Multi-Layer Carbon Anode Orientation for Fast Lithium-Ion Transfer
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Solution Overview
Problem
Existing lithium secondary batteries face challenges in achieving high power performance due to issues with electrolyte impregnation, lithium ion transfer efficiency, and internal resistance, particularly in anode structures.
Innovation Solution
The anode for lithium secondary batteries features a multi-layer structure with at least one oriented layer having a Degree of Divergence (DD) value of 19 or more, optimized through XRD measurements, enhancing electrolyte impregnation and lithium ion transfer, and incorporating a carbon-based anode active material with specific peak intensity ratios and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer anode structure is used, then the structure is simple and easy to manufacture, but the electrolyte impregnation is poor and lithium ion transfer efficiency is low
Solution Approach 1:
The anode active material layer is divided into multiple sub-layers (first anode active material layer, second anode active material layer, third anode active material layer) with different orientations and properties. Each layer serves a specific function: the first layer provides good adhesion to the current collector, the second layer enhances electrolyte impregnation with high orientation, and the third layer contributes to capacity. This segmentation resolves the contradiction by improving electrolyte impregnation and lithium ion transfer through specialized layers while maintaining manufacturing feasibility through a systematic multi-layer approach.
Solution Approach 2:
Different regions of the anode active material layer are given different local properties through varying orientations. The first layer has low orientation (DD value < 19) for good adhesion, the second layer has high orientation (DD value ≥ 19) for excellent electrolyte impregnation, and the third layer has moderate orientation. This local quality differentiation allows each region to optimize for its specific function, resolving the contradiction between structure complexity and performance by creating a functionally optimized multi-layer structure.
2Reliability
If the anode active material layer has high orientation (DD value ≥ 19), then the electrolyte impregnation is improved, but the adhesion to current collector may be reduced
Solution Approach 1:
The anode active material layer is segmented into multiple layers with different orientation characteristics. The first layer adjacent to the current collector has low orientation (DD value < 19) to ensure strong adhesion, while the second layer has high orientation (DD value ≥ 19) to maximize electrolyte impregnation. This segmentation allows the adhesion function and impregnation function to be separated into different layers, resolving the contradiction between adhesion strength and electrolyte impregnation.
Solution Approach 2:
Different local regions of the anode active material layer are assigned different orientation qualities suited to their specific functions. The region adjacent to the current collector (first layer) has low orientation for optimal adhesion, while the upper region (second layer) has high orientation for optimal electrolyte impregnation. This local quality differentiation resolves the contradiction by allowing each region to optimize for its primary function without compromising the other.
3Reliability
If a multi-layer structure with oriented layers is implemented, then the high-rate capability and cycle-life characteristics are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The anode active material layer is segmented into three distinct layers with progressively increasing orientation, where the second layer serves as a high-orientation core layer (DD value ≥ 19) that provides the critical electrolyte impregnation function. This segmentation allows the manufacturing process to focus precision control on the critical second layer while the first and third layers can have more relaxed orientation requirements, thus improving high-rate capability and cycle-life characteristics while managing manufacturing precision requirements through differentiated layer specifications.
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 optimized anode structure improves high-rate capability, cycle-life characteristics, and reduces internal resistance, making it suitable for high-power applications.
Implementation Method 1
various carbon-based materials capable of intercalating/deintercalating lithium ions such as artificial graphite, natural graphite, hard carbon, and the like have been used
Implementation Method 2
DD (Degree of Divergence) value defined by Equation 1 of 19 or more. (In Equation 1, I a is a sum of peak intensities at non-planar angles measured by XRD using a CuKα ray, and I total is a sum of peak intensities at all angles measured by XRD using a CuKα ray.)
Data Source
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AI summary
The present invention relates an anode for a lithium secondary battery and a lithium secondary battery comprising same. The anode for a lithium secondary battery comprises a current collector; and an anode active material layer formed on the current collector and including a carbon-based anode active material, wherein the anode active material layer has a multi-layer structure of three or more layers and at least one layer of the anode active material layer is an oriented layer having a degree of divergence (DD) of 19 or greater, thee DD being defined by the following formula 1: DegreeofDivergenceDD=Ia/Itotal*100 Ia is a sum of peak intensities at non-planar angles measured by XRD using a CuKα ray, and, Itotal is a sum of peak intensities at all angles measured by XRD using a CuKα ray.).