Cubic Garnet Solid Electrolyte via Two-Step Calcination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing garnet-type solid electrolytes have low mass productivity and a small garnet powder content due to high-temperature sintering, resulting in low ionic conductivity and high grain boundary resistance, which limits their application in all-solid-state batteries.
Innovation Solution
A method for producing garnet powder with a cubic-phased crystal structure using a two-step calcination process and a hot press process to create a solid electrolyte sheet with improved ionic conductivity, involving the preparation of a mixture of Li2CO3, La2O3, ZrO2, and Al2O3, followed by calcination and grinding, and then hot pressing the garnet powder to form a dense, impurity-free solid electrolyte sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high-temperature sintering is used to form garnet pellets, then phase changes and composition uniformity are secured, but mass productivity is very low and garnet powder content is small
Solution Approach 1:
The patent changes the sintering temperature parameter from conventional high temperatures (900-1400°C) to a lower temperature range (1000-1200°C), and adjusts the sintering time parameter to achieve optimal balance between composition uniformity and productivity. This parameter optimization allows sufficient phase transformation while reducing energy consumption and improving mass productivity
Solution Approach 2:
The patent performs preliminary preparation of garnet powder with controlled particle size and composition before sintering. The raw materials are pre-mixed and pre-formed into pellets with specific density and porosity characteristics, ensuring uniform composition distribution before the sintering process begins, which facilitates faster and more efficient sintering
2Stability of the object's composition
If high-temperature sintering is used for 6 hours or longer, then phase changes are secured, but lithium volatilization occurs and productivity decreases
Solution Approach 1:
The patent optimizes the sintering temperature parameter to a specific range (1000-1200°C) that is sufficient to achieve complete phase transformation to cubic garnet structure but remains below the lithium volatilization threshold. The sintering time parameter is optimized to 6 hours or longer to ensure thorough phase change while maintaining temperature control to prevent lithium loss
Solution Approach 2:
The patent employs an inert atmosphere (such as nitrogen or argon) during the sintering process to create a protective environment that prevents lithium volatilization. The inert gas atmosphere suppresses lithium vapor escape and prevents oxidation, allowing extended sintering time for complete phase transformation without material loss
3Stability of the object's composition
If oxide-type solid electrolyte is used, then stability with respect to moisture is improved, but ionic conductivity is lower than sulfide-based electrolytes
Solution Approach 1:
The patent creates a composite garnet-based solid electrolyte system that combines the advantages of oxide-type stability with enhanced ionic conductivity. The cubic-phase lithium lanthanum zirconate garnet (LLZ) is synthesized with controlled doping and microstructure to achieve high ionic conductivity while maintaining the inherent moisture stability of oxide materials
Solution Approach 2:
The patent modifies the ionic conductivity of the oxide-type garnet electrolyte by controlling the sintering parameters (temperature, time, atmosphere) to achieve optimal density and grain boundary characteristics. The cubic phase composition is optimized through parameter control to maximize lithium ion conductivity while preserving the moisture stability inherent to oxide structures
4Stability of the object's composition
If garnet pellets are used to prevent lithium volatilization, then phase changes are secured, but the proportion of garnet secured is less than 20% by weight
Solution Approach 1:
The patent optimizes the sintering temperature parameter to a range (1000-1200°C) that achieves complete phase transformation to cubic garnet while minimizing lithium volatilization. This parameter optimization ensures that the majority of the starting material transforms into desired garnet phase, achieving garnet powder content exceeding 20% by weight
Solution Approach 2:
The patent uses an inert atmosphere during sintering to prevent lithium volatilization and oxidation, ensuring high conversion efficiency of starting materials to garnet phase. This creates optimal conditions for maximizing garnet powder yield while maintaining phase purity and composition uniformity
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 method achieves a high yield of garnet powder with a cubic-phased crystal structure, significantly improving ionic conductivity and enabling the production of solid electrolyte sheets with enhanced performance compared to existing technologies.
Implementation Method 1
a solid electrolyte sheet using a hot press and a manufacturing method thereof
Implementation Method 2
a method for producing garnet powder with a cubic-phased crystal structure using a two-step calcination process
Data Source
AI summary
The present disclosure relates to garnet powder, a manufacturing method thereof, a solid electrolyte sheet using a hot press, and a manufacturing method thereof. In particular, the present disclosure provides a method for manufacturing Li7La3Zr2O12 (LLZ) garnet powder including preparing a mixture by first dry mixing Li2CO3, La2O3, ZrO2, and Al2O3. The mixture is first calcinated for 5 to 7 hours in a temperature range of 800 to 1000° C. The calcinated mixture is ground to a powder with an average particle size of 1 to 4 μm through dry grinding. A cubic-phased LLZ garnet powder is prepared by second calcinating the ground mixture for 10 to 30 hours in a temperature range of 1100 to 1300° C.