Secondary Battery Electrode with Perfluoropolyether for Low-Pressure Sulfide Solid State Cells
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Solution Overview
Problem
The production of secondary batteries with sulfide solid electrolytes faces challenges in reducing electrode resistance when using low-pressure pressing methods, which is necessary for simplifying the production process and reducing costs.
Innovation Solution
Incorporating a perfluoropolyether (PFPE) represented by a specific formula into the first electrode of a secondary battery, which contains a sulfide solid electrolyte, to enhance the lubricity and reduce the reactivity with the sulfide solid electrolyte, thereby allowing for effective resistance reduction even at low pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high pressure pressing (200 MPa or more) is applied to electrodes containing sulfide solid electrolyte, then resistance is reduced, but production process complexity and cost increase
Solution Approach 1:
A fluorinated compound with specific chemical structure acts as an intermediary substance between the sulfide solid electrolyte and electrode materials. This intermediary layer reduces chemical reactivity and improves interfacial contact, enabling effective resistance reduction without requiring high pressing pressure. The fluorinated compound mediates the interaction between electrode and electrolyte, achieving low resistance at low pressure conditions.
Solution Approach 2:
The invention changes the chemical composition parameters of the electrode by incorporating fluorinated compounds with specific molecular structures (containing CF3, CF2, or CF groups). This parameter change in chemical composition modifies the interfacial properties between electrode and sulfide solid electrolyte, enabling effective contact and low resistance without high mechanical pressure.
2Ease of manufacture
If low pressure pressing is used to simplify production process, then production cost and process complexity are reduced, but electrode resistance increases
Solution Approach 1:
The fluorinated compound serves as a mediator that enables effective interfacial contact between electrode and sulfide solid electrolyte without requiring high pressing pressure. The specific chemical structure of the fluorinated compound (containing CF3, CF2, or CF groups) provides optimal balance between chemical stability and interfacial adhesion, achieving low resistance at low pressure conditions.
Solution Approach 2:
The electrode is designed as a composite material system combining conventional electrode materials with fluorinated compounds. This composite structure leverages the unique properties of fluorinated compounds (chemical stability, low reactivity with sulfide electrolyte, and good interfacial contact) to achieve low resistance without high pressure pressing.
Data Source
Figure 1
AI summary
Disclosed is a technology for reducing the resistance of a secondary battery including a sulfide solid electrolyte. The secondary battery of the present disclosure includes a first electrode, an electrolyte layer, and a second electrode, wherein at least one of the first electrode and the electrolyte layer contains a sulfide solid electrolyte, and the first electrode contains a perfluoropolyether represented: E1-Rf1-RF-O-Rf2-E2 (1) where Rf1 and Rf2 are each independently a C1-16 divalent alkylene group which may be substituted with one or more fluorine atoms, E1 and E2 are each independently a monovalent group selected from the group consisting of a fluorine group, a hydrogen group, a hydroxyl group, an aldehyde group, a carboxylic acid group, a C1-10 alkyl ester group, an amide group which may have one or more substituents, and an amino group which may have one or more substituents, and RF is a divalent fluoropolyether group.