All-Solid-State Battery Interface Layers for Halide Electrolyte Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Halide-based solid electrolytes in all-solid-state batteries face issues with decomposition at the negative electrode interface, leading to insufficient cycle characteristics due to reactions with the negative electrode active material, and high potential windows on the reduction side, which hinder effective lithium ion flow.
Innovation Solution
An all-solid-state battery design with a negative electrode mixture layer comprising a first phase and a second phase, where the first phase has a higher concentration of specific elements (F, Cl, Br, or I) than the solid electrolyte layer, and the second phase has a lower concentration, creating a layered structure to stabilize the interface and prevent electrolyte decomposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a halide-based solid electrolyte is used in an all-solid-state battery, then high ion conductivity is achieved, but decomposition occurs at the negative electrode interface due to reactions with the negative electrode active material
Solution Approach 1:
A protective coating layer is introduced as an intermediary between the halide-based solid electrolyte and the negative electrode active material. This coating layer prevents direct contact and reaction between the electrolyte and active material, thereby preventing decomposition while maintaining high ion conductivity through the electrolyte.
Solution Approach 2:
The chemical composition and physical properties of the interface region are modified by introducing a protective coating layer with specific material characteristics. This changes the interfacial parameters to be more compatible with both the halide-based solid electrolyte and negative electrode active material, preventing decomposition reactions.
2Stability of the object's composition
If the solid electrolyte interface is stabilized with additional layers, then decomposition is prevented, but the device structure becomes more complex
Solution Approach 1:
Instead of modifying the entire electrolyte structure, the protective coating is applied locally only at the negative electrode interface where decomposition occurs. This localized approach provides necessary protection while minimizing additional structural complexity.
Solution Approach 2:
The protective coating is applied asymmetrically - only at the negative electrode interface where decomposition is problematic, rather than uniformly throughout the entire battery structure. This asymmetric modification addresses the specific problem area without unnecessarily complicating other parts of the device.
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 design enhances cycle characteristics by preventing solid electrolyte decomposition and maintaining effective lithium ion flow, thereby improving the battery's discharge capacity and reversible capacity.
Implementation Method 1
a solid electrolyte layer (10) containing a halide-based solid electrolyte
Implementation Method 2
the first phase and the second phase contain a Li element and an X element which is at least one halogen element... an X element concentration in the first phase is higher than an X element concentration in the solid electrolyte layer, and an X element concentration in the second phase is lower than the X element concentration in the first phase
Data Source
AI summary
An all-solid-state battery includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. A negative electrode mixture layer of the negative electrode layer contains either one or both of a negative electrode active material and a carbon material, a first phase in contact with at least a part of the negative electrode active material and the carbon material, and a second phase in contact with at least a part of the first phase. The first and second phases contain a Li element and an X element which is at least one halogen element selected from the group consisting of F, Cl, Br, and I. An X element concentration in the first phase is higher than in the solid electrolyte layer. An X element concentration in the second phase is lower than the in the first phase and in the solid electrolyte layer.