Garnet Composite Electrolyte With Lithium-Rich Grain Boundaries
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Solution Overview
Problem
Conventional lithium-garnet electrolytes in solid-state lithium batteries suffer from insufficient contact between the Li anode and garnet electrolyte, leading to low critical current density and potential short circuiting due to poor lithium wettability and surface impurities, which existing solutions like H3PO4 acid treatments and interlayer modifications fail to adequately address.
Innovation Solution
A lithium-garnet composite ceramic electrolyte is developed by incorporating a lithium-rich minor phase, such as LixTiO(x+4)/2, during the sintering process, which enhances grain boundary bonding and blocks lithium dendrite growth, achieving a critical current density of at least 1.5 mA·cm−2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium-rich minor phase is added to enhance grain boundary bonding, then critical current density improves, but manufacturing complexity increases
Solution Approach 1:
The patent merges the formation of lithium-rich secondary phases directly into the sintering process of the lithium-garnet electrolyte. By co-sintering the garnet precursors with lithium-rich additives (such as SiO2, TiO2, or their lithium compounds) at temperatures between 900-1100°C, the secondary phases form in-situ at grain boundaries, eliminating separate manufacturing steps and reducing overall manufacturing complexity while achieving the desired critical current density improvement
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 ceramic electrolyte significantly improves the critical current density and prevents lithium dendrite growth, ensuring stable battery performance and extending the battery's operational lifespan by enhancing bonding at the grain boundaries and simplifying the sintering process.
Implementation Method 1
a sintered composite ceramic, comprises: a lithium-garnet major phase; and a lithium-rich minor phase
Implementation Method 2
enhances grain boundary bonding of Li-garnet electrolytes
Data Source
AI summary
A sintered composite ceramic includes: a lithium-garnet major phase; and a lithium-rich minor phase, such that the lithium-rich minor phase has LixTiO(x+4)/2, with 0.66≤x≤4. The sintered composite ceramic may exhibit a relative density of at least 90% of a theoretical maximum density of the ceramic, an ionic conductivity of at least 0.35 mS·cm−1, or a critical current density (CCD) of at least 1.0 mA·cm−2.