Multi-Layer Silicon-Graphite Anode for Adhesion and Quick Charging
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Solution Overview
Problem
Lithium secondary batteries face limitations in thermal stability and quick charging characteristics due to the use of graphite-based anodes, which hinder the achievement of desired performance levels in energy storage applications, particularly in electric vehicles and mobile devices.
Innovation Solution
A multi-layered anode structure is introduced, comprising a first layer of natural graphite and artificial graphite on a current collector, and a second layer containing a silicon-based compound with artificial graphite, optimized in specific weight ratios and binder content to enhance adhesion, thermal stability, and quick charging capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mixture of natural graphite and artificial graphite is used as anode material, then adhesion to current collector and output characteristics are improved, but quick charging performance is lowered
Solution Approach 1:
The anode is divided into two distinct layers: a first anode active material layer containing natural graphite and artificial graphite for adhesion and output characteristics, and a second anode active material layer containing silicon-based compound and artificial graphite for quick charging performance. This segmentation allows each layer to optimize for its specific function without compromising the other.
Solution Approach 2:
Different regions of the anode are assigned different material compositions tailored to their specific functional requirements. The first layer near the current collector uses natural graphite mixture for adhesion, while the second layer uses silicon-based compound for enhanced lithium ion diffusion and quick charging capability.
2Reliability
If artificial graphite alone is used in multi-layered electrode, then stability is improved, but quick charging and stability cannot be improved to desired level
Solution Approach 1:
The second anode active material layer uses a composite of artificial graphite and silicon-based compound. The artificial graphite provides structural stability while the silicon-based compound enhances lithium ion diffusion rate and quick charging performance, achieving both stability and improved quick charging capability simultaneously.
3Reliability
If graphite-based anode is used, then electrochemical reaction potential close to lithium metal and reaction reversibility are achieved, but thermal stability and quick charging characteristics are limited
Solution Approach 1:
The anode is segmented into two layers with different material compositions. The first layer maintains graphite-based properties for electrochemical performance, while the second layer incorporates silicon-based compound to enhance thermal stability and quick charging characteristics without compromising electrochemical reaction potential.
Solution Approach 2:
The invention changes the material composition parameter by introducing silicon-based compound in the second layer. This parameter change improves thermal stability and lithium ion diffusion rate while maintaining the electrochemical reaction potential close to lithium metal through the graphite-based first layer.
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 proposed anode structure significantly improves thermal stability and quick charging characteristics of lithium secondary batteries, ensuring better performance and lifespan by leveraging the adhesion properties of natural graphite and the reactive capabilities of silicon-based compounds.
Implementation Method 1
reaction reversibility with lithium ions should be high
Implementation Method 2
Considering excellent adhesion of natural graphite
Implementation Method 3
a diffusion rate of lithium ions in the active material should be fast
Data Source
AI summary
The present disclosure relates to an anode for a lithium secondary battery and a lithium secondary battery including the same, wherein the anode includes an anode current collector; a first anode active material layer formed on at least one surface of the anode current collector and containing a mixture of natural graphite and artificial graphite in a weight ratio of 13˜34:66˜87 and a first binder as the anode active material; and a second anode active material layer formed on the first anode active material layer and containing a mixture of artificial graphite and a silicon-based compound in a weight ratio of 91˜99:1˜9 and a second binder as the anode active material.