Anode Current Collector Sulfidation Protection in Solid-State Batteries
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Solution Overview
Problem
Conventional all-solid-state secondary batteries face issues with anode current collector corrosion and copper foil fracture due to the use of sulfide solid electrolytes, which limits their specific capacity and increases costs, and also suffer from high contact interface resistance and cycle deterioration of anode materials like silicon.
Innovation Solution
The battery design incorporates a sulfidation-resistant layer, such as a copper sulfide or copper oxide layer, on the anode current collector, and a sulfidation-resistant metal layer on the anode current collector, along with a sulfide solid electrolyte containing monovalent or divalent metals and sulfur, to prevent corrosion and enhance mechanical strength, allowing for the use of copper or copper alloys as current collectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide solid electrolyte is used to achieve high ion conductivity and safety, then safety and reliability are improved, but anode current collector corrosion occurs
Solution Approach 1:
A protective coating layer (such as aluminum oxide, aluminum hydroxide, or other barrier layers) is applied to the anode current collector surface to act as an intermediary barrier between the copper-based current collector and the sulfide solid electrolyte, preventing direct contact and corrosion while maintaining electrical conductivity
Solution Approach 2:
The anode current collector is designed as a composite structure combining copper (for high conductivity) with corrosion-resistant materials or protective coatings (such as aluminum-based protective layers), creating a multi-layer composite that provides both electrical performance and chemical stability against sulfide electrolytes
2Ease of manufacture
If conventional copper foil is used as anode current collector to reduce cost, then cost is reduced, but press resistance is insufficient leading to deformation and rupture
Solution Approach 1:
The current collector is constructed as a composite structure with a copper base layer (for conductivity and cost-effectiveness) combined with a protective outer layer (such as aluminum alloy or other high-strength materials) that provides the necessary press resistance and mechanical strength to prevent deformation and rupture during battery assembly and operation
Solution Approach 2:
Different regions of the current collector are assigned different properties: the bulk material maintains copper's high conductivity and low cost, while the surface or specific structural regions incorporate high-strength materials or undergo surface treatment to provide localized press resistance where mechanical strength is most needed
3Quantity of substance
If lithium cobaltate is used as cathode active material to achieve high capacity, then specific energy is improved, but high contact interface resistance barrier with solid electrolytes occurs
Solution Approach 1:
An intermediate buffer layer (such as lithium phosphate, lithium oxide, or other lithium-containing compounds) is applied to the surface of the lithium cobaltate cathode to serve as a mediator between the cathode active material and the sulfide solid electrolyte, reducing interfacial resistance while maintaining the high capacity properties of lithium cobaltate
Solution Approach 2:
The surface properties of the lithium cobaltate cathode are modified through surface treatment, coating, or chemical modification to change the interfacial parameters (such as surface energy, conductivity, or chemical composition) and reduce contact resistance with the solid electrolyte while preserving the bulk material's high capacity characteristics
4Stability of the object's composition
If graphite is used as anode active material to achieve stability, then stability is improved, but low specific capacity occurs
Solution Approach 1:
The anode is designed as a hybrid structure that merges graphite (providing structural stability and good cyclability) with high-capacity materials such as silicon, tin, or other alloying materials, combining the advantages of both material types to achieve both stability and high specific capacity in the same anode structure
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 configuration enhances the safety, stability, and reliability of the battery by preventing corrosion and mechanical failure, enabling high-speed charge-discharge capabilities and extended cycle life while maintaining high specific energy capacity.
Implementation Method 1
a solid electrolyte layer comprising a sulfide solid electrolyte that contains a monovalent or divalent metal and sulfur
Implementation Method 2
a sulfidation resistant layer which is a copper sulfide layer that contains copper sulfide or a copper oxide layer that contains copper oxide
Data Source
AI summary
An all-solid-state secondary battery, wherein: an anode current collector that contains copper or copper alloy; a cathode current collector comprising aluminum, aluminum alloy or stainless steel, provided opposite to the anode current collector; an anode active material layer formed there between from the anode current collector side on the surface of the anode current collector; a solid electrolyte layer comprising a sulfide solid electrolyte that contains a monovalent or divalent metal and sulfur; and a cathode active material layer formed on the surface of the cathode current collector are layered successively, is used. A sulfidation resistant layer is formed on the surface of the anode current collector on which the anode active material layer is formed. Or, the surface of the anode current collector on which the anode active material layer is formed has a compressive strength of 1250 to 3000 MPa.