Lithium-Stuffed Garnet Green Tape Casting for Crack-Free Sintered Films
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Solution Overview
Problem
Solid state ion conducting ceramics, such as lithium-stuffed garnet materials, face challenges during the formation and sintering of green films, including sticking to substrates, cracking, warping, and brittleness, which affects their quality and usability in electrochemical devices.
Innovation Solution
A method involving the preparation of a slurry with a lithium-stuffed garnet source powder, binders, solvents, and sintering aids, followed by casting and drying to form a green tape, which is then sintered to produce high-density, low-porosity thin films with improved surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to form green films of solid state ion conducting ceramics, then the films can be produced, but they tend to stick to the substrate, crack, warp, or become too brittle to handle
Solution Approach 1:
The patent modifies the chemical composition parameters of the green film by incorporating specific organic additives (binders, plasticizers, dispersants) and controlling the solvent-to-powder ratio. These parameter changes alter the physical properties of the green film, making it more flexible and less brittle while maintaining adhesion to the substrate during sintering, thereby resolving the contradiction between film quality and handling ease.
Solution Approach 2:
The patent introduces organic intermediary substances (binders and plasticizers) that act as mediators between the ceramic powder particles and the substrate. These intermediaries provide temporary flexibility and adhesion during the sintering process, preventing cracking and warping, and enabling easier handling of the green film without compromising the final sintered product quality.
2Manufacturing precision
If green films are sintered under conventional conditions, then densification occurs, but the films crack, warp, or have surface deteriorations
Solution Approach 1:
The patent performs preliminary actions by incorporating organic additives and controlling the green film formulation before sintering. The binders and plasticizers are added in advance to prevent cracking and warping during the sintering process. The dispersants are pre-added to ensure uniform particle distribution, which prevents surface deteriorations and maintains film integrity throughout the sintering process, thereby achieving both high manufacturing precision and reliability.
Solution Approach 2:
The patent changes the chemical and physical parameters of the green film composition, including the addition of organic binders, plasticizers, and dispersants, as well as controlling the solvent content and particle size distribution. These parameter changes enable the film to withstand sintering stresses without cracking or warping, while achieving high density and excellent surface quality, thus resolving the contradiction between manufacturing precision and film integrity.
3Quantity of substance
If higher solid loading is used in green tapes, then sintered films achieve higher density and lower porosity, but the casting and sintering processes become more difficult
Solution Approach 1:
The patent introduces organic intermediary substances (binders, plasticizers, and dispersants) that facilitate the handling and processing of high solid loading green tapes. These intermediaries reduce the viscosity and improve the flowability of the slurry, making casting easier despite the high powder content. During sintering, they provide flexibility to prevent cracking and warping, thereby enabling high solid loading to be achieved without significantly compromising processing ease.
Solution Approach 2:
The patent modifies the composition parameters of the green tape by optimizing the ratio of solid powder to organic additives and solvent. By carefully controlling these parameters and introducing specific functional additives, the patent achieves high solid loading while maintaining adequate slurry fluidity for easy casting and sintering, thus resolving the contradiction between quantity of substance and ease of manufacture.
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 results in sintered thin films with reduced porosity, higher density, and improved surface quality, suitable for use in electrochemical devices without further processing, enhancing their performance and handling characteristics.
Implementation Method 1
drying the green tape
Implementation Method 2
sintering the green tape to form a sintered thin film
Data Source
AI summary
Set forth herein are processes and materials for making ceramic thin films by casting ceramic source powders and precursor reactants, binders, and functional additives into unsintered thin films and subsequently sintering the thin films under controlled atmospheres and on specific substrates.