All-Solid Battery Anode Composite Layer Against Lithium Precipitation
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Solution Overview
Problem
All-solid secondary batteries face issues with lithium precipitation at the interface between the solid electrolyte and negative electrode layers, leading to short circuits and increased internal resistance, which deteriorate cycle characteristics and high-rate capabilities.
Innovation Solution
A multi-component metal composite is used in the first negative active material layer, with a specific atomic ratio, adjacent to the solid electrolyte layer, to prevent short circuits and enhance adhesion, allowing for uniform lithium diffusion and improved interfacial stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a solid electrolyte layer and negative electrode layer are simply stacked, then the battery structure is simple, but the effective interface area between the layers becomes less than the actual contact area, resulting in increased interfacial resistance and deteriorated cycle characteristics
Solution Approach 1:
The invention introduces a multi-component metal composite layer with specific local composition (M1-M2-M3-X) at the interface between the negative electrode and solid electrolyte. This layer has differentiated properties from the bulk electrode materials, creating a specialized interfacial region that improves contact quality and reduces resistance locally without complicating the overall battery structure.
Solution Approach 2:
The invention uses a multi-component metal composite material comprising M1 (Group 1 or 2 element), M2 (transition metal), M3 (post-transition metal), and X (chalcogen or pnictogen) in specific atomic ratios. This composite material combines multiple elements to achieve synergistic effects that reduce interfacial resistance and improve adhesion between the negative electrode and solid electrolyte layers.
2Quantity of substance
If lithium is allowed to precipitate at the interface between solid electrolyte and negative electrode, then lithium ion storage is achieved, but lithium grows and penetrates the solid electrolyte layer, causing short circuits
Solution Approach 1:
The multi-component metal composite layer acts as an intermediary between the negative electrode and solid electrolyte. It provides a controlled interface that allows lithium ion storage while preventing uncontrolled lithium dendrite growth. The specific composition (M1-M2-M3-X) creates a stable interfacial structure that mediates the interaction between lithium and the solid electrolyte.
Solution Approach 2:
The invention changes the interfacial parameters by introducing a layer with specific atomic ratios (M2M3X/M1M2M3X = 0.5-0.84, M2M3X/M1 = 1-5). These parameter changes in composition and structure create a more stable interface that controls lithium precipitation behavior, allowing storage capacity while preventing dendrite formation and short circuits.
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 solution prevents short circuits, reduces interfacial resistance, and enhances the high-rate characteristics and lifespan of the all-solid secondary battery by ensuring uniform lithium diffusion and stable adhesion between the solid electrolyte and negative electrode layers.
Implementation Method 1
ensuring uniform lithium diffusion
Implementation Method 2
heat treating the pre-first negative active material layer at a temperature of less than 600 °C to prepare a first negative active material layer
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An all-solid secondary battery including: a positive electrode layer including a positive active material; a negative electrode layer including a negative electrode current collector and a first negative active material layer; and a solid electrolyte layer between the positive electrode layer and the negative electrode layer, the solid electrolyte including a solid electrolyte, wherein the first negative active material layer is adjacent to the solid electrolyte layer, the first negative active material layer includes a multi-component metal composite including M1, M2, M3, and X, an atomic ratio of M2M3X to M1M2M3X in the multi-component metal composite is in a range of about 0.5 to about 0.84, and an atomic ratio of M2M3X to M1 ion is in a range of about 1 to about 5.