Fluorinated Halide Cathode Material for High-Voltage Solid-State Batteries
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Solution Overview
Problem
Existing all-solid-state batteries face degradation in charge-discharge characteristics when operating at potentials higher than 4.3 V vs. Li/Li+, due to oxidative decomposition of halide solid electrolytes containing Cl, Br, or I, and low oxidation resistance of sulfide solid electrolytes, limiting their energy density and efficiency.
Innovation Solution
A positive electrode material comprising a halide solid electrolyte with F, which provides high oxidation resistance and ionic conductivity, allowing operation at potentials up to 6.0 V vs. Li/Li+, comprising Li, F, and at least one of Ti, Zr, or Al, with specific compositional ratios and structures to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halide solid electrolytes containing Cl, Br, or I are used, then ionic conductivity is improved, but oxidative decomposition occurs at potentials higher than 4.3 V vs. Li/Li+
Solution Approach 1:
The patent changes the chemical composition parameter of the halide solid electrolyte by specifically selecting fluorine-containing compounds (Li2MgF4, Li2CaF4, Li2BaF4, Li2SrF4, Li2ZnF4, Li2AlF6, Li2GaF6, Li2InF6) to achieve high oxidation resistance at potentials above 4.3 V vs. Li/Li+, resolving the contradiction between ionic conductivity and oxidation stability
Solution Approach 2:
The patent creates a composite positive electrode material combining fluorine-containing halide solid electrolyte with positive electrode active material, where the composite structure enables both high ionic conductivity and exceptional oxidation resistance, allowing operation at potentials up to 6.0 V vs. Li/Li+ without charge-discharge efficiency degradation
2Ease of manufacture
If sulfide solid electrolytes are used, then ease of manufacture is improved, but oxidation resistance is insufficient for high potential operation
Solution Approach 1:
The patent changes the electrolyte material parameter from sulfide-based to fluorine-containing halide-based solid electrolytes, maintaining manufacturability through similar processing techniques while achieving the required oxidation resistance for high-potential operation above 4.3 V vs. Li/Li+
3Quantity of substance
If operating potential is increased above 4.3 V vs. Li/Li+, then energy density is improved, but charge-discharge characteristics degrade due to electrolyte decomposition
Solution Approach 1:
The patent changes the operating potential parameter to greater than 4.3 V vs. Li/Li+ (up to 6.0 V) by introducing fluorine-containing halide solid electrolytes, which maintain exceptional charge-discharge characteristics even at these elevated potentials, thereby achieving high energy density without performance degradation
Solution Approach 2:
The composite structure of fluorine-containing halide solid electrolyte and positive electrode active material enables stable operation at high potentials, allowing the battery to achieve high energy density through increased operating voltage while maintaining excellent charge-discharge efficiency
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
Enables batteries to maintain excellent charge-discharge efficiency and increase energy density by operating at higher potentials, overcoming the limitations of previous electrolytes and achieving high power and energy storage capabilities.
Implementation Method 1
The halide solid electrolyte comprises F and has high ionic conductivity, allowing operation at potentials up to 6.0 V vs. Li/Li+
Implementation Method 2
The positive electrode active material is capable of occluding and releasing lithium ions at greater than 4.3 V versus lithium
Data Source
AI summary
A positive electrode material of the present disclosure comprises a positive electrode active material and a halide solid electrolyte. The halide solid electrolyte comprises F. The positive electrode active material is capable of occluding and releasing lithium ions at greater than 4.3 V versus lithium. A battery of the present disclosure comprises a positive electrode, a negative electrode, and an electrolyte layer disposed between the positive electrode and the negative electrode. The positive electrode comprises the positive electrode material of the present disclosure.