Reactive Sintering of Ceramic Li-Ion Electrolytes for Hermetic Membranes
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Solution Overview
Problem
Conventional glass-ceramic processes for forming lithium-ion solid electrolyte membranes are limited by the requirement for stable glass formation, which restricts the achievement of dense, hermetic, and conductive membranes while being costly.
Innovation Solution
A reactive sintering method involving the combination of an amorphous, glassy, or low melting temperature solid reactant with a refractory oxide reactant, which are then cast and sintered to form a dense, hermetic Li-ion conductive ceramic electrolyte membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional glass-ceramic process is used to form hermetic membranes, then the membrane can be made dense and hermetic, but the conductivity and cost are compromised
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating lithium-containing glass or ceramic powders with specific Li2O content (40-70 wt%) and combining them with refractory oxide powders in controlled ratios. This compositional parameter change enables the formation of lithium-ion conductive phases during reactive sintering, achieving both hermeticity and conductivity simultaneously
Solution Approach 2:
The patent creates a composite material system by combining lithium-containing glass or ceramic powders with refractory oxide powders (such as TiO2, SiO2, Al2O3). This composite approach allows the final sintered product to exhibit both the hermeticity of glass-ceramic materials and the lithium-ion conductivity of lithium phosphate phases, resolving the contradiction between hermeticity and conductivity
2Reliability
If conventional glass-ceramic process is used, then hermetic membranes can be formed, but the processing cost increases
Solution Approach 1:
The patent reduces processing cost by changing the sintering temperature parameter from conventional high temperatures (>1000°C) to lower temperatures (700-900°C). This parameter change is achieved through the reactive sintering mechanism where in-situ formed lithium phosphate phases promote densification at lower temperatures, eliminating the need for expensive high-temperature equipment and reducing energy costs
3Ease of manufacture
If stable glass formation is required, then glass-ceramic process can proceed, but compositional flexibility is limited
Solution Approach 1:
The patent applies preliminary action by pre-synthesizing lithium-containing glass or ceramic powders with controlled composition and particle size (0.5-5 μm) before the reactive sintering process. This preliminary preparation ensures that the powders are ready to react and densify at lower temperatures without requiring stable glass formation during sintering, thereby enabling broader compositional flexibility while maintaining processability
Solution Approach 2:
The patent changes the fundamental parameter from requiring stable glass formation to utilizing reactive sintering of lithium-containing powders with refractory oxides. This parameter change in the process mechanism allows for wide compositional flexibility including various lithium phosphates (LATP, LAGP, LASnP) while maintaining ease of manufacture through controlled reactive sintering
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 method allows for the formation of dense, hermetic, and conductive lithium-ion electrolyte membranes without the limitations of stable glass formation, achieving lower processing temperatures and broader compositional flexibility, thus reducing costs and improving process control.
Implementation Method 1
A reactive sintering method involving the combination of an amorphous, glassy, or low melting temperature solid reactant with a refractory oxide reactant, which are then cast and sintered to form a dense, hermetic Li-ion conductive ceramic electrolyte membrane.
Data Source
AI summary
Solid lithium-ion ceramic electrolyte membranes have an average thickness of less than 200 micrometers. A constituent electrolyte material has an average grain size of less than 10 micrometers. The solid lithium-ion ceramic electrolyte is free-standing. Alternatively, solid lithium-ion electrolyte membranes have a composition represented by Li1+x−yMxM′2−x−yM″y(PO4)3, where M is a 3+ ion, M′ is a 4+ ion, M″ is a 5+ ion, 0≤x≤2 and 0≤y≤2.