Multiphase Lithium-Stuffed Garnet Electrolytes for Better Sintering
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Solution Overview
Problem
Current solid-state Li ion batteries face limitations due to instability and incompatibility issues with existing electrolyte, catholyte, and anolyte materials, particularly with lithium-stuffed garnet-based components, which hinder commercialization and require phase-pure cubic lithium-stuffed garnet electrolytes to achieve high ionic conductivity.
Innovation Solution
A multiphase thin film solid-state electrolyte comprising a primary cubic phase lithium-stuffed garnet with secondary phase inclusions, where the primary phase constitutes 70-99.9% of the volume and secondary phases 0.1-30%, specifically designed to enhance electrochemical and mechanical properties, stability, and compatibility with Li metal, exceeding the solubility limit of Al in LLZO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium-stuffed garnet electrolytes are doped with aluminum beyond the solubility limit to enhance ionic conductivity, then lithium ion conductivity is improved, but secondary crystalline phases precipitate causing instability and incompatibility
Solution Approach 1:
The patent changes the chemical composition parameters by doping LLZO with aluminum at concentrations exceeding the conventional solubility limit (x > 0.2 in Li7-3xAlxLa3Zr2O12), thereby transforming the material from phase-pure to multiphase while achieving superior ionic conductivity and electrochemical stability
Solution Approach 2:
The patent creates a composite electrolyte material consisting of a primary cubic lithium-stuffed garnet phase combined with secondary crystalline phases (such as LaAlO3, LiAlO2, La2Zr2O7) that form when aluminum doping exceeds the solubility limit, resulting in a multiphase composite with enhanced overall performance
2Reliability
If phase-pure cubic lithium-stuffed garnet is used to achieve high ionic conductivity, then electrochemical performance is improved, but manufacturing complexity increases due to strict compositional control requirements
Solution Approach 1:
The patent applies excessive action by intentionally adding aluminum dopant beyond the solubility limit, allowing secondary phases to form. This partial deviation from phase-purity requirements actually simplifies manufacturing control while achieving the desired ionic conductivity through the synergistic multiphase 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 solution provides improved electrochemical and processing properties, including enhanced lithium ion conductivity, mechanical strength, and sinterability, overcoming the stability and compatibility issues of existing materials, thus advancing the commercial viability of solid-state batteries.
Implementation Method 1
cubic phase garnet structures have a higher ionic conductivity than tetragonal phase garnet structures
Implementation Method 2
sinterability
Data Source
AI summary
The instant disclosure sets forth multiphase lithium-stuffed garnet electrolytes having secondary phase inclusions, wherein these secondary phase inclusions are material(s) which is/are not a cubic phase lithium-stuffed garnet but which is/are entrapped or enclosed within a lithium-stuffed garnet. When the secondary phase inclusions described herein are included in a lithium-stuffed garnet at 30-0.1 volume %, the inclusions stabilize the multiphase matrix and allow for improved sintering of the lithium-stuffed garnet. The electrolytes described herein, which include lithium-stuffed garnet with secondary phase inclusions, have an improved sinterability and density compared to phase pure cubic lithium-stuffed garnet having the formula Li7La3Zr2O12.