Passivation Layer for Sulfide Glass Electrolyte Stability
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Solution Overview
Problem
Lithium and sodium-containing solid electrolyte compositions, such as glass, glass-ceramic, and ceramic materials, are not thermodynamically stable when in direct contact with lithium or sodium metal anodes, leading to degradation of battery cell performance during repeated discharge and recharge cycles.
Innovation Solution
A thin passivating layer of aluminum oxide or other suitable oxides is applied to the metal anode-contacting surface of these electrolyte compositions using atomic layer deposition (ALD) to enhance stability and prevent unwanted side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin passivating layer of aluminum oxide is applied to the electrolyte surface using atomic layer deposition, then the chemical stability of the electrolyte interface is improved, but the device complexity and manufacturing precision requirements increase
Solution Approach 1:
A thin passivating layer of aluminum oxide is deposited on the electrolyte surface before the electrolyte comes into contact with the lithium metal anode. This preliminary protective action prevents unwanted side reactions and improves the chemical stability of the interface during battery operation.
Solution Approach 2:
The aluminum oxide layer acts as an intermediary between the electrolyte and the lithium metal anode. This intermediate layer prevents direct contact and unwanted reactions between the electrolyte and the metal anode, while still allowing lithium ion transport to occur.
2Duration of action of stationary object
If a thin passivating layer is applied to prevent unwanted side reactions, then the operational lifespan of the battery cell is extended, but the manufacturing precision and process control requirements increase
Solution Approach 1:
The atomic layer deposition process allows for precise control of the passivation layer thickness by controlling the number of deposition cycles. Each cycle deposits a known thickness, so the total thickness can be precisely controlled by changing the number of cycles, thereby managing manufacturing precision requirements.
Solution Approach 2:
The mechanical process of directly contacting the electrolyte with the lithium metal anode is replaced by a chemically engineered interface with a passivating layer. This substitution prevents mechanical and chemical degradation, extending the operational lifespan of the battery cell.
3Productivity
If the electrolyte composition is made more ion-conductive, then the battery performance is improved, but the thermodynamic stability at the metal electrode interface deteriorates
Solution Approach 1:
The interface between the electrolyte and the lithium metal anode is segmented into two distinct layers: the bulk electrolyte material that provides ion conduction, and a thin surface passivating layer that provides chemical stability. This segmentation allows each layer to optimize its function independently.
Solution Approach 2:
The electrolyte is given different properties at different locations: the bulk material is optimized for high ion conductivity, while the surface layer is optimized for chemical stability. This local differentiation of properties resolves the contradiction between performance and stability.
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 passivation layer improves the chemical stability of the electrolyte interfaces, allowing for effective lithium or sodium ion transport and preventing dendrite formation, thereby extending the battery cell's operational lifespan and preventing short circuits.
Implementation Method 1
a thin passivating atomic layer deposition is applied to the intended contacting surface(s) of a vulnerable lithium-containing electrolyte composition
Implementation Method 2
a thin passivating atomic layer deposition is applied to the intended contacting surface(s) of a vulnerable lithium-containing electrolyte composition
Data Source
AI summary
Certain glass, glass-ceramic, and ceramic electrolyte bodies formed from lithium or sodium sulfides and glass-forming sulfides, sulfoxides and/or certain glass-forming oxides provide good conductivity of lithium ions or sodium ions for use in lithium metal electrode or sodium metal electrode battery cells. The stability of the lithium or sodium metal anode-glass electrolyte interface is improved by forming a metal oxide passivation layer by atomic layer deposition on the facing surface of the electrolyte and activating the coating by contact of the passivated surface with the lithium or sodium electrode material.