ALD-Coated Solid-State Electrolytes for Lower-Temperature Sintering
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Solution Overview
Problem
Conventional lithium-ion batteries face safety concerns due to flammable organic electrolytes and Li dendrite growth, while solid state batteries struggle with conductivity and interfacial stability issues related to material processing and integration, particularly with garnet-type solid state electrolytes like LLZO, which require high sintering temperatures and are prone to contamination.
Innovation Solution
Surface modification of solid state electrolyte particles using atomic layer deposition (ALD) with a coating of different metal oxides, such as Al2O3, to enhance ionic conductivity and reduce charge transfer resistance, allowing for lower sintering temperatures without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If garnet-type solid state electrolytes like LLZO are used, then safety is improved by eliminating flammable organic electrolytes, but sintering temperature must be high which increases manufacturing complexity and cost
Solution Approach 1:
The patent applies parameter changes by modifying the surface chemistry of LLZO particles through coating with metal oxides (Al2O3, TiO2, ZnO) and conducting plasma treatments. These surface modifications enable the electrolyte to achieve desired performance at lower sintering temperatures (900-1100°C) while maintaining safety benefits of solid state electrolytes.
Solution Approach 2:
The patent creates composite materials by combining LLZO with metal oxide coatings and conductive additives. The composite structure integrates the safety advantages of solid state electrolytes with enhanced interfacial properties, allowing lower processing temperatures while maintaining reliability.
2Reliability
If surface modification with metal oxide coatings is applied, then ionic conductivity is improved and charge transfer resistance is reduced, but device complexity increases due to additional coating processes
Solution Approach 1:
The patent optimizes coating parameters including thickness (5-50 nm), composition ratios, and deposition methods to achieve effective surface modification with minimal process complexity. The metal oxide coatings are applied in controlled thickness ranges that balance performance improvement with manufacturing simplicity.
3Reliability
If high sintering temperatures are used for LLZO, then density and ionic conductivity are improved, but material degradation and contamination increase
Solution Approach 1:
The patent applies preliminary actions by pre-coating LLZO particles with metal oxide layers before sintering. These protective coatings prevent material degradation and contamination during the sintering process, allowing achievement of high ionic conductivity at reduced temperatures while maintaining material integrity.
Solution Approach 2:
The patent employs inert atmosphere plasma treatments and conducts sintering in controlled atmospheric conditions. This creates an inert environment that prevents oxidation and contamination of the electrolyte material, reducing harmful effects while achieving desired conductivity levels.
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 ALD coating significantly improves ionic conductivity and charge transfer resistance, enabling the use of metallic lithium anodes and high-capacity cathodes, while reducing the need for expensive facilities and minimizing material degradation, thus advancing the development of safe and high-performance solid state batteries.
Implementation Method 1
Surface modification of solid state electrolyte particles using atomic layer deposition (ALD) with a coating of different metal oxides
Data Source
AI summary
A product, according to one general aspect, includes solid state electrolyte particles, each particle individually having a coating thereon, the coating comprising a first metal oxide in a first layer and a second metal oxide in a second layer. The first and second metal oxides are different. A method, according to one general aspect, includes fabricating a product using a powder of solid state electrolyte particles, each particle being coated with a coating formed via 15 cycles or less of atomic layer deposition, the coating comprising a first metal oxide in a first layer and a second metal oxide in a second layer. The first and second metal oxides are different.