Graphite Anode Composition for High-Capacity Battery Life Stability
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Solution Overview
Problem
Existing anode active materials for lithium secondary batteries face challenges in achieving a balance between high capacity and stability, particularly in terms of thermal and mechanical stability, which can lead to deteriorated life-span properties and operational reliability.
Innovation Solution
The use of a blend of natural and artificial graphite-based anode active materials, each with specific crystallite sizes and XRD orientation ratios, to enhance capacity and life-span properties, where natural graphite provides high capacity and artificial graphite enhances stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the anode active material is designed to have high power/capacity composition, then capacity and power are improved, but thermal and mechanical stability are lowered
Solution Approach 1:
The patent uses a composite anode active material consisting of natural graphite particles and artificial graphite particles. The natural graphite provides high capacity through its layered structure that facilitates lithium insertion/extraction, while the artificial graphite component enhances thermal and mechanical stability. This composite approach allows the material to achieve both high capacity and improved stability simultaneously, resolving the contradiction between capacity enhancement and stability maintenance.
2Quantity of substance
If the anode active material is designed to have high power/capacity composition, then capacity and power are improved, but life-span property and operational reliability are deteriorated
Solution Approach 1:
The composite structure of natural and artificial graphite particles creates a synergistic effect where the artificial graphite provides structural robustness and cycle stability, while the natural graphite ensures high capacity. This combination maintains operational reliability and extends battery life-span while preserving high capacity performance.
3Quantity of substance
If natural graphite is used to provide high capacity, then capacity is improved, but stability at high temperatures is lowered
Solution Approach 1:
The patent applies local quality by having different graphite components serve different functions within the same anode material system. The artificial graphite particles specifically address high-temperature stability requirements, while the natural graphite particles focus on providing high capacity. This functional differentiation allows the overall material to achieve both high capacity and high-temperature stability without compromising either property.
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 combination of natural and artificial graphite-based materials maintains high capacity while improving life-span stability, especially at high temperatures, through optimized crystallite sizes and orientation ratios.
Implementation Method 1
An XRD orientation ratio of the first anode active material is in a range from 0.9 to 1.2, and an XRD orientation ratio of the second anode active material is in a range from 1 to 5. The XRD orientation ratio is defined as I(004)/I(110) which is a ratio of a peak intensity at a (004) plane relative to a peak intensity at a (110) plane.
Data Source
AI summary
An anode active material for a lithium secondary battery according to an embodiment of the present invention includes a first anode active material and a second anode active material, each of which includes a carbon-based active material and has a crystallite size in a range from 50 nm to 60 nm. An XRD orientation ratio of the first anode active material is in a range from 0.9 to 1.2, and an XRD orientation ratio of the second anode active material is in a range from 1 to 5. High-temperature storage and life-span properties are improved while maintaining high capacity using the combination of the first and second anode active materials.