All-Solid Battery Current Collector Sulfide Reaction Prevention
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Solution Overview
Problem
The capacity of all-solid batteries is decreased due to the generation of sulfur compounds when metals like Cu, Fe, Ni, Co, or Ti react with sulfide solid electrolytes during the manufacturing process, especially at high temperatures, leading to reduced lithium ion insertion and release.
Innovation Solution
The all-solid battery design avoids generating sulfur compounds by using a metal negative electrode current collector that does not react with the sulfide solid electrolyte at elevated temperatures, and a method where the contact portion of the negative electrode layer and current collector is not heated above specific temperatures (e.g., 100°C for Cu and 125°C for Fe) to prevent compound formation, and employing a mock current collector to further suppress reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a metal negative electrode current collector (Cu, Fe, Ni, Co, Ti) is used in contact with sulfide solid electrolyte during manufacturing, then the battery can be produced with standard manufacturing processes, but sulfur compounds are generated due to chemical reactions at elevated temperatures, causing capacity decrease
Solution Approach 1:
An insulating material layer is introduced as an intermediary between the metal current collector and the sulfide solid electrolyte. This intermediate layer prevents direct chemical reaction between the metal and sulfur while allowing the manufacturing process to proceed with standard materials and methods, thus resolving the contradiction between ease of manufacture and battery capacity retention
Solution Approach 2:
The insulating material layer is applied in advance to the metal current collector surface before assembling the battery components. This preliminary protective action prevents the harmful chemical reaction between metal and sulfide solid electrolyte from occurring during subsequent high-temperature manufacturing processes, thereby preserving battery capacity while maintaining manufacturing feasibility
2Productivity
If the negative electrode layer and current collector are heated at high temperatures during manufacturing, then the battery structure is consolidated and manufacturing is completed, but the reaction between metal and sulfide solid electrolyte is promoted, generating sulfur compounds
Solution Approach 1:
The insulating material layer serves as a thermal and chemical barrier during the high-temperature manufacturing process. It allows the necessary heat treatment for structural consolidation to proceed while blocking the direct contact between metal and sulfide solid electrolyte, thus enabling productive manufacturing without generating harmful sulfur compounds
Solution Approach 2:
The insulating material layer creates a chemically inert environment between the reactive metal current collector and the sulfide solid electrolyte during high-temperature processing. This protective barrier allows thermal consolidation to occur without promoting unwanted chemical reactions, maintaining both manufacturing efficiency and product quality
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 approach prevents the formation of sulfur compounds, thereby maintaining or enhancing the battery's capacity by ensuring that the metal and sulfide solid electrolyte do not react, resulting in improved lithium ion insertion and release characteristics.
Implementation Method 1
a sulfur compound that is generated by a reaction of the metal contained in the negative electrode current collector and the sulfide solid electrolyte contained in the negative electrode layer
Implementation Method 2
the contact portion of the negative electrode layer and current collector is not heated above specific temperatures (e.g., 100°C for Cu and 125°C for Fe) to prevent compound formation
Data Source
AI summary
A method is provided for preparing an all-solid battery that at least includes a negative electrode layer containing a negative electrode active material and a sulfide solid electrolyte, and a negative electrode current collector containing a metal that is in contact with the negative electrode layer and can react with the sulfide solid electrolyte, in which a sulfur compound generated by a reaction of the metal contained in the negative electrode current collector and the sulfide solid electrolyte contained in the negative electrode layer is not present in a contact portion of the negative electrode layer and the negative electrode current collector.