 g/mol) and controlled architecture (linear, branched, or cross-linked). This replaces the conventional styrene-butadiene polymer and achieves both improved mechanical strength and electrochemical resistance through optimized polymer structure and composition
Solution Approach 2:
The patent creates a composite binding system combining water-soluble anionic polymers with specific additives (thickening agents, dispersing agents, wetting agents) to achieve synergistic effects. This composite approach provides both the mechanical strength needed for particle fixation and the electrochemical resistance required for battery performance
2Manufacturing precision
If conventional binding compositions are used, then particles can be bound to substrate, but application uniformity is poor and surface flaws occur
Solution Approach 1:
The patent introduces water-soluble anionic polymers as intermediary binding agents that facilitate uniform distribution of carbon and metal particles on the substrate. These polymers act as mediators between the particles and substrate, enabling smooth, flaw-free application through their water solubility and anionic characteristics that promote even coating
Solution Approach 2:
The patent modifies the rheological parameters of the binding composition by selecting polymers with specific molecular weights and architectures, and by adding thickening and dispersing agents. This optimization ensures uniform viscosity and flow characteristics during application, preventing surface flaws and achieving consistent coating quality
3Quantity of substance
If silicon is added to increase capacity, then battery capacity increases, but strain tolerance decreases due to volume expansion
Solution Approach 1:
The patent employs water-soluble anionic polymers with high elasticity and adhesion as a cushioning matrix that accommodates the volume expansion of silicon during lithiation. This binding composition is designed beforehand to absorb and distribute the mechanical strain, preventing particle detachment and maintaining structural integrity throughout charge-discharge cycles
Solution Approach 2:
The patent creates a composite structure where silicon particles are embedded in a flexible polymer matrix containing water-soluble anionic polymers. This composite approach allows the polymer to compensate for silicon volume changes while maintaining electrical conductivity and mechanical strength, achieving both high capacity and strain tolerance
4Reliability
If multiple additives are used in binding composition, then binding performance improves, but ingredient compatibility becomes problematic
Solution Approach 1:
The patent uses water-soluble anionic polymers as a homogeneous base that ensures compatible interaction with all other ingredients (carbon particles, metal particles, additives). This uniform polymer matrix prevents phase separation and incompatibility issues, allowing all components to work together synergistically without precipitation or aggregation
Solution Approach 2:
The patent optimizes the ionic characteristics and molecular weight parameters of the polymer to achieve compatibility across different particle types and additives. By controlling the charge density and chain length, the binding composition maintains stability and compatibility with various silicon, carbon, and metal components under different pH and electrolyte conditions
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 solution provides anodes with enhanced mechanical strength, uniformity, and improved electrochemical performance, supporting high silicon concentrations and stable charge-discharge cycles.
Implementation Method 1
The binding composition must be able to effectively bind the carbon or the metal to a substrate to form an anode
Implementation Method 2
a water-soluble polymer P, with a weight-average molecular mass Mw (measured by SEC) ranging from 2,000 g/mol to 1,000,000 g/mol, prepared in the presence of at least one initiator compound, by a polymerisation reaction of
Data Source
AI summary
An aqueous anode composition including metal particles or fibres or carbon graphite particles or fibres, and a binding agent including at least one water-soluble polymer P prepared on the basis of (meth)acrylic acid and (meth)acrylate. A method for producing an anode including said aqueous composition.