Double-Layer Lithium Battery Anode for Uniform Pre-Lithiation
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Solution Overview
Problem
Existing lithium secondary batteries using silicon-based active materials face issues with electrode surface degradation, non-uniform pre-lithiation, and reduced service life due to volume expansion during charging and discharging cycles.
Innovation Solution
A double-layer negative electrode structure comprising a first layer of SiOx and a second layer of carbon-based or silicon-based active materials, along with conductive and binder components, to enhance uniformity and prevent surface degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a silicon-based compound is used as a negative electrode active material to increase capacity, then the discharge capacity is improved, but the volume rapidly expands during charging resulting in conductive path disconnection and capacity deterioration
Solution Approach 1:
The patent applies the nesting principle by placing the silicon-based active material particles inside a porous carbon matrix. The carbon matrix acts as a container that accommodates the silicon particles and their volume expansion during charging, while maintaining the overall structural integrity and conductive pathways. This nested structure prevents conductive path disconnection while preserving the high capacity benefits of silicon-based materials.
Solution Approach 2:
The patent employs a porous carbon matrix that functions as a flexible shell surrounding the silicon-based active material. This carbon shell can deform to accommodate the volume changes of silicon during lithiation and delithiation cycles, while maintaining continuous electrical contact. The flexibility of the carbon shell prevents structural failure and conductive path disconnection despite the rapid volume expansion of silicon.
2Quantity of substance
If the proportion of silicon-based active material is increased to achieve high-density energy battery, then the energy density is improved, but pre-lithiation becomes concentrated on the surface resulting in surface degradation and reduced service life
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of lithium ions within the electrode structure. The porous carbon matrix provides preferential pathways for lithium ion diffusion, ensuring uniform pre-lithiation throughout the bulk of the electrode rather than concentration at the surface. This localized control of lithium distribution prevents surface degradation while maintaining high energy density through increased silicon content.
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 double-layer structure improves cycle performance and capacity characteristics by preventing electrode surface degradation and ensuring uniform pre-lithiation, maintaining high capacity and density while extending the battery's service life.
Implementation Method 1
a first negative electrode active material layer including a first negative electrode active material layer composition including a first negative electrode active material, the second negative electrode active material layer includes a second negative electrode active material layer composition including a second negative electrode active material
Implementation Method 2
a negative electrode for a lithium secondary battery, a manufacturing method of anode for lithium secondary battery, and a lithium secondary battery including anode
Data Source
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AI summary
The present application relates to a negative electrode for a lithium secondary battery, a method for preparing a negative electrode for a lithium secondary battery, and a lithium secondary battery including the negative electrode.