Silicon Anode Binder Composition for Swelling-Resistant Cycling
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Solution Overview
Problem
Lithium-ion batteries using silicon-based materials face significant challenges due to severe volume swelling during cycling, leading to particle pulverization, detachment from the current collector, and poor cycling performance.
Innovation Solution
A negative electrode plate design incorporating a silicon-based material with a binder containing functional groups like hydroxyl, carboxyl, amino, cyano, or vinyl, which enhances adhesion and cohesion, mitigating volume swelling and reducing demolding and powder shedding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If silicon-based material is used as negative electrode active material, then energy density is improved, but volume swelling occurs during cycling
Solution Approach 1:
The binder forms a flexible film matrix that envelops silicon-based particles, allowing the structure to flex and accommodate volume changes during lithium insertion/extraction cycles. This flexible film constraint prevents particle pulverization while maintaining electrical contact.
Solution Approach 2:
The negative electrode is constructed as a composite material system combining silicon-based active material particles with a polymer binder matrix. This composite structure leverages the high capacity of silicon while the binder provides structural stability and volume buffering.
2Volume of stationary object
If silicon-based material with irregular particle shapes is used, then porosity is improved, but adhesion deteriorates
Solution Approach 1:
The binder acts as an intermediary material that fills the gaps between irregular silicon particles and bonds them to the current collector. This intermediary substance creates strong adhesive bonds despite the irregular geometry of the active material particles.
Solution Approach 2:
The binder is strategically positioned in the interstices between silicon particles and at the interface with the current collector, providing localized adhesion enhancement where it is most needed while maintaining overall electrode porosity for ion transport.
3Strength
If binder with good adhesion is added, then cohesion is improved, but demolding and powder shedding occur without proper binder
Solution Approach 1:
The binder contains functional groups (carboxyl, hydroxyl, amino, cyano, or vinyl) that can undergo chemical reactions or strong interactions with silicon surfaces and current collector materials. This chemical functionality dramatically enhances adhesion parameters and prevents electrode disintegration during cycling.
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 improves the cycling performance of lithium-ion batteries by suppressing volume swelling and enhancing adhesion between the silicon-based material and the current collector, thereby reducing demolding and powder shedding.
Implementation Method 1
the binder including at least one functional group selected from hydroxyl, carboxyl, amino, cyano, ester, or vinyl has good adhesion. Adding a binder with good adhesion to the negative electrode film layer allows the binder to fill the large pores of the silicon-based material
Data Source
AI summary
Embodiments of this application provide a negative electrode plate, a battery cell, a battery, and an electric apparatus. The negative electrode plate includes a negative electrode current collector and a negative electrode film layer disposed on at least one side of the negative electrode current collector; where the negative electrode film layer includes a negative electrode active material and a binder, the negative electrode active material includes a silicon-based material, and the binder includes at least one of the following functional groups: hydroxyl, carboxyl, amino, cyano, ester, or vinyl. The technical solution of this application can improve cohesion and adhesion of the negative electrode plate, reducing powder shedding and demolding during production, thereby enhancing cycling performance of the battery.