Solid Ion Conductor Composition for Stable High-Conductivity Cells
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Solution Overview
Problem
Current solid electrolytes in all-solid lithium batteries lack sufficient stability towards lithium metal and exhibit lower lithium ion conductivity compared to liquid substitutes, necessitating an improved solid ion conductor compound.
Innovation Solution
A novel solid ion conductor compound with a specific composition, represented by Formula 1, is developed, comprising alkali metals, divalent to hexavalent metals, halogens, and trivalent anions, which is synthesized through a solid-phase treatment method, such as ball milling, to enhance lithium ion conductivity and stability.
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 uses composite materials by combining multiple elements (Li, Na, K, Rb, or Cs as M; divalent to hexavalent metals as M′; halogens as X; and trivalent anions as Z) in specific ratios to create a solid ion conductor compound that achieves both high stability and high lithium ion conductivity, resolving the contradiction between using stable solid electrolytes and maintaining good ion conductivity
Solution Approach 2:
The patent changes the chemical composition parameters of the solid electrolyte by defining specific ranges for stoichiometric ratios (0.01≤x≤0.30 for M content, 0.65≤y≤0.95 for M′ content, 0.05≤z≤0.35 for halogen content) to optimize both stability and lithium ion conductivity simultaneously
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 creates a composite solid ion conductor compound incorporating trivalent anions (such as PO4³⁻, (C6H5O7)³⁻, [Fe(CN)]³⁻, [Ag(S2O3)2]³⁻, N3⁻, or P3⁻) combined with alkali metals and divalent to hexavalent metals, which provides both structural stability and enhanced stability towards lithium metal through the synergistic effects of the composite composition
Solution Approach 2:
The patent applies local quality by introducing specific functional components (trivalent anions) into specific positions within the crystal structure, where these components locally enhance the stability towards lithium metal while maintaining overall structural integrity
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 ion conductor compound demonstrates improved lithium ion conductivity and stability, maintaining a discharge capacity of 93% or greater for 20 cycles and increased lattice constants, leading to enhanced performance in all-solid secondary batteries.
Implementation Method 1
the lithium ion conductivity of solid electrolytes in the related art is lower than that of liquid substitutes
Implementation Method 2
treating the mixture in a solid phase to prepare the solid ion conductor compound
Data Source
AI summary
A solid ion conductor compound including a compound represented by Formula 1:M3+m+(l−1)o+2p(M′k+)nX3+m+kn−lo−3p+qTl−oZ3−p Formula 1wherein, 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).