Bi-Substituted Garnet Solid Electrolyte Low-Temperature Sintering
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Solution Overview
Problem
Existing methods for producing cubic system garnet type Li7La3Zr2O12 require severe firing conditions, leading to unwanted reactions with electrode materials and inefficiencies in lithium ion battery production, as they often result in mixed phases rather than single-phase solid electrolytes.
Innovation Solution
A solid electrolyte material with a cubic system garnet crystal structure, where La sites are partly or entirely substituted by Bi, and Al is added, allowing for sintering at lower temperatures (900-1150°C) for shorter times, preventing unwanted reactions and ensuring a single-phase cubic Li7La3Zr2O12 formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If severe firing conditions (high temperature, long time) are employed to produce cubic system garnet type Li7La3Zr2O12, then a sintered body with desired lithium ion conductivity can be obtained, but unwanted reactions with electrode materials occur and production efficiency decreases
Solution Approach 1:
The patent changes the chemical composition parameters by introducing Al substitution for Zr and Bi substitution for La in the garnet structure. This compositional modification enables the material to achieve desired lithium ion conductivity under milder firing conditions (lower temperature and shorter time), thereby resolving the contradiction between reliability and productivity
Solution Approach 2:
The patent creates a composite solid electrolyte material by combining multiple elements (Li, La, Zr, Al, Bi) in a modified garnet structure. This composite approach with specific elemental ratios enables both high lithium ion conductivity and stability under reduced firing conditions, eliminating unwanted reactions while maintaining performance
2Stability of the object's composition
If severe firing conditions are used to form single-phase cubic Li7La3Zr2O12, then the desired crystal structure is achieved, but the firing time and temperature increase leading to higher production costs
Solution Approach 1:
The patent modifies the stoichiometric composition by incorporating Al at Zr sites and Bi at La sites with specific concentration ranges. This parameter change in chemical composition facilitates single-phase cubic garnet formation at lower temperatures and shorter times, directly addressing the contradiction between composition stability and time loss
Solution Approach 2:
The patent performs preliminary compositional design by pre-calculating and preparing the exact ratios of Li, La, Zr, Al, and Bi elements before firing. This preliminary action ensures that the material achieves single-phase cubic structure during the shortened firing process, eliminating the need for prolonged high-temperature treatment
3Manufacturing precision
If high temperature firing is employed to produce cubic garnet type solid electrolyte, then the crystal structure is formed, but reactions with cathode and anode materials occur during battery assembly
Solution Approach 1:
The patent changes the chemical parameters by substituting Al for Zr and Bi for La in the garnet structure, creating a composition that forms the cubic crystal structure at lower temperatures. This parameter change prevents unwanted reactions with electrode materials while maintaining the desired crystal structure, as the lower processing temperature reduces chemical reactivity
Solution Approach 2:
The patent uses a composition formulation that achieves stable cubic garnet phase at reduced temperatures, effectively replacing the need for severe high-temperature processing. This approach eliminates harmful high-temperature reactions with electrode materials while maintaining manufacturing precision for crystal structure formation
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
This approach enables the production of a sintered body with desired lithium ion conductivity while suppressing reactions with electrode materials, enhancing production efficiency and cost-effectiveness by maintaining a single-phase cubic system garnet crystal structure.
Implementation Method 1
firing at lower temperature in shorter time to suppress the reaction between these materials
Implementation Method 2
the oxide has a cubic system garnet crystal structure wherein La sites are partly or entirely substituted by Bi
Data Source
AI summary
A material capable of producing a sintered body of cubic system garnet type Li7La3Zr2O12 as a solid electrolyte having specified ion conductivity by firing at relatively low temperature in short time. The material for the solid electrolyte is an oxide containing Li, La, Zr and Bi, and the oxide has a cubic system garnet crystal structure where La sites are partly or entirely substituted by Bi.