Graphite Oxide Anode Coating for Volume-Stable Li-Ion Batteries
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Solution Overview
Problem
The existing graphite-based negative electrode materials in lithium secondary batteries face challenges such as volume expansion and shrinkage during charging and discharging, leading to reduced battery performance and non-uniform electrode manufacturing.
Innovation Solution
A graphite-based negative electrode material is developed, comprising graphite oxide obtained by oxidizing the surface of first graphite, and a graphite coating with second graphite and low crystalline carbon. The graphite coating is applied in a ratio of 1/9 to 1/3 to the graphite oxide, resulting in a material with specific properties that enhance battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If natural graphite is used as negative electrode material, then cost is reduced and electrochemical properties are maintained, but volume expansion and shrinkage occur during charge/discharge leading to reduced battery performance
Solution Approach 1:
The patent applies composite materials by combining natural graphite particles with artificial graphite coating. The natural graphite core maintains cost-effectiveness and electrochemical properties, while the artificial graphite shell provides structural stability and suppresses volume expansion/shrinkage during charge/discharge cycles. This composite structure resolves the contradiction between maintaining reliability and improving volume stability.
Solution Approach 2:
The patent changes the physical and chemical parameters of the graphite material by applying a coating layer with controlled thickness (1-10 μm) and specific composition (artificial graphite). This parameter modification allows the material to maintain its electrochemical activity while reducing volume instability, thereby improving battery performance without sacrificing cost-effectiveness.
2Ease of manufacture
If natural graphite is used as negative electrode material, then cost is reduced, but edge parts are exposed causing electrolyte penetration and decomposition reactions leading to delamination and broken edges
Solution Approach 1:
The composite structure of natural graphite core with artificial graphite coating protects the exposed edge parts of natural graphite particles. The coating layer acts as a protective barrier that prevents electrolyte penetration and decomposition reactions at the edges, thereby maintaining edge integrity and preventing delamination while keeping the cost-effective natural graphite core.
Solution Approach 2:
The artificial graphite coating serves as an intermediary layer between the natural graphite particles and the electrolyte. This intermediate layer prevents direct contact between the electrolyte and the vulnerable edge parts of natural graphite, thereby preventing harmful chemical reactions while maintaining the overall structure and reducing manufacturing defects.
3Power
If graphite is used as negative electrode material, then high discharge voltage of 3.6 V is achieved, but theoretical capacity is limited to about 372 mAh/g
Solution Approach 1:
The patent applies multi-functionality by designing a composite graphite material that simultaneously maintains the high discharge voltage characteristic of graphite (3.6 V) while increasing the theoretical capacity. The artificial graphite coating provides additional lithium insertion sites, enabling the material to function both as a voltage-stable electrode and as a high-capacity storage medium, thereby overcoming the capacity limitation of pure natural graphite.
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 solution effectively suppresses volume expansion and shrinkage during battery operation, prevents non-uniformity in electrode manufacturing, and thereby maintains battery performance, achieving improved initial capacity, efficiency, and life characteristics.
Implementation Method 1
a graphite oxide obtained by oxidizing a surface of first graphite
Implementation Method 2
a graphite coating including second graphite and low crystalline carbon positioned on a surface of the second graphite, wherein the graphite coating to the graphite oxide is 1/9 to 1/3
Implementation Method 3
the low crystalline carbon positioned on a surface of the second graphite
Data Source
AI summary
The present exemplary embodiments relate to a graphite-based negative electrode material, a method of manufacturing the same, a negative electrode including the same, and a lithium secondary battery including the same. The graphite-based negative electrode material according to an exemplary embodiment includes: a graphite oxide obtained by oxidizing a surface of first graphite, and a graphite coating including second graphite and low crystalline carbon positioned on a surface of the second graphite, wherein the graphite coating to the graphite oxide is 1/9 to 1/3.