Silicon Anode Robustness via Multi-Precursor Pyrolysis
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Solution Overview
Problem
Conventional battery electrodes are costly, cumbersome, and inefficient, limiting battery lifetime due to brittleness and structural degradation during volume changes in silicon-dominant anodes, which compromises their robustness and performance.
Innovation Solution
The use of multiple carbon precursors with different pyrolysis temperatures, such as polyimide (PI) and polyamide-imide (PAI), to enhance the flexibility, adhesion, and cohesion of silicon-based anode electrodes, allowing for improved robustness and electrical conductivity while maintaining high energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional single-carbon-precursor approaches are used, then manufacturing is simpler, but electrode robustness and battery lifetime are limited due to brittleness during volume changes
Solution Approach 1:
The patent uses composite carbon precursor materials consisting of multiple carbon precursors with different pyrolysis temperatures. This composite approach creates a multi-phase carbon structure that combines the benefits of each precursor type, providing both flexibility and conductivity while resolving the brittleness issue in single-precursor systems.
Solution Approach 2:
The patent applies different carbon precursors to different regions or phases of the electrode structure. By having carbon precursors with different pyrolysis temperatures, the electrode develops localized properties where some regions provide flexibility (from lower-temperature precursors) and others provide conductivity (from higher-temperature precursors), optimizing overall performance.
2Quantity of substance
If silicon-based anodes with high capacity are used, then energy density is improved, but structural degradation and cracking occur during volume changes
Solution Approach 1:
The patent changes the thermal parameters of the carbon precursor system by using multiple precursors with different pyrolysis temperatures. This parameter diversification allows the carbon matrix to undergo controlled thermal transformations that create a more resilient structure capable of accommodating silicon's volume changes without cracking.
Solution Approach 2:
The multi-precursor carbon matrix acts as a pre-formed cushioning structure that anticipates and accommodates silicon's volume expansion during lithiation. The flexible phases formed from lower-temperature precursors provide a buffer that prevents structural degradation before it occurs.
3Reliability
If fully pyrolyzed carbon precursors are used, then electrical conductivity is improved, but flexibility and adhesion are reduced
Solution Approach 1:
The patent segments the carbon precursor system into multiple components with different pyrolysis temperatures. This segmentation allows different portions of the carbon matrix to fulfill different functions: higher-temperature precursors form conductive phases while lower-temperature precursors maintain flexible, adhesive phases, avoiding the need to fully pyrolyze all carbon precursors.
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
This approach results in electrodes that are more flexible and resistant to cracking, maintaining performance and safety while enabling the use of silicon-based anodes with higher volumetric and gravimetric capacities, thus enhancing the overall efficiency and lifespan of lithium-ion batteries.
Implementation Method 1
the carbon precursor materials comprise different pyrolysis temperatures
Data Source
AI summary
Systems and methods for multiple carbon precursors for enhanced battery electrode robustness may include an electrode having an active material, the active material including two or more carbon precursor materials, wherein the carbon precursor materials have different pyrolysis temperatures. A battery may include the electrode. The carbon precursor materials may include polyimide (PI) and polyamide-imide (PAI). The active material may be pyrolyzed at a temperature such that a first carbon precursor material is partially pyrolyzed and a second carbon precursor material is completely pyrolyzed. The carbon precursor materials may include two or more of PI, PAI, carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyacrylonitrile (PAN), and sodium alginate. The active material may include silicon constituting at least 50% of weight of a formed anode after pyrolysis. The active material may include silicon constituting up to 97% of weight of a formed electrode after pyrolysis.