Lithium-Garnet Composite Electrolyte for Dendrite Suppression
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Solution Overview
Problem
Conventional lithium-garnet electrolytes in solid-state batteries face challenges due to insufficient contact between the Li anode and garnet electrolyte, leading to low critical current density and lithium dendrite formation, which limits their application in large-scale electrical equipment.
Innovation Solution
A lithium-garnet composite ceramic electrolyte is developed, comprising a lithium-garnet major phase and a lithium dendrite growth inhibitor minor phase, specifically lithium tungstate, which enhances grain boundary bonding and inhibits lithium dendrite growth, achieved through sintering at temperatures between 750°C to 1500°C with a lithium-to-tungsten molar ratio of ⅓≤x≤6.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium-garnet electrolyte is used in solid-state batteries, then safety concerns are addressed, but insufficient contact between Li anode and garnet electrolyte leads to low critical current density and lithium dendrite formation
Solution Approach 1:
The patent creates a composite electrolyte structure by infiltrating liquid electrolyte into the porous lithium-garnet solid electrolyte. This composite approach combines the safety benefits of solid electrolytes with the high ionic conductivity and wetting properties of liquid electrolytes, achieving both improved safety and critical current density
Solution Approach 2:
The patent utilizes the porous structure of lithium-garnet solid electrolyte as a scaffold for liquid electrolyte infiltration. The pores provide pathways for liquid electrolyte penetration and create extensive contact area with the Li anode, improving both interfacial contact and ionic conductivity while maintaining the structural integrity of the solid electrolyte
2Quantity of substance
If lithium-garnet electrolyte is used, then energy density is improved, but poor lithium wettability and surface impurities cause large polarization and interfacial resistances
Solution Approach 1:
The liquid electrolyte acts as an intermediary substance between the lithium-garnet solid electrolyte and the Li anode. It improves lithium wettability and reduces interfacial resistance by forming a conductive medium that facilitates lithium ion transfer across the interface, eliminating the poor wettability and high resistance issues of pure solid electrolytes
3Ease of manufacture
If LLZO with pores and defects is used, then manufacturing is simplified, but lithium dendrites form and propagate inside the LLZO
Solution Approach 1:
The patent converts the harmful pores and defects in LLZO into beneficial features by infiltrating liquid electrolyte into them. The previously harmful void spaces become conductive pathways filled with liquid electrolyte that suppress dendrite propagation, transforming manufacturing simplicity into a reliable dendrite-resistant structure
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 a critical current density greater than 0.7 mA·cm−2 and a relative density greater than 97%, effectively suppressing lithium dendrite growth and improving the performance of solid-state lithium metal batteries.
Implementation Method 1
sintering at temperatures between 750°C to 1500°C
Data Source
AI summary
A sintered composite ceramic includes a lithium-garnet major phase; and a lithium dendrite growth inhibitor minor phase, such that the lithium dendrite growth inhibitor minor phase comprises lithium tungstate. A method includes sintering a metal oxide component and a garnet component at a temperature in a range of 750° C. to 1500° C. to form a sintered composite ceramic.