Antioxidant Copper Foil Coating for High-Temperature Battery Cathodes
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Solution Overview
Problem
Conventional copper foils with antioxidant layers containing chromic acid and glucose have limited heat resistance, restricting their applications, especially at higher temperatures.
Innovation Solution
A surface treatment method for copper foils involving immersion in an antioxidant solution containing a chromic acid compound, an aminotetrazole compound, and a nitrogen-containing heterocyclic compound, forming an antioxidant layer with specific chromium and nitrogen content, and enhanced thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chromic acid and glucose are used as components of the antioxidant layer, then the copper foil is prevented from being easily oxidized at room temperature, but the surface color difference ΔE becomes greater than 8 at higher temperatures (e.g., 250°C)
Solution Approach 1:
The patent changes the chemical composition parameters of the antioxidant layer by replacing glucose with specific nitrogen-containing heterocyclic compounds (benzotriazole, 5-nitrobenzotriazole, or 1-phenylbenzotriazole) and adjusting chromic acid concentration (0.1-5 g/L), thereby improving heat resistance while maintaining antioxidant performance at elevated temperatures up to 250°C
Solution Approach 2:
The patent creates a composite antioxidant layer combining chromic acid compounds with nitrogen-containing heterocyclic compounds, forming a synergistic protective coating that provides both antioxidant properties and enhanced thermal stability, achieving surface color difference ΔE ≤ 8 at 250°C
2Reliability
If metal elements (nickel and zinc) are used in the antioxidant layer, then the copper foil surface is protected from oxidation, but the performance and stability of lithium batteries are reduced
Solution Approach 1:
The patent extracts harmful metal elements (nickel and zinc) from the antioxidant layer composition and replaces them with chromic acid and nitrogen-containing heterocyclic compounds, eliminating the negative impact on lithium battery performance while maintaining effective oxidation protection
Solution Approach 2:
The patent uses organic nitrogen-containing heterocyclic compounds as alternatives to metal plating layers, creating an antioxidant coating that is compatible with lithium battery applications and does not interfere with battery chemistry or performance
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 treated copper foils demonstrate improved heat resistance, maintaining a surface color difference ΔE of less than 8 after baking at 250°C for 10 minutes, making them more suitable for lithium battery applications.
Implementation Method 1
immersing the copper foil substrate in an antioxidant solution containing a chromic acid compound, an aminotetrazole compound, and a nitrogen-containing heterocyclic compound; subjecting the copper foil substrate to be soaked or electroplated in the antioxidant solution for a predetermined time to form an antioxidant layer on a surface of the copper foil substrate
Data Source
AI summary
A surface treatment method of a copper foil, an antioxidant copper foil, and a cathode of a lithium battery are provided. The antioxidant copper foil includes a copper foil substrate and an antioxidant layer formed thereon. The antioxidant layer contains chromium elements derived from a chromic acid compound, and contains nitrogen elements at least partially derived from an aminotetrazole compound and a nitrogen-containing heterocyclic compound. The antioxidant copper foil satisfies the following characteristics: (a) the antioxidant layer has a chromium content of between 5 and 35 μg/m2 determined by XRF; (b) the antioxidant layer has a nitrogen content of between 0.1 and 10 wt % determined by XPS; (c) the antioxidant copper foil has a C—N signal detected by headspace GC-MS; and (d) after baking the antioxidant copper foil at 250° C. for 10 minutes, a surface color difference ΔE of the antioxidant layer is not greater than 8.