Silicon-Containing Anode Layer for Stable Solid-State Lithium Deposition
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Solution Overview
Problem
Conventional all-solid-state batteries face limitations in achieving high critical current densities and stable lithium metal deposition due to kinetic constraints and interfacial issues, leading to potential cell failure and performance degradation.
Innovation Solution
Incorporating a silicon-containing metal layer on the negative electrode current collector with controlled Ns/P ratio, thickness, and morphology, which facilitates controlled lithiation and optimized lithium metal formation, enhancing the critical current density and overall battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used in the negative electrode to achieve high energy density, then the specific energy increases above 350 Wh/kg, but the lithium metal forms an oxide layer due to reactivity and exhibits unstable deposition morphology
Solution Approach 1:
A silicon-containing layer is introduced as an intermediary between the negative electrode current collector and the solid electrolyte. This intermediate layer facilitates controlled lithiation and stabilizes lithium metal deposition, preventing direct contact between lithium metal and the electrolyte interface that would otherwise lead to oxide formation and unstable morphology.
Solution Approach 2:
The patent controls the thickness and composition parameters of the silicon-containing layer to optimize lithium deposition. By adjusting these physical parameters, the layer enables stable lithium metal formation while maintaining high energy density, resolving the contradiction between energy density and deposition stability.
2Reliability
If a solid electrolyte is used to replace liquid electrolyte to improve safety, then the risk of ignition or explosion is reduced, but kinetic limitations arise that restrict critical current density
Solution Approach 1:
The silicon-containing layer acts as a mediator that enhances interfacial contact between the solid electrolyte and electrode, improving ion transport kinetics without compromising the inherent safety advantages of the solid electrolyte system.
Solution Approach 2:
The patent introduces a localized silicon-containing layer at the critical interface region where kinetic limitations occur. This local modification improves critical current density at the electrode-electrolyte interface while maintaining the overall safety benefits of the solid electrolyte system elsewhere in the battery.
3Reliability
If the silicon-containing layer thickness is increased to improve lithium deposition stability, then the critical current density increases, but the charge capacity ratio (Ns/P) becomes unbalanced
Solution Approach 1:
The patent optimizes the thickness parameter of the silicon-containing layer to achieve a balance between improving lithium deposition stability and maintaining an appropriate charge capacity ratio. By precisely controlling this physical parameter, both contradictory requirements are satisfied simultaneously.
Solution Approach 2:
The silicon-containing layer is designed with a thickness that provides sufficient lithiation capacity to stabilize lithium deposition, but is controlled to not excessively consume charge capacity. This partial action approach ensures stability improvement without unbalancing the overall charge capacity ratio.
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 silicon-containing layer improves the critical current density by up to five times at room temperature, enabling stable lithium metal deposition and improved cyclability, safety, and increased energy density.
Implementation Method 1
facilitates controlled lithiation and optimized lithium metal formation
Implementation Method 2
lithium metal is formed on the negative electrode current collector by movement of lithium metal ions from the positive electrode
Data Source
AI summary
Disclosed is a lithium all-solid-state battery and a method for manufacturing the same. The lithium all-solid-state battery includes a positive electrode, a negative electrode current collector, a solid electrolyte layer between the negative electrode current collector and the positive electrode, and a silicon-containing metal layer on a surface of the negative electrode current collector facing the solid electrolyte layer. The lithium metal is formed on the negative electrode current collector by movement of lithium metal ions from the positive electrode to the silicon-containing metal layer on the surface of the negative electrode current collector through charge, and a ratio (Ns/P) of a charge capacity of the silicon-containing metal layer (Ns) to a charge capacity of the positive electrode (P) is less than 0.3.