Low-Temperature PAI Binder for Silicon-Dominant Anodes
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Solution Overview
Problem
Conventional battery anodes are costly, cumbersome, and inefficient, limiting battery lifetime due to complex and time-consuming implementation processes, and they struggle with the large volume changes of silicon-dominant anodes that lead to electrical isolation and capacity loss.
Innovation Solution
A binder with a lower pyrolysis temperature, specifically polyamide imide (PAI), is used in silicon-dominant anodes to facilitate a direct coating or transfer lamination process, reducing anisotropic expansion and maintaining electrical conductivity, thereby improving cycle life and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional binders are used in silicon-dominant anodes, then the anode can be manufactured, but the large volume changes during cycling cause electrical isolation and capacity loss, limiting battery lifetime
Solution Approach 1:
The patent changes the pyrolysis temperature parameter from conventional high temperatures to a lower temperature range (300-500°C), which transforms the binder's physical and chemical properties to better accommodate silicon's volume changes while maintaining electrical conductivity throughout cycling
Solution Approach 2:
The patent creates a composite binder system combining polyamide imide with other materials that exhibit complementary properties, where the composite structure provides both mechanical flexibility to handle volume expansion and electrical conductivity to prevent isolation of silicon particles
2Quantity of substance
If silicon-dominant anodes are used to increase capacity, then energy density improves, but the complex and time-consuming implementation process reduces productivity
Solution Approach 1:
The patent performs preliminary actions by pre-synthesizing the low pyrolysis temperature binder and pre-designing the composite structure before anode fabrication, which simplifies the manufacturing process and reduces the time required for implementation while maintaining high silicon content for energy density
3Temperature
If conventional high pyrolysis temperature binders are used, then thermal stability is achieved, but the processing time and temperature requirements increase, making the process cumbersome
Solution Approach 1:
The patent fundamentally changes the pyrolysis temperature parameter from conventional high temperatures (>600°C) to a lower range (300-500°C), which directly reduces processing time and energy consumption while achieving sufficient thermal stability for battery operation through the unique molecular structure of polyamide imide
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 use of a PAI binder with a lower pyrolysis temperature enhances the discharge capacity and cycle performance of silicon-dominant anodes by reducing expansion and maintaining electrical contact, leading to improved battery performance and longevity.
Implementation Method 1
A binder with a lower pyrolysis temperature, specifically polyamide imide (PAI), is used in silicon-dominant anodes
Data Source
AI summary
Systems and methods are provided for carbon additives for direct coating of silicon-dominant anodes. An example composition for use in directly coated anodes may include a silicon-dominated anode active material, a carbon-based binder, and a carbon-based additive, with the composition being configured for low-temperature pyrolysis. The low-temperature pyrolysis may be conducted at <600° C. An anode may be formed using a direct coating process of the composition on a current collector. The anode active material yields silicon constituting between 86% and 97% of weight of the formed anode after pyrolysis. The carbon-based additive yields carbon constituting between 2% and 6% of weight of the formed anode after pyrolysis.