Polyether Solid Electrolyte Coating for Battery Contact Stability
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Solution Overview
Problem
All-solid-state lithium secondary batteries face issues with charge-discharge characteristics due to gaps between active material particles and solid electrolytes, leading to incomplete contact and strain-induced detachment of the sulfide solid electrolyte layer, resulting in poor charge-discharge efficiency and capacity retention.
Innovation Solution
Coating the surface of electrode active material particles with a polyether-based organic solid electrolyte, which is more flexible and deformable than traditional sulfide or oxide solid electrolytes, to fill gaps and maintain contact, thereby enhancing electrical contact and preventing strain-induced detachment, with an average thickness of 20 nm or less to ensure efficient ion transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sulfide solid electrolyte layer is coated on the surface of electrode active material particles, then the battery structure is formed, but gaps form between particles and electrolyte leading to poor contact and strain-induced detachment
Solution Approach 1:
The patent uses a composite coating structure consisting of an inner sulfide solid electrolyte layer and an outer polyether-based organic solid electrolyte layer. This composite structure combines the advantages of both materials: the sulfide layer provides baseline ionic conductivity while the polyether layer provides flexibility and deformability to maintain intimate contact with electrode particles during volume changes, preventing detachment and ensuring reliable electrical contact throughout battery cycling.
Solution Approach 2:
The patent changes the physical and chemical parameters of the electrolyte coating by introducing a polyether-based organic solid electrolyte with different mechanical properties (higher flexibility and deformability) compared to traditional sulfide solid electrolytes. This parameter change allows the coating to adapt to volume changes of electrode particles during charge-discharge cycles, maintaining continuous contact and improving both contact stability and completeness.
2Reliability
If the solid electrolyte layer is made thicker to ensure coverage, then coverage is improved, but ion transport efficiency decreases
Solution Approach 1:
The patent employs a thin film approach with the polyether-based organic solid electrolyte coating applied at controlled thickness to ensure adequate coverage of electrode particles while maintaining thin enough dimensions for efficient ion transport. The flexible nature of this thin film allows it to conform to particle surfaces and maintain contact during volume changes without requiring excessive thickness, thus balancing coverage and ion transport speed.
3Device complexity
If traditional sulfide solid electrolyte is used, then the battery structure is simple, but charge-discharge characteristics are poor due to detachment
Solution Approach 1:
The patent introduces a composite electrolyte structure with multiple layers (sulfide solid electrolyte inner layer and polyether-based organic solid electrolyte outer layer) to improve charge-discharge characteristics. This composite structure adds complexity but provides superior performance by combining the ionic conductivity of sulfide electrolytes with the flexibility and adhesion properties of polyether electrolytes, preventing detachment and maintaining efficient charge transfer throughout battery operation.
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 polyether-based organic solid electrolyte improves charge-discharge characteristics by increasing the area of contact between active materials and electrolytes, allowing for faster ion transport and enhanced charge and discharge capacities while maintaining contact even after repeated cycles, thus improving battery performance.
Implementation Method 1
the polyether-based organic solid electrolyte is more flexible and deformable than traditional sulfide or oxide solid electrolytes, to fill gaps and maintain contact
Implementation Method 2
The polyether-based organic solid electrolyte is a compound of a polymer having an ether bond and an electrolytic salt
Data Source
AI summary
A battery has a cathode, an anode, and a first solid electrolyte. The cathode contains a particle of a cathode active material, and the anode contains a particle of an anode active material. The first solid electrolyte is disposed between the cathode and the anode. At least one of the surface of the particle of the cathode active material and the surface of the particle of the anode active material is coated with a polyether-based organic solid electrolyte. The polyether-based organic solid electrolyte is in contact with the first solid electrolyte. The polyether-based organic solid electrolyte is a compound of a polymer having an ether bond and an electrolytic salt.