Multilayer Solid-State Electrolyte for Faster LiPON Battery Deposition
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Solution Overview
Problem
Conventional solid-state lithium batteries with LiPON electrolytes face low deposition rates, non-conformal coatings, high defect rates due to pinholes, and insufficient lithium ion conductivity, limiting their throughput and performance in high charge/discharge rate applications.
Innovation Solution
A multilayer solid-state electrolyte comprising a carbon-doped lithium phosphorus oxynitride (LiPON) bulk layer and a thin, chemically stable anode interface layer, along with optional cathode and metal interface layers, deposited using pulsed DC sputtering and atomic layer deposition, enhancing lithium ion conductivity and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If LiPON is deposited by RF sputtering, then a solid electrolyte layer is formed, but the deposition rate is low and the coating is non-conformal with high defect rates
Solution Approach 1:
The patent divides the single-layer electrolyte into a multilayer structure with distinct functional layers: a bottom interface layer (10-50 nm) for conformal coverage and defect prevention, a bulk electrolyte layer (1-3 μm) for ion conduction, and an optional top interface layer. This segmentation allows each layer to be optimized for its specific function, resolving the contradiction between coating quality and deposition speed.
Solution Approach 2:
The patent applies different materials and deposition conditions to different layers: the bottom interface layer uses materials and conditions optimized for conformal coverage and defect prevention, while the bulk layer uses conditions optimized for high-rate deposition. This local optimization resolves the contradiction by allowing high deposition rates in the bulk layer while maintaining coating quality in the interface layer.
2Reliability
If a thicker LiPON layer (2 μm) is used to avoid pinholes and electrical leakage, then reliability improves, but deposition time increases to at least 8 hours
Solution Approach 1:
The patent segments the electrolyte into a thin bottom interface layer (10-50 nm) that provides conformal coverage and defect prevention, combined with a bulk electrolyte layer (1-3 μm) for ion conduction. This segmentation maintains reliability by ensuring defect-free interfaces while reducing total deposition time compared to using a uniformly thick layer.
Solution Approach 2:
The patent uses composite multilayer structures with different materials optimized for specific functions: the bottom interface layer uses materials like LiNbO3, LiTaO3, or Li2SiO3 for conformal coverage and defect prevention, while the bulk layer uses LiPON or carbon-doped LiPON for high ion conductivity. This composite approach maintains reliability while reducing deposition time.
3Device complexity
If conventional LiPON electrolyte is used, then a simple single-layer structure is achieved, but lithium ion conductivity is insufficient for high charge/discharge rate applications
Solution Approach 1:
The patent employs composite multilayer electrolyte structures where the bulk electrolyte layer uses high-ion-conductivity materials such as LiPON, carbon-doped LiPON, Li2SiO3, LiNbO3, or LiTaO3. The bottom interface layer uses materials optimized for conformal coverage. This composite structure achieves high lithium ion conductivity necessary for high charge/discharge rates while maintaining structural integrity.
Solution Approach 2:
The patent modifies the electrolyte structure by introducing multiple layers with different compositions and thicknesses, and by doping LiPON with carbon to enhance ion conductivity. These parameter changes enable the electrolyte to achieve the high lithium ion conductivity required for high charge/discharge rate applications while maintaining a manageable structural complexity.
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 multilayer electrolyte achieves higher lithium ion conductivity, faster deposition, and lower defect rates, enabling higher throughput and improved charge/discharge performance in solid-state and thin film batteries.
Implementation Method 1
deposited using pulsed DC sputtering and atomic layer deposition
Implementation Method 2
deposited using pulsed DC sputtering and atomic layer deposition
Data Source
AI summary
A multilayer solid-state electrolyte, solid-state battery cells including the same, and methods of making the electrolyte and the battery cells are disclosed. The multi-layer solid-state electrolyte includes a solid bulk electrolyte layer comprising carbon-doped lithium phosphorus oxynitride (LiPON) or WO3+x (where 0≤x≤1), and a solid anode interface layer comprising LiPON or a metal oxide that forms a stable complex oxide with lithium oxide and conducts lithium ions when lithiated. The anode interface layer has a thickness less than that of the bulk electrolyte layer. The method of making the multi-layer solid-state electrolyte includes depositing one of the solid bulk electrolyte layer and the solid anode interface layer on an active layer of a battery cell, then depositing the other layer on the one layer. As for the solid-state electrolyte, the anode interface layer has a thickness less than that of the bulk electrolyte layer.