Lithium Metal Negative Electrode Structure for Lower Interface Resistance
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Solution Overview
Problem
Current negative electrodes in electrochemical devices, such as batteries, have insufficient electrical characteristics, necessitating an improvement in their configuration to enhance performance.
Innovation Solution
A negative electrode configuration comprising an active material layer with a lithium metal layer, an intermediate layer containing lithium and oxygen, and a surface layer with lithium, oxygen, and carbon, topped with an inorganic solid electrolyte layer containing a distinct characteristic element, formed through a rolling process in a reduced-pressure environment, which reduces interface resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lithium metal foil surface is subjected to acid solution treatment or etching process, then a solid electrolyte film is formed on the surface, but the electrical characteristics remain insufficient
Solution Approach 1:
The negative electrode is segmented into multiple functional layers: a lithium metal layer, an intermediate layer containing lithium and oxygen, and a surface layer containing lithium, oxygen, and carbon. This segmentation allows each layer to perform its specific function, with the intermediate layer serving as a transition zone that improves overall electrical characteristics without requiring complex acid treatment or etching processes.
Solution Approach 2:
The patent employs composite material structure where the intermediate layer combines lithium and oxygen elements to create a material with optimized electrical properties. This composite approach achieves superior electrical characteristics compared to pure lithium metal or conventional solid electrolyte films, while maintaining manufacturing simplicity through direct layer formation rather than post-processing treatments.
2Reliability
If additional ion conductive layers are added to improve electrical characteristics, then performance enhances, but device complexity increases
Solution Approach 1:
The intermediate layer is designed to perform multiple functions simultaneously: it serves as an ion conductive pathway, provides structural support, and facilitates lithium ion transport between the lithium metal layer and the surface layer. This multi-functionality eliminates the need for separate ion conductive layers, maintaining device simplicity while achieving high ion conductivity and electrical performance.
Solution Approach 2:
The patent merges the functions of the lithium metal layer, the intermediate layer, and the surface layer into a unified negative electrode structure. The intermediate layer is integrated between the lithium metal and surface layer, creating a seamless three-layer system where each layer contributes to overall ion conductivity and electrical characteristics, eliminating the need for additional external ion conductive layers.
Data Source
AI summary
A negative electrode includes an active material layer and an inorganic solid electrolyte layer. The inorganic solid electrolyte layer is on the active material layer. The active material layer includes, in order from a side far from the inorganic solid electrolyte layer, a lithium metal layer, an intermediate layer, and a surface layer. As constituent elements, the intermediate layer includes lithium and oxygen, the surface layer includes lithium, oxygen, and carbon, and the inorganic solid electrolyte layer includes a characteristic element different from lithium, oxygen, and carbon. In an element analysis result based on XPS, a ratio of an abundance of lithium to an abundance of carbon is greater than 2 at any depth within a range from a first intersection to a second intersection. The first intersection is where a characteristic element spectrum intersects a carbon spectrum. The second intersection is where a lithium spectrum intersects an oxygen spectrum.