Halide Glass-Ceramic Solid Electrolyte for Uniform Cathode Interfaces
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Solution Overview
Problem
Solid secondary batteries face challenges with sulfide solid electrolytes due to toxicity and manufacturing difficulties, and oxide-based solid electrolytes have issues with uniform interfacial adhesion and high-temperature sintering processes that complicate battery structure formation.
Innovation Solution
A halogen compound-based solid electrolyte with a glass or glass-ceramic structure, comprising gallium, fluorine, and other halogens, is developed, offering improved formability and uniformity with the cathode without the need for high-pressure manufacturing or high-temperature sintering, and maintaining high ionic conductivity even with low water content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide solid electrolyte is used, then high ionic conductivity is achieved, but toxicity and manufacturing difficulty increase
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating halogen elements (F, Cl, Br, I) into the solid electrolyte structure, specifically using compounds like LiGaF4, LiAlF4, and their mixtures with Li2SiO3. This compositional parameter change maintains high ionic conductivity while eliminating the toxicity associated with sulfide-based electrolytes.
Solution Approach 2:
The patent employs composite material design by combining halogen-containing compounds (LiGaF4, LiAlF4) with lithium silicate (Li2SiO3) in specific ratios. This composite structure achieves both high ionic conductivity and improved air stability, resolving the contradiction between performance and safety.
2Stability of the object's composition
If oxide-based solid electrolyte is used, then air stability is improved, but interfacial adhesion uniformity deteriorates
Solution Approach 1:
The patent modifies the physical and chemical parameters of the solid electrolyte by incorporating halogen-containing compounds that exhibit glass-forming tendencies. This parameter change enables the material to form uniform interfaces with electrodes at lower temperatures, improving interfacial adhesion uniformity while maintaining air stability.
Solution Approach 2:
The patent creates local quality variations at the interface between the solid electrolyte and electrodes by controlling the composition and structure of the halogen-containing compound layers. This allows for optimized local interfacial properties that enhance adhesion uniformity without compromising the bulk air stability of the oxide-based electrolyte.
3Ease of manufacture
If high-pressure manufacturing is used, then sulfide solid electrolyte formability is improved, but device complexity increases
Solution Approach 1:
The patent changes the material parameters by developing halogen-containing solid electrolytes with inherent glass-forming capabilities and improved sinterability. This allows the material to be processed at lower pressures and temperatures, eliminating the need for complex high-pressure manufacturing equipment and simplifying the overall device fabrication process.
4Stability of the object's composition
If high-temperature sintering is used, then oxide-based solid electrolyte density is improved, but manufacturing complexity increases
Solution Approach 1:
The patent modifies the sintering parameters by utilizing halogen-containing compounds that enable low-temperature sintering. The presence of elements like F, Cl, Br, or I facilitates grain growth and densification at reduced temperatures, eliminating the need for complex high-temperature sintering processes while achieving adequate density for optimal performance.
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 new solid electrolyte enhances the safety and manufacturability of solid secondary batteries by providing improved interfacial uniformity and conductivity, reducing the risk of toxicity and simplifying the manufacturing process while maintaining performance across a range of temperatures.
Implementation Method 1
high ionic conductivity is desired... Anionic framework capable of conducting lithium ions
Implementation Method 2
glass transition temperature of -30°C or lower and a glass transition phenomenon... glass or glass-ceramic structure
Data Source
Figure 1
Figure 2~3A
Figure 3B~3C
AI summary
Provided are a solid electrolyte including a compound represented by Formula 1 or 3, the compound having a glass transition temperature of -30 °C or less, and a glass or glass-ceramic structure, a method of preparing the same, and an electrochemical device including the same. Formula 1 AQX-Ga1-zMz1(F1-kClk)3-3zZ3z1 wherein, in Formula 1, Q is Li or a combination of Li and Na, K, or a combination thereof, M is a trivalent cation, or a combination thereof, X is a halogen other than F, pseudohalogen, OH, or a combination thereof, Z is a monovalent anion, or a combination thereof, 1<A<5, 0≤z<1, 0≤z1≤1. and 0≤k1, Formula 3 AQX-aMz1Z3z1-bGa1-z(F1-kClk)3-3z wherein, in Formula 3, Q is Li or a combination of Li and Na, K, or a combination thereof; M is a trivalent cation, or a combination thereof, X is a halogen other than F, pseudohalogen, OH, or a combination thereof, Z is a monovalent anion, or a combination thereof, 0<a≤1, 0<b≤1, 0<a+b, a+b=4-A, 1<A<5, 0≤z<1, 0≤z1≤1, and 0≤k<1.