Halide Solid Ion Conductor Composition for Stable Li-Metal Electrolytes
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Solution Overview
Problem
Current solid electrolytes in all-solid lithium batteries lack sufficient stability towards lithium metal and have lower lithium ion conductivity compared to liquid substitutes, necessitating an improved solid electrolyte material.
Innovation Solution
A novel solid ion conductor compound with a specific composition, represented by Formula 1, is developed, which includes alkali metals, divalent to hexavalent metals, halogens, and trivalent anions, enhancing lithium ion conductivity and stability. The compound is prepared through a method involving a mixture of halide compounds treated in a solid phase, specifically using ball milling in an inert atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid electrolyte materials are used, then the battery structure is stable without combustible organic solvents, but the lithium ion conductivity is lower than liquid substitutes
Solution Approach 1:
The patent employs composite materials by combining multiple elements (Li, Na, M', X, Z) in a specific formula structure M3+m+(l-1)o+2p(M'k+lXnZp). This composite approach allows the solid electrolyte to achieve both high lithium ion conductivity and chemical stability simultaneously, resolving the contradiction between using stable solid materials and maintaining high ion conductivity.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the stoichiometric ratios and oxidation states of constituent elements in the solid electrolyte compound. By varying parameters such as the valence states (m, l, n, p) and elemental compositions, the material achieves optimized lithium ion conductivity while maintaining structural stability, overcoming the limitation of conventional solid electrolytes.
2Reliability
If conventional solid electrolyte materials are used, then the battery avoids combustible organic solvents, but the stability towards lithium metal is insufficient
Solution Approach 1:
The patent applies local quality by creating specific local chemical environments within the solid electrolyte structure. The unique combination of elements and their arrangements in the formula M3+m+(l-1)o+2p(M'k+lXnZp) create localized regions with optimized properties that enhance stability towards lithium metal while maintaining overall material stability.
Solution Approach 2:
The patent uses intermediary elements (M', X, Z) that act as mediators between lithium metal and the electrolyte structure. These intermediary components facilitate stable interactions with lithium metal, preventing unwanted reactions while enabling efficient ion transport, thus resolving the stability contradiction.
3Object-generated harmful factors
If a novel composition is designed to improve lithium ion conductivity, then ion conductivity increases, but the complexity of the compound increases
Solution Approach 1:
The patent achieves universality by designing a multi-functional compound structure where a single formula M3+m+(l-1)o+2p(M'k+lXnZp) simultaneously provides high lithium ion conductivity, stability towards lithium metal, and structural integrity. This universal structure eliminates the need for multiple separate components, reducing overall system complexity while maintaining enhanced 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 solid ion conductor compound achieves improved lithium ion conductivity and stability, maintaining discharge capacity at 93% or greater for 20 cycles and exhibiting increased lattice constants, thereby enhancing the performance of all-solid lithium batteries.
Implementation Method 1
the solid ion conductor compound has an ion conductivity of about 0.3 millisiemens per centimeter or greater at a temperature of about 25 °C
Implementation Method 2
treating the mixture in a solid phase to prepare the solid ion conductor compound, specifically using ball milling in an inert atmosphere
Implementation Method 3
The solid ion conductor compound has diffraction peaks at diffraction angles of 16°2θ±0.5°2θ, 20°2θ±0.5°2θ, 30°2θ±0.5°2θ, 32°2θ±0.5°2θ, 42°2θ±0.5°2θ, and 50°2θ±0.5°2θ, when analyzed by an X-ray diffraction using CuKα radiation
Data Source
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AI summary
A solid ion conductor compound including a compound represented by Formula 1: Formula 1 M3+m+(l-1)o+2p(M'k+)nX3+m+kn-lo-3p+qTl-oZ3'p wherein, in Formula 1, M is at least one alkali metal, M' is at least one of a divalent metal, a trivalent metal, a tetravalent metal, a pentavalent metal, a hexavalent metal, or a combination thereof, X is at least one halogen, T is at least one of a monovalent anion or a divalent anion, Z is at least one of a trivalent anion, 2≤k≤6, 1≤l≤2, -3≤m≤3, 0<n≤1, 0≤o<3, 0<p<2, -3≤q≤3, and 0<(3+m+kn-lo-3p+q).