Composite Solid-State Electrolyte for Low-Temperature Sintering
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Solution Overview
Problem
Existing methods for producing garnet-type oxide solid electrolytes require high-temperature sintering, leading to issues like additional interfaces and side reactions, limiting the reduction of sintering temperature and affecting conductivity.
Innovation Solution
A composite solid-state electrolyte composed of a cubic garnet phase and a pyrochlore phase, with a glass phase dispersed in a matrix, is sintered at a low temperature (550°C or less) to maintain high conductivity, using a mixture of first and second solid-state electrolyte precursors with controlled crystallization temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature sintering (about 1200°C) is performed to achieve high Li ion conductivity in garnet-type oxide solid electrolyte, then ionic conductivity is improved, but manufacturing complexity and energy consumption increase
Solution Approach 1:
The patent changes the sintering temperature parameter from conventional high temperature (about 1200°C) to low temperature (550°C or less) by using a composite solid-state electrolyte system consisting of a first solid-state electrolyte (cubic garnet phase with Li ion conductivity) and a second solid-state electrolyte (glass phase) in a specific volume ratio (3:2 to 99.5:0.5), thereby achieving high ionic conductivity without high-temperature sintering
Solution Approach 2:
The patent creates a composite solid-state electrolyte comprising two different solid-state electrolyte materials: a first solid-state electrolyte (cubic garnet phase) and a second solid-state electrolyte (glass phase), which work synergistically to enable low-temperature sintering while maintaining high Li ion conductivity
2Use of energy by stationary object
If sintering temperature is reduced to simplify manufacturing, then energy consumption decreases, but Li ion conductivity deteriorates
Solution Approach 1:
The patent employs a composite structure where the first solid-state electrolyte (cubic garnet phase) provides Li ion conductivity pathways and the second solid-state electrolyte (glass phase) forms a matrix that facilitates ion transport, enabling effective Li ion conduction at low sintering temperatures (550°C or less)
Solution Approach 2:
The patent optimizes the volume ratio parameter between the first and second solid-state electrolytes (3:2 to 99.5:0.5) to balance the structural framework provided by the cubic garnet phase and the ion-conducting matrix provided by the glass phase, achieving optimal ionic conductivity at low sintering temperatures
3Stability of the object's composition
If conventional sintering methods are used to maintain material stability, then chemical stability is preserved, but manufacturing precision and density control become difficult at low temperatures
Solution Approach 1:
The patent controls the crystallization temperature parameter of the first solid-state electrolyte to be lower than that of the second solid-state electrolyte, enabling selective crystallization during low-temperature sintering (550°C or less) and achieving precise density control (80-95% relative density) while maintaining chemical 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 composite electrolyte achieves high ionic conductivity (1×10−5 to 1×10−3 S/cm) and density (80-95% relative density) without high-temperature sintering, enabling improved energy density and cycle characteristics in lithium batteries.
Implementation Method 1
A crystallization temperature T1 of the first solid-state electrolyte may be less than a crystallization temperature T2 of the second solid-state electrolyte. The crystallization temperature of the first solid-state electrolyte may be about 300° C. to about 450° C.
Implementation Method 2
a heat treatment temperature T of the composite solid-state electrolyte-forming composition may be 550° C. or less
Data Source
AI summary
A composite solid-state electrolyte, a method of preparing the same, and a lithium battery including the same. The composite solid-state electrolyte includes a first solid-state electrolyte including a cubic garnet phase and a pyrochlore phase, and a second solid-state electrolyte including a glass phase, and a volume of the first solid-state electrolyte is greater than that of the second solid-state electrolyte, based on a total volume of the composite solid-state electrolyte.