Pyrolyzed Composite Resin Active Material for Battery Negative Electrodes
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Solution Overview
Problem
Current active materials for negative electrodes in nonaqueous secondary batteries, such as carbon-based and metal alloy-based materials, face limitations in energy density and stability, leading to issues like electrode peeling and reduced battery performance due to low interface adhesion and complex manufacturing processes.
Innovation Solution
A composite resin with a silanol group and/or hydrolysable silyl group, containing a polysiloxane segment and a vinyl polymer segment, is pyrolyzed to create an active material with improved electrical conductivity and cycle characteristics for negative electrodes, enhancing the stability and performance of nonaqueous secondary batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal alloy-based active material (Si-based or Sn-based alloy) is used to increase energy density, then theoretical capacity is improved, but volume expansion occurs during charge and discharge causing electrode peeling, collapse, and breakage of electrically conductive path
Solution Approach 1:
The patent embeds metal alloy particles (Si, Sn, or their alloys) inside a carbonaceous material core, creating a core-shell structure where the metal particles are nested within the carbon matrix. This nested structure allows the metal particles to expand and contract during charge-discharge cycles while being constrained by the carbon shell, preventing electrode collapse and maintaining electrical conductivity paths.
Solution Approach 2:
The patent creates a composite active material consisting of metal alloy particles combined with carbonaceous material (such as graphite, amorphous carbon, or carbon nanotubes). This composite structure combines the high capacity of metal alloys with the structural stability and conductivity of carbon, resolving the contradiction between capacity and stability.
2Ease of manufacture
If metal particles are mechanically mixed with carbon material, then composite material is formed, but interface adhesion force is relatively low causing particles to be peeled away from surface
Solution Approach 1:
The patent replaces mechanical mixing with a chemical synthesis approach where metal particles are formed in-situ within the carbonaceous material matrix through pyrolysis of a composite resin. This substitution of mechanical process with chemical process creates strong chemical bonds at the metal-carbon interface, eliminating the adhesion problems associated with mechanical mixing.
Solution Approach 2:
The patent uses a composite resin as an intermediary material that contains both metal precursors and carbon precursor in a molecularly mixed state. During pyrolysis, this intermediary resin decomposes to form the final composite structure with strong interfacial bonding, acting as a mediator that ensures intimate contact and strong adhesion between metal and carbon phases.
3Manufacturing precision
If reduction deposition method (plating method or electroless method) is used to deposit metal nano particles from liquid phase to carbon phase, then metal particles are formed, but interface adhesion force is relatively low causing particles to be peeled away
Solution Approach 1:
The patent replaces wet chemical deposition methods (plating or electroless deposition) with a pyrolysis-based solid-state synthesis approach. The composite resin is heated to decompose and form metal particles directly within the carbon matrix, creating strong chemical bonds at the interface without relying on weak physical adhesion from liquid-phase deposition.
4Manufacturing precision
If nano sheet laminate is formed from nano sheet metal and graphenes, then composite structure is created, but operation is complicated and efficiency is low making it unsuitable for industrial mass production
Solution Approach 1:
The patent merges the metal precursor and carbon precursor into a single composite resin molecule structure before pyrolysis. This pre-combined molecular structure ensures intimate mixing and uniform distribution of metal and carbon phases after decomposition, achieving the fine-structure benefits of laminated structures through a simplified one-step pyrolysis process rather than complex multi-step assembly.
Solution Approach 2:
The patent changes the physical and chemical parameters of the starting materials by using a soluble composite resin that can be processed from liquid or paste form. This parameter change allows the material to be applied to electrodes using conventional coating techniques followed by pyrolysis, dramatically simplifying the manufacturing process compared to handling and assembling nano sheets.
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 active material exhibits high capacity and excellent cycle characteristics, simplifying the manufacturing process and improving the stability and performance of negative electrodes in nonaqueous secondary batteries, while maintaining high energy density.
Implementation Method 1
an active material for negative electrodes of nonaqueous secondary batteries obtained by pyrolysis of a composite resin (A)
Data Source
AI summary
An active material having a high capacity for negative electrodes of nonaqueous secondary batteries is provided by pyrolysis of a composite resin (A) which has a silanol group and/or a hydrolysable silyl group and which contains a polysiloxane segment (a1) and a polymer segment (a2) other than the polysiloxane segment (a1), and furthermore, a negative electrode using the above active material and a nonaqueous secondary battery including the above negative electrode are also provided. In addition, by pyrolysis of a dispersion liquid obtained from the composite resin (A), silicon particles, and an organic solvent, an active material having a high capacity for negative electrodes of nonaqueous secondary batteries is provided, and furthermore, a negative electrode using the above active material and a nonaqueous secondary battery including the above negative electrode are also provided.