Electrolytic Copper Foil Texture Control for Electrolyte Corrosion
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Solution Overview
Problem
Copper foils used in lithium-ion cells are prone to corrosion from electrolyte solutions, leading to reduced cycle life and safety concerns, as existing corrosion resistance treatments either fail to provide long-term protection or are unsuitable for high-temperature applications.
Innovation Solution
The development of an electrolytic copper foil with specific surface characteristics, including controlled intensity ratios and full width at half maximum values of characteristic peaks, and a yield strength greater than 230 MPa, which enhances corrosion resistance and suitability for lithium-ion cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If corrosion resistance treatment is applied to copper foil, then corrosion resistance is improved, but bonding strength or application flexibility deteriorates
Solution Approach 1:
The patent changes the crystallographic parameters of the copper foil surface by controlling the electrolytic deposition process to achieve a specific orientation distribution ((111)+(200))/( (111)+(200)+(220) ) ≥ 0.83. This parameter change in crystal orientation inherently provides corrosion resistance without requiring additional cover layers or corrosion inhibitors, thus maintaining good bonding strength and manufacturing flexibility.
2Reliability
If cover layer is coated on copper foil, then corrosion resistance is improved, but device complexity increases
Solution Approach 1:
The patent extracts the corrosion resistance function from the copper foil's crystal structure itself rather than adding a separate cover layer. By controlling the electrolytic deposition to create specific crystal orientations, the copper foil inherently resists corrosion from electrolyte solutions, eliminating the need for additional protective layers and reducing structural complexity.
3Reliability
If corrosion inhibitor is used, then corrosion resistance is improved, but temperature application range is limited
Solution Approach 1:
The patent makes the copper foil self-protecting through controlled crystal orientation. The electrolytically deposited copper foil with specific orientation distribution naturally resists corrosion from electrolyte solutions without requiring external corrosion inhibitors. This self-service mechanism allows the copper foil to maintain corrosion resistance across a wide temperature range, including high-temperature applications.
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 improved copper foil effectively resists corrosion from electrolyte solutions, extending the cycle life and safety of lithium-ion cells, while maintaining high capacity and coating quality, making it suitable for both positive and negative electrodes.
Implementation Method 1
an electrolytic copper foil comprising a first surface and a second surface opposite the first surface
Implementation Method 2
The first surface and the second surface are analyzed by grazing incidence X-ray diffraction (GIXRD)
Data Source
Figure 1
Figure 2
AI summary
Provided are an electrolytic copper foil (60), an electrode and a lithium-ion cell. The electrolytic copper foil (60) has a first surface (621) and a second surface (631), which are analyzed by GIXRD, and each have an intensity of a characteristic peak of (111) plane denoted by I1, an intensity of a characteristic peak of (200) plane denoted by I2, an intensity of a characteristic peak of (220) plane denoted by I3, an FWHM of the characteristic peak of (111) plane denoted by W1, and an FWHM of the characteristic peak of (200) plane denoted by W2. The first and second surfaces (621, 631) each have a ratio of (I1+I2)/(I1+I2+I3) not less than 0.83 and a value of (W1+W2) not more than to 0.80. By controlling the features, it can improve the corrosion resistance of the electrolytic copper foil and increase the safety of the lithium-ion cell.