Solid Electrolyte Oxygen Gradient for Battery Yield
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Solution Overview
Problem
Nonaqueous electrolyte batteries with sulfide-based solid electrolytes face issues with yield due to uneven Li-ion distribution and electrochemical instability, leading to reduced capacity and cycle life, as higher oxygen content improves stability but reduces conductivity.
Innovation Solution
The solid electrolyte layer is structured with varying oxygen content from the positive to the negative electrode side, ensuring uniform Li-ion distribution and maintaining high conductivity, with specific atomic percent ranges and crystalline or amorphous structures to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxygen content in the solid electrolyte layer is increased, then electrochemical stability to metallic Li is improved, but Li-ion conductivity is reduced
Solution Approach 1:
The solid electrolyte layer is designed with non-uniform oxygen content distribution, where the oxygen content varies from the positive electrode layer side to the negative electrode layer side. This local variation allows different regions to have optimized properties: higher oxygen content near the negative electrode for stability, and lower oxygen content near the positive electrode for conductivity, thereby resolving the contradiction between electrochemical stability and Li-ion conductivity.
2Productivity
If Li-ion conductivity is nonuniform in the solid electrolyte layer, then Li ions are concentrated at high conductivity portions, but this causes uneven metallic Li distribution and reduced electrode area utilization
Solution Approach 1:
By carefully controlling the oxygen content gradient and maintaining overall uniformity in Li-ion conductivity across the solid electrolyte layer, the patent prevents excessive Li-ion concentration at specific regions. The oxygen content is optimized to balance conductivity uniformity with electrochemical stability, ensuring that Li ions are distributed evenly during charging and discharging, which prevents uneven metallic Li deposition and maintains high electrode area utilization throughout charge-discharge cycles.
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 yield and cycle characteristics of the battery by preventing Li-ion congestion and maintaining high discharge capacity, suitable for portable devices and stacked-cell applications.
Implementation Method 1
sulfide-based solid electrolytes, such as Li2S-P2S5-based electrolytes, with high Li-ion conductivity are used for electrolyte layers arranged between positive electrode layers and negative electrode layers
Implementation Method 2
Li ions are easily concentrated at a portion having a high Li-ion conductivity. Usually, Li ions transferred to the negative electrode layer side during charging the battery are likely to be deposited at the interface in the form of metallic Li
Data Source
Figure 1~2
AI summary
There are provided an electric power generating element which has excellent cycle characteristics and which can be produced in satisfactory yield, and a nonaqueous electrolyte battery including the electric power generating element. In an electric power generating element including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer arranged between these electrode layers, the solid electrolyte layer containing Li, P, S, and O, the O content of the solid electrolyte layer is set so as to be reduced stepwise or continuously from the positive electrode layer side to the negative electrode layer side. When the electric power generating elements each having the structure are produced, most of them provide stable cycle characteristics, i.e., the electric power generating elements are produced in satisfactory yield