Oxide Solid Conductor Composition for Room-Temperature Lithium Transport
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Solution Overview
Problem
Lithium secondary batteries using liquid electrolytes face stability issues, particularly when exposed to water, and oxide-based solid electrolytes in all-solid-state batteries have low ionic conductivity at room temperature, necessitating the development of a solid conductor with improved ionic conductivity and stability.
Innovation Solution
A solid conductor comprising compounds like Li1+x+y-zTa2-xMxP1-yQyO8-zXz or Li1+x+y-zTa2-xMxP1-yQyO8·zLiX, where M is an element with an oxidation number of +4, Q is an element with an oxidation number of +4, and X is a halogen or pseudohalogen, is introduced, with specific compositions and heat-treatment processes to enhance ionic conductivity and lithium stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide-based solid electrolyte is used, then ionic conductivity is improved, but stability deteriorates due to toxic substance generation
Solution Approach 1:
The patent changes the chemical composition from sulfide-based to oxide-based solid electrolyte, fundamentally altering the material system to eliminate toxic substance generation while maintaining acceptable ionic conductivity through dopant optimization. This parameter change in base material composition addresses the harmful factor issue.
Solution Approach 2:
The patent converts the inherent limitation of oxide-based electrolytes (low ionic conductivity) into a benefit by using it as a stable, non-toxic base material, then compensates for the conductivity deficiency through controlled dopant addition, effectively transforming the material system to eliminate toxicity while maintaining performance.
2Quantity of substance
If liquid electrolyte is used in lithium secondary battery, then electrochemical capacity is improved, but stability deteriorates when exposed to water
Solution Approach 1:
The patent transitions the electrolyte from liquid phase to solid phase, fundamentally changing the physical state to eliminate water exposure instability while maintaining electrochemical functionality. This phase transition enables the battery to achieve both high capacity and improved stability.
Solution Approach 2:
The patent develops a composite solid electrolyte material combining multiple elements (Li, Ta, M, P, Q, O, X) in a structured oxide framework that provides both the electrochemical capacity needed for battery performance and the structural stability required for water resistance, replacing the liquid electrolyte system.
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 solid conductor achieves high ionic conductivity at room temperature and improved lithium stability, reducing internal resistance in electrochemical batteries and enhancing their performance and safety.
Implementation Method 1
the solid electrolyte provides high ionic conductivity and low electron conductivity
Implementation Method 2
heat-treating the precursor mixture in an oxidizing gas to manufacture a solid conductor
Data Source
AI summary
A solid conductor including:a compound represented by Formula 1, a compound represented by Formula 2,or a combination thereofLi1+x+y-zTa2-xMxP1-yQyO8-zXz Formula 1wherein, in Formula 1,M is an element having an oxidation number of +4,Q is an element having an oxidation number of +4,X is a halogen, a pseudohalogen, or a combination thereof, and0≤x≤2, 0≤y<1, and 0≤z≤2, except that cases i) x and y and z are simultaneously 0, ii) M is Hf, X is F, x is 1, y is 0, and z is 1, iii) M is Hf, X is Cl, x is 2, y is 0, and z is 2, and iv) M is Hf, X is F, x is 2, y is 0, and z is 2,Li1+x+y-zTa2-xMxP1-yQyO8·zLiX Formula 2wherein, in Formula 2,M is an element having an oxidation number of +4,Q is an element having an oxidation number of +4,X is a halogen, a pseudohalogen, or a combination thereof, and0≤x≤2, 0≤y<1, and 0≤z≤2, except that cases i) x and y and z are simultaneously 0, ii) M is Hf, X is F, x is 1, y is 0, and z is 1, iii) M is Hf, X is Cl, x is 2, y is 0, and z is 2, and iv) M is Hf, X is F, x is 2, y is 0, and z is 2.