Lithium-Ion Ceramic Electrolyte Phase Purity and Conductivity
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Solution Overview
Problem
Current lithium-ion conducting ceramic materials face issues such as poor ion conductivity at room temperature, porosity leading to leakage, and phase impurity, which can result in cracking and reduced utility in electrochemical cells like batteries.
Innovation Solution
Development of lithium-ion-conductive ceramic materials with specific general formulas (e.g., MI1+x+z−δMIIIxMIVayMIVb2−x−yMVzP3−zO12) and processing methods involving calcination, milling with mixed media, and sintering to achieve high phase purity and low porosity, enabling selective lithium ion transport while preventing other ions from passing through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dense ceramic membranes are used as electrolyte, then faradaic efficiency is improved (close to 100 percent), but ion conductivity at room temperature deteriorates (relatively poor)
Solution Approach 1:
The patent modifies the chemical composition parameters of the ceramic material by incorporating specific ratios of lithium oxide, aluminum oxide, titanium dioxide, and phosphorus pentoxide to create a composite ceramic electrolyte that achieves both high density and room temperature ion conductivity
Solution Approach 2:
The patent creates a composite ceramic material combining multiple oxides (Li2O-Al2O3-TiO2-P2O5 system) to achieve properties that individual components cannot provide alone, resulting in both high density for faradaic efficiency and enhanced ion conductivity at room temperature
2Reliability
If ceramic materials are made dense to prevent leakage, then porosity is reduced (preventing undesired leakage), but ion conductivity deteriorates (relatively poor at room temperature)
Solution Approach 1:
The patent optimizes the chemical composition parameters within the Li2O-Al2O3-TiO2-P2O5 system to create a dense ceramic structure that maintains high ion conductivity through specific stoichiometric ratios and phase composition control
Solution Approach 2:
The patent utilizes phase transformation during sintering to achieve a dense microstructure with appropriate porosity, transforming the ceramic from a porous precursor state to a dense final state that prevents leakage while maintaining ion conductivity pathways
3Manufacturing precision
If ceramic materials are processed to achieve high density, then phase purity deteriorates (relatively poor phase purity), but porosity is improved (lower porosity)
Solution Approach 1:
The patent performs preliminary calcination and phase formation treatments before final sintering to ensure complete reaction and phase development, preventing impurity formation during the densification process
Solution Approach 2:
The patent employs a continuous multi-stage processing sequence (mixing, calcination, sintering, cooling) that maintains proper atmospheric conditions and temperature profiles throughout to prevent phase segregation and ensure uniform phase purity in the final dense product
4Strength
If ceramic materials are made with high density, then mechanical strength is improved (reduced cracking), but ion conductivity deteriorates (relatively poor at room temperature)
Solution Approach 1:
The patent modifies compositional parameters to create a ceramic with optimized grain structure and phase distribution that provides both mechanical strength and ion conductivity pathways, using specific oxide ratios in the Li2O-Al2O3-TiO2-P2O5 system
Solution Approach 2:
The patent creates a composite ceramic structure where the multi-oxide composition provides both mechanical reinforcement to prevent cracking and conductive pathways for lithium ion transport at room temperature
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 resulting materials exhibit high phase purity, low porosity, and enhanced lithium ion conductivity, making them suitable for various electrochemical applications with improved stability and performance.
Implementation Method 1
LiSICON (Lithium SuperIonic CONductor) is one type of ceramic material that is selective to lithium ions (i.e., conducts only lithium ions)
Data Source
AI summary
Lithium-ion-conducting ceramic materials are disclosed having characteristics of high lithium-ion conductivity at low temperatures, good current efficiency, and stability in water and corrosive media under static and electrochemical conditions. Some general formulas for the lithium-ion-conducting materials include MI1+x+z−δMIIIxMIVayMIVb2−x−yMVzP3−zO12 and MI1+x+4z−δMIIIxMIVayMIVb2−x−y−zP3O12, wherein MI comprises Li, Na, or mixtures thereof; 0.05<x<0.5, 0.05<y<2, 0≦z<3, and 0≦δ<0.5; MIII comprises Al, Hf, Sc, Y, La, or mixtures thereof; MIVa comprises Zr, Ge, Sn, or mixtures thereof; MIVb comprises Ti; and MV comprises Si, Ge, Sn, or mixtures thereof. In some cases, the lithium-ion conducting materials are formed through a process in which the materials' powdered precursors are milled after being calcined and before being sintered. The milling process may include using milling media of multiple sizes.