Self-Supported Electrodes Using Carbonized Polymer for Silicon Batteries
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Solution Overview
Problem
Conventional lithium-ion battery electrodes face challenges with silicon expansion, leading to mechanical failure and loss of electrical contact due to the inability to accommodate the significant volume changes during lithiation and de-lithiation, which results in reduced cycle life and capacity.
Innovation Solution
The development of self-supported electrodes using a carbonized polymer that includes silicon and carbon composite materials, where the carbonized polymer acts as both a conductive matrix and an expansion buffer, eliminating the need for a metal foil current collector and enhancing mechanical durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrodes with metal foil current collectors are used, then mechanical support is provided, but silicon expansion causes mechanical failure and loss of electrical contact
Solution Approach 1:
The invention removes the metal foil current collector from the electrode structure, extracting the problematic component that causes mechanical failure during silicon expansion. The self-supported film structure eliminates the interface between metal foil and silicon particles where mechanical failure and loss of electrical contact occur.
Solution Approach 2:
The invention uses a composite structure consisting of a carbonized polymer matrix embedded with silicon particles. This composite material provides both mechanical support and electrical conductivity inherently, eliminating the need for separate metal foil current collectors and binder materials while accommodating silicon expansion.
2Quantity of substance
If silicon particles are added to increase capacity, then energy density improves, but volume expansion during lithiation causes mechanical failure
Solution Approach 1:
The invention changes the physical and chemical parameters of the electrode structure by using a carbonized polymer matrix with specific mechanical properties that can accommodate the volume expansion of silicon particles during lithiation. The matrix structure and composition are optimized to maintain structural integrity while allowing silicon expansion.
Solution Approach 2:
The invention creates a composite material where silicon particles are embedded in a carbonized polymer matrix. This composite structure combines the high capacity of silicon with the mechanical durability and flexibility of the carbonized polymer, enabling both high energy density and long cycle life.
3Use of energy by moving object
If metal foil current collectors are used, then electrical conductivity is provided, but they add weight and complexity to the electrode structure
Solution Approach 1:
The carbonized polymer matrix performs multiple functions simultaneously: it provides mechanical support, electrical conductivity, and structural framework for the electrode. This multi-functional material eliminates the need for separate metal foil current collectors and binder materials, simplifying the overall electrode structure.
Solution Approach 2:
The invention merges the functions of the current collector, binder, and active material holder into a single carbonized polymer matrix structure. This consolidation eliminates multiple components and interfaces, reducing structural complexity while maintaining or improving electrical conductivity.
4Ease of manufacture
If conventional electrode structures are used, then manufacturing is simplified, but significant irreversible capacity is lost due to mechanical failure
Solution Approach 1:
The carbonized polymer matrix is self-supported and inherently provides both mechanical strength and electrical conductivity without requiring additional metal foils or binder materials. This self-sufficient structure eliminates the complex assembly processes needed for conventional electrodes while reducing irreversible capacity loss through improved mechanical stability.
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 solution allows for higher energy density, improved cycle life, and reduced irreversible capacity by maintaining electrical contact during silicon expansion, while also simplifying manufacturing and reducing costs.
Implementation Method 1
the carbonized polymer acts as both a conductive matrix and an expansion buffer, eliminating the need for a metal foil current collector
Implementation Method 2
the carbonized polymer acts as both a conductive matrix and an expansion buffer
Data Source
AI summary
Electrodes and methods of forming electrodes are described herein. The electrode can be an electrode of an electrochemical cell or battery. The electrode includes a current collector and a film in electrical communication with the current collector. The film may include a carbon phase that holds the film together. The electrode further includes an electrode attachment substance that adheres the film to the current collector.