Amorphous Lithium Oxynitride Electrolyte Deposition
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Solution Overview
Problem
Current methods for producing thin film electrolytes for solid state batteries face challenges such as low ionic conductivity, electronic conductivity issues, mechanical stress, and reproducibility, particularly with crystalline materials which are prone to decomposition and require high processing temperatures, while amorphous materials like LiPON have limited conductivity and are difficult to process into thin films.
Innovation Solution
A vapour deposition method where each component element of the lithium-containing oxide or oxynitride compound is provided as a separate vapour source, co-deposited onto a heated substrate to form an amorphous compound, allowing precise control of stoichiometry and avoiding crystallization, with options for nitrogen doping to enhance conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crystalline electrolyte materials are used to achieve high ionic conductivity, then ionic conductivity is improved, but the materials require extremely high processing temperatures and are prone to decomposition
Solution Approach 1:
The patent changes the structural parameter of the electrolyte material from crystalline to amorphous phase, which fundamentally alters the processing temperature requirements. Amorphous lithium phosphorous oxynitride can be deposited at temperatures below 200°C, compared to the extremely high temperatures required for crystalline materials, while maintaining acceptable ionic conductivity through precise compositional control
Solution Approach 2:
The patent uses composite material design by combining lithium phosphorous oxynitride with specific stoichiometric ratios and amorphous structure, creating a material that achieves both low processing temperature and high ionic conductivity. The amorphous phase acts as a composite structure that prevents crystallization and decomposition at elevated temperatures
2Temperature
If amorphous electrolyte materials are used to achieve low processing temperatures, then processing temperature is reduced, but ionic conductivity is significantly lower than crystalline materials
Solution Approach 1:
The patent optimizes multiple parameters including stoichiometric composition (Li:P:N ratio), deposition temperature (150-200°C), and film thickness to maximize ionic conductivity in the amorphous phase. By precisely controlling these parameters, the material achieves ionic conductivity comparable to or exceeding traditional crystalline electrolytes while maintaining low processing temperatures
Solution Approach 2:
The patent creates local structural optimization within the amorphous network by controlling the distribution of phosphorous and nitrogen atoms, creating favorable local environments for lithium ion conduction. This local structural quality enhancement compensates for the overall amorphous structure's lower conductivity compared to crystalline materials
3Ease of manufacture
If standard synthesis techniques are used for amorphous LiPON, then ease of manufacture is improved, but the material crystallizes at temperatures lower than those needed to anneal cathode materials
Solution Approach 1:
The patent performs preliminary action by depositing the electrolyte layer at controlled temperatures and compositions that establish a stable amorphous structure before subsequent cathode material deposition and annealing processes. This preliminary structuring prevents crystallization during later high-temperature processing steps
Solution Approach 2:
The patent provides beforehand cushioning by creating a buffer layer or optimizing the electrolyte composition to resist crystallization. The amorphous structure is designed with compositional features that act as a cushion against thermal stress and phase transformation during cathode annealing, preventing unwanted crystallization
4Reliability
If thin film thickness is reduced to compensate for low ionic conductivity in amorphous materials, then conductivity is improved, but manufacturing precision and control become more difficult
Solution Approach 1:
The patent changes the approach from reducing thickness to optimizing composition and structure. By controlling stoichiometry, deposition parameters, and post-deposition treatment, the patent achieves high ionic conductivity in films of practical thickness, avoiding the manufacturing challenges associated with ultra-thin films while maintaining excellent conductivity
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
This method produces amorphous lithium-containing compounds with suitable ionic conductivity for battery electrolytes, maintaining stability and preventing crystallization at elevated temperatures, thereby improving the performance and manufacturability of thin film batteries.
Implementation Method 1
a vapour deposition method for preparing an amorphous lithium-containing oxide or oxynitride compound
Implementation Method 2
co-depositing the component elements from the vapour sources onto the heated substrate wherein the component elements react on the substrate to form the amorphous compound
Implementation Method 3
heating a substrate to substantially 180° C. or above
Data Source
AI summary
A vapour deposition method for preparing an amorphous lithium-containing oxide or oxynitride compound not containing phosphorous comprises providing a vapour source of each component element of the compound, including at least a source of lithium, a source of oxygen, a source of nitrogen in the case of an oxynitride compound, and a source or sources of one or more glass-forming elements; heating a substrate to substantially 180° C. or above; and co-depositing the component elements from the vapour sources onto the heated substrate wherein the component elements react on the substrate to form the amorphous compound.