Battery Electrode Coating Structure for Thick High-Capacity Layers
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Solution Overview
Problem
Conventional lithium-ion secondary battery electrodes face issues with increased resistance and adhesion problems due to the softness of sulfur-based active materials, leading to reduced charge and discharge capacity, especially when the electrodes are made thicker.
Innovation Solution
The electrode design includes a conductive coating layer with an average thickness of 0.5 µm or more and an interface tortuosity of 1.05 or more between the conductive coating layer and a composite material layer, which contains an active material with an average particle size of 2 µm or more, enhancing contact and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode is made thicker to increase battery capacity, then the charge and discharge capacity increases, but the adhesion of the composite material layer deteriorates and resistance increases
Solution Approach 1:
A conductive coating layer is formed on the current collector before forming the composite material layer. This preliminary coating layer with controlled thickness (0.5 μm or more) and interface tortuosity (1.05 or more) creates a foundation that prevents adhesion deterioration even when the electrode is made thicker for high capacity applications.
Solution Approach 2:
The conductive coating layer acts as an intermediary between the current collector and the composite material layer. This intermediate layer improves the interfacial contact and adhesion, allowing the composite material layer to maintain strong bonding even when the electrode thickness is increased for higher battery capacity.
2Quantity of substance
If the electrode is made thicker to increase battery capacity, then the charge and discharge capacity increases, but the resistance of the electrode increases
Solution Approach 1:
A conductive coating layer is formed on the current collector before forming the composite material layer. This preliminary coating layer with controlled thickness (0.5 μm or more) and interface tortuosity (1.05 or more) creates a foundation that prevents adhesion deterioration even when the electrode is made thicker for high capacity applications.
Solution Approach 2:
The conductive coating layer acts as an intermediary between the current collector and the composite material layer. This intermediate layer improves the interfacial contact and adhesion, allowing the composite material layer to maintain strong bonding even when the electrode thickness is increased for higher battery capacity.
3Quantity of substance
If sulfur-based active material is used to increase battery capacity, then the charge and discharge capacity increases, but the adhesion to current collector deteriorates due to softness
Solution Approach 1:
The conductive coating layer acts as an intermediary between the current collector and the composite material layer. This intermediate layer improves the interfacial contact and adhesion, allowing the composite material layer to maintain strong bonding even when the electrode thickness is increased for higher battery capacity.
Solution Approach 2:
The interface tortuosity is controlled to be 1.05 or more, which changes the geometric parameters of the interface between the conductive coating layer and the composite material layer. This parameter change increases the contact area and mechanical interlocking, thereby improving adhesion despite the softness of the sulfur-based active material.
Data Source
Figure 1
AI summary
Provided is an electrode comprising a current collector, a conductive coating layer formed on the current collector, and a composite material layer formed on the conductive coating layer, wherein an average thickness of the conductive coating layer is 0.5 µm or more, wherein an interface tortuosity τ between the conductive coating layer and the composite material layer is 1.05 or more, wherein the composite material layer comprises an active material, and wherein the active material has an average particle size d50 of 2 µm or more. It is an object of the present invention to improve the charge and discharge capacity even with a high basis weight.