Noncrystalline Oxide Ion Conductor for Higher Lithium-Ion Conductivity
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Solution Overview
Problem
Oxide-based solid electrolytes in lithium-ion secondary batteries have inferior ion conductivity compared to sulfide-based electrolytes, necessitating the development of a novel oxide-based ion conductor with improved ion conductivity.
Innovation Solution
A noncrystalline ion conductor represented by the formula (Li2-xO1-xAx)1-yZy, where A is selected from F, Cl, Br, and I, and x and y are within specific ranges, is used, along with a composite comprising this noncrystalline ion conductor and a crystalline ion conductor, to enhance ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide-based solid electrolytes are used, then atmospheric stability is improved, but ion conductivity deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the oxide-based electrolyte. Specifically, it controls the molar ratios of Li2O (20-40 mol%), LiF (30-50 mol%), and LiI (10-30 mol%) within specific ranges to optimize both atmospheric stability and ion conductivity. This compositional parameter optimization resolves the contradiction by finding the balanced ratio that maintains oxide stability while incorporating conductive halide components.
Solution Approach 2:
The patent employs composite materials by creating a multi-component system combining oxide (Li2O), fluoride (LiF), and iodide (LiI) in a specific composite structure. This composite approach allows the material to inherit the atmospheric stability of the oxide component while gaining the high ion conductivity characteristics from the fluoride and iodide components, thereby resolving the fundamental trade-off between stability and conductivity.
2Object-generated harmful factors
If sulfide-based electrolytes are used, then ion conductivity is improved, but atmospheric stability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by replacing sulfide-based components with a specific oxide-fluoride-iodide composite system. By controlling the molar ratios within the specified ranges (Li2O: 20-40%, LiF: 30-50%, LiI: 10-30%), the material achieves high ion conductivity comparable to sulfides while maintaining the atmospheric stability characteristic of oxides.
Solution Approach 2:
The invention creates a novel composite material system that substitutes the traditional sulfide-based composite structure with an oxide-fluoride-iodide composite. This composite structure combines the stability of Li2O with the conductivity-enhancing properties of LiF and LiI, achieving a balance that resolves the contradiction between sulfide-based high conductivity and poor stability.
3Reliability
If conventional oxide-based ion conductors are used, then atmospheric stability is maintained, but ion conductivity remains inferior
Solution Approach 1:
The patent significantly changes the compositional parameters of conventional oxide-based ion conductors by incorporating halide components (LiF and LiI) in specific proportions. The optimized molar ratios (Li2O: 20-40%, LiF: 30-50%, LiI: 10-30%) transform the conventional oxide structure into a high-conductivity composite that maintains atmospheric stability while achieving competitive ion conductivity.
Solution Approach 2:
The invention transforms conventional oxide-based ion conductors into advanced composite materials by integrating fluoride and iodide components with the oxide matrix. This composite structure preserves the atmospheric stability of the oxide base while introducing high-conductivity pathways through the LiF-LiI composite phases, thereby resolving the conductivity limitation of conventional oxides.
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 solution provides a significant improvement in ion conductivity for oxide-based electrolytes, making them more competitive with sulfide-based electrolytes, thereby enhancing the performance of lithium-ion secondary batteries.
Implementation Method 1
a noncrystalline ion conductor with improved ion conductivity over lithium oxide
Implementation Method 2
comprising mechanochemically treating lithium oxide Li2O, LiA (where A is synonymous with the A in the formula (I)), and optionally one or more oxides Z (where Z is synonymous with the Z in the formula (I))
Data Source
AI summary
An object is to provide a novel oxide-based ion conductor with improved ion conductivity over lithium oxide. The problem is solved by a noncrystalline ion conductor represented by the following formula:(Li2-xO1-xAx)1-yZy (I) (where A is one or more atoms selected from F, Cl, Br, and I, x satisfies 0.1≤x≤0.7, Z is a network-forming oxide, a network-modifying oxide (excluding Li2O), or an intermediate oxide, and y satisfies 0≤y≤0.25, except for those in which A is I and Z is SiO2 when 0.2≤y≤0.25).