Copper-Alloy Anode Current Collector for Sulfide Solid-State Batteries
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Solution Overview
Problem
In sulfide solid-state batteries, the reaction between the copper anode current collector layer and the sulfide solid electrolyte leads to increased resistance and irreversible reactions, reducing battery capacity, and existing solutions complicate the production process or require additional reaction-inhibiting layers.
Innovation Solution
An anode with a current collector layer made from a copper alloy containing metals of higher ionization tendency than copper, such as zinc, beryllium, or tin, which are work-hardened to achieve high tensile strength and elongation after fracture, suppressing reactions with the sulfide solid electrolyte without the need for additional inhibiting layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reaction-inhibiting layer is added between the anode mixture layer and anode current collector layer to suppress copper-sulfide formation, then battery capacity is improved, but device complexity and manufacturing steps increase
Solution Approach 1:
The patent extracts the harmful copper element from the current collector material by replacing pure copper with copper alloys containing metals of higher ionization tendency (such as zinc, beryllium, or tin). This substitution eliminates the need for separate reaction-inhibiting layers while preventing copper sulfide formation at the interface between the current collector and sulfide solid electrolyte.
Solution Approach 2:
The patent changes the chemical composition parameters of the current collector by specifying copper alloys with controlled ratios of copper (5-99 atom%) and metals of higher ionization tendency (1-95 atom%). This parameter modification inherently provides reaction inhibition without requiring additional structural layers.
2Reliability
If a reaction-inhibiting layer is added to prevent copper sulfide formation, then electrochemical performance is improved, but volumetric energy density decreases
Solution Approach 1:
The patent removes the need for separate reaction-inhibiting layers by integrating the reaction prevention function directly into the current collector material through alloying. This eliminates the additional volume that would be occupied by separate protective layers, thereby maintaining high volumetric energy density while improving electrochemical performance.
3Power
If pure copper is used for the anode current collector layer, then electrical conductivity is improved, but reaction with sulfide solid electrolyte increases leading to higher resistance
Solution Approach 1:
The patent employs composite copper alloy materials that combine copper (providing electrical conductivity) with metals of higher ionization tendency (providing reaction resistance). The alloy composition maintains sufficient electrical conductivity while the added metals form protective surface layers that prevent harmful reactions with the sulfide solid electrolyte, thereby reducing interface resistance.
Solution Approach 2:
The patent converts the potential harm of copper-sulfide formation into a benefit by using metals of higher ionization tendency that preferentially react with sulfur to form stable surface layers. These layers act as protective barriers that prevent further degradation while maintaining good electrical contact, thus converting the harmful reaction tendency into a protective mechanism.
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
This approach reduces electrochemical reactivity with the sulfide solid electrolyte, preventing the formation of copper sulfide and enhancing the charge/discharge performance of the battery while maintaining mechanical integrity, thus improving battery capacity and simplifying production.
Implementation Method 1
at least a surface of the anode current collector layer is made from material that contains an alloy of copper and metal of a higher ionization tendency than copper
Implementation Method 2
the anode current collector layer (10) was obtained by work-hardening, not annealing after work-hardening
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
Copper reacts with a sulfide solid electrolyte to generate copper sulfide when an anode current collector layer made from copper, and an anode mixture layer containing the sulfide solid electrolyte are used to compose an anode, and the resistance of the interface between the anode current collector layer and the anode mixture layer increases. To alloy an anode current collector layer to lower the reactivity to a sulfide solid electrolyte, specifically, an anode includes: an anode mixture layer; and an anode current collector layer that is in contact with the anode mixture layer, wherein the anode mixture layer contains an anode active material and a sulfide solid electrolyte, and at least a surface of the anode current collector layer is made from material that contains an alloy of copper and metal of a higher ionization tendency than copper, the surface being in contact with the anode mixture layer.