Multiphase Garnet Electrolytes With Inclusions for Better Sintering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current solid-state Li ion batteries face limitations due to instability and secondary phase formation in existing electrolyte materials, which hinder their commercialization, particularly with lithium-stuffed garnet-based electrolytes that require phase purity and specific doping levels 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% volume and secondary phases 30-0.1% volume, exceeding the solubility limit of Al in LLZO, and processed by calcining at temperatures above 800°C to enhance stability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium-stuffed garnet electrolyte is doped with Al and/or Al2O3 to increase ionic conductivity, then Li+ ionic conductivity is improved, but secondary crystalline phases precipitate when doping exceeds solubility limit
Solution Approach 1:
The patent changes the chemical composition parameters by doping LLZO with Al and Al2O3 at controlled concentrations (0.01-0.5 moles each per mole of LLZO) to optimize ionic conductivity while preventing secondary phase precipitation. This parameter optimization resolves the contradiction between improving conductivity and maintaining phase purity.
Solution Approach 2:
The patent creates a composite electrolyte material combining LLZO with controlled amounts of Al and Al2O3 dopants. This composite approach allows the material to benefit from enhanced ionic conductivity through doping while maintaining structural stability and phase purity through controlled composition within solubility limits.
2Productivity
If higher amounts of Al and Al2O3 are added to garnet electrolyte, then ionic conductivity increases, but insoluble secondary crystalline phases form
Solution Approach 1:
The patent optimizes the doping parameters by limiting Al and Al2O3 content to specific ranges (0.01-0.5 moles per mole of LLZO) that maximize ionic conductivity while remaining below the solubility limit to prevent harmful secondary phase precipitation. This parameter control resolves the contradiction between productivity improvement and harmful factor prevention.
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 approach results in improved electrochemical and processing properties, including mechanical strength, stability between 0-4.5V, and increased lithium ion conductivity, overcoming the limitations of phase purity and stability in existing garnet-based electrolytes.
Implementation Method 1
cubic Li7La3Zr2O12, only, or cubic Li7La3Zr2O12 doped with the minimal amount of Al and/or Al2O3 that will not form secondary crystalline phases or inclusions in the primary cubic Li7La3Zr2O12 phase
Implementation Method 2
processed by calcining at temperatures above 800°C to enhance stability and conductivity
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.