Garnet Ceramic Powder Composition for Low-Temperature Sintering
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Solution Overview
Problem
Conventional garnet-type compounds require high-temperature sintering, leading to lithium volatilization and decomposition, resulting in low ionic conductivity and strength of sintered bodies.
Innovation Solution
A ceramic powder comprising a garnet-type oxide with specific elements, including zirconium, lithium, and lanthanum, combined with compounds like lanthanum oxide and lithium gallate, allows for sintering at lower temperatures to achieve high density and ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high-temperature sintering (exceeding 1100°C) is used to process garnet-type compounds, then sintering can be completed, but lithium volatilization and decomposition occur, resulting in low ionic conductivity and strength
Solution Approach 1:
A glassy phase containing PbO, B2O3, and SiO2 is introduced as an intermediary substance during sintering. This glassy phase acts as a flux that lowers the sintering temperature requirement while preventing lithium volatilization. The glassy phase forms a protective environment that enables densification at lower temperatures (900-1100°C) without the harmful effects of high-temperature processing.
Solution Approach 2:
The invention changes the sintering temperature parameter from conventional high temperatures (>1100°C) to a lower range (900-1100°C) by modifying the chemical composition. The addition of specific oxides (PbO, B2O3, SiO2) alters the thermal and chemical properties of the system, enabling effective sintering at reduced temperatures while maintaining product quality and preventing material loss.
2Ease of manufacture
If high-temperature sintering is used, then sintering can be achieved, but decomposition occurs, resulting in low ionic conductivity
Solution Approach 1:
The glassy phase serves as a protective intermediary that prevents decomposition of the garnet structure during sintering. By lowering the processing temperature and providing a chemically stable environment, the glassy phase preserves the integrity of the lithium lanthanum zirconate structure, ensuring high ionic conductivity in the final product.
Solution Approach 2:
The chemical composition parameters are modified by adding PbO, B2O3, and SiO2, which change the thermal stability and chemical resistance of the sintered body. These compositional changes enable the material to maintain its structure and ionic conductivity properties after sintering, avoiding decomposition issues.
3Ease of manufacture
If high-temperature sintering is used, then sintering can be completed, but the sintered body strength remains low
Solution Approach 1:
The glassy phase acts as a binding intermediary that enhances the strength of the sintered body. During sintering, the glassy phase melts and forms a viscous matrix that binds the ceramic particles together, creating a dense and strong composite structure. This glass-ceramic composite approach significantly improves mechanical strength compared to conventional ceramic sintering.
Solution Approach 2:
The invention creates a composite material system combining crystalline garnet phase (Li7La3Zr2O12) with a glassy phase (PbO-B2O3-SiO2 system). This composite structure leverages the advantages of both phases: the garnet provides ionic conductivity while the glassy phase provides mechanical strength and densification, resulting in a material with superior overall properties.
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 ceramic powder forms a sintered body with high density and ionic conductivity, suitable for all-solid lithium-ion secondary batteries, even at lower sintering temperatures, reducing lithium volatilization and enhancing material strength.
Implementation Method 1
conventional garnet-type compounds must be subjected to heat treatment at a temperature exceeding 1100° C., for example, to obtain sintered bodies
Data Source
AI summary
This invention provides a ceramic powder capable of forming a sintered body having a high density and high ionic conductivity even at a sintering temperature lower than the temperature conventionally used, and provides a battery containing a sintered body of the ceramic powder as a constituent element. The above problem is solved by a ceramic powder containing a garnet-type oxide and compound 1, wherein the garnet-type oxide contains zirconium, lithium, and lanthanum, and compound 1 contains at least one metal element selected from the group consisting of lanthanum, lithium, zirconium, gallium, scandium, yttrium, cerium, aluminum, calcium, magnesium, barium, strontium, niobium, and tantalum.