Solid-State Battery Electrolyte Interface Design
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Solution Overview
Problem
Existing solid-state lithium ion batteries face challenges with low ion conductivity and stability due to the reactivity of sulfide and complex hydride solid electrolytes with electrode materials, leading to increased battery resistance and reduced performance over charge/discharge cycles.
Innovation Solution
A solid-state battery configuration featuring a lithium-ion-conducting solid electrolyte layer between a sulfide-based positive-electrode layer and a complex hydride-based negative-electrode layer, where the sulfide and complex hydride solid electrolytes are in contact, enhancing ion conductivity and stability by preventing direct contact between reactive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide solid electrolyte is used to achieve high lithium ion conductivity, then ion conductivity is improved, but reactivity with positive-electrode active material increases causing reduction and stability deterioration
Solution Approach 1:
The patent introduces a complex hydride solid electrolyte as an intermediary layer between the sulfide solid electrolyte and the positive-electrode active material. This intermediary prevents direct contact and reaction between the sulfide electrolyte and the positive electrode, thereby maintaining high lithium ion conductivity while preventing reduction of the positive-electrode active material and improving overall stability.
2Stability of the object's composition
If oxide or phosphate compound solid electrolyte is used to ensure stability, then stability is improved, but lithium ion conductivity decreases
Solution Approach 1:
The patent employs a composite solid electrolyte structure combining sulfide solid electrolyte and complex hydride solid electrolyte. The sulfide component provides high lithium ion conductivity, while the complex hydride component provides stability and prevents unwanted reactions. This composite approach achieves both high conductivity and stability that neither material can achieve alone.
3Reliability
If sulfide solid electrolyte contacts positive-electrode active material directly, then ion conductivity is maintained, but interfacial resistance increases due to reaction products
Solution Approach 1:
The complex hydride solid electrolyte serves as a protective intermediary layer that prevents direct interaction between the sulfide solid electrolyte and the positive-electrode active material. This eliminates the formation of reaction products at the interface, thereby maintaining low interfacial resistance while preserving the high lithium ion conductivity of the sulfide electrolyte.
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 configuration achieves high ion conductivity and excellent stability, preventing the reduction of positive-electrode active materials and maintaining discharge capacity over repeated charge/discharge cycles, ensuring long-term battery performance.
Implementation Method 1
a lithium-ion-conducting solid electrolyte layer disposed between the positive-electrode layer and the negative-electrode layer
Implementation Method 2
either or both of the positive-electrode layer and the solid electrolyte layer contain a sulfide solid electrolyte, either or both of the negative-electrode layer and the solid electrolyte layer contain a complex hydride solid electrolyte, and at least part of the sulfide solid electrolyte is in contact with at least part of the complex hydride solid electrolyte
Data Source
Figure 1~3
Figure 4
AI summary
One embodiment provides a solid-state battery that has a positive-electrode layer, a negative-electrode layer, and a lithium-ion-conducting solid electrolyte layer disposed between the positive-electrode layer and the negative-electrode layer. The positive-electrode layer and/or the solid electrolyte layer contains a sulfide solid electrolyte, the negative-electrode layer and/or the solid electrolyte layer contains a solid electrolyte comprising a hydride of a complex, and at least part of the sulfide solid electrolyte is in contact with at least part of the solid electrolyte comprising a hydride of a complex.