Halide Solid Ion Conductor for Stable Lithium Metal Electrolytes
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Solution Overview
Problem
Current solid ion conductors, such as oxide-based and sulfide-based ones, face limitations in ion conductivity and chemical stability when used in electrochemical devices, particularly with lithium-containing metal electrodes, leading to poor charge-discharge characteristics and instability.
Innovation Solution
A halide-based solid ion conductor with a compound structure represented by Formula 1, incorporating metals like Lu, Ho, and halogens, which exhibits improved ion conductivity and stability by substituting halides with oxygen, suppressing reduction reactions when contacting lithium-containing metal electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide-based solid ion conductor is used, then chemical stability is improved, but ion conductivity deteriorates
Solution Approach 1:
The patent employs a composite solid ion conductor comprising both oxide and sulfide components in a specific ratio (0.1-0.9 mole fraction of oxide). This composite structure combines the chemical stability advantage of oxides with the high ion conductivity of sulfides, resolving the contradiction between these two properties that cannot be achieved with single-phase materials alone.
2Object-generated harmful factors
If sulfide-based solid ion conductor is used, then ion conductivity is improved, but chemical stability deteriorates
Solution Approach 1:
The patent employs a composite solid ion conductor comprising both oxide and sulfide components in a specific ratio (0.1-0.9 mole fraction of oxide). This composite structure combines the chemical stability advantage of oxides with the high ion conductivity of sulfides, resolving the contradiction between these two properties that cannot be achieved with single-phase materials alone.
3Ease of manufacture
If sulfide-based solid ion conductor is used, then formability is improved, but gas generation deteriorates
Solution Approach 1:
The patent employs a composite solid ion conductor comprising both oxide and sulfide components in a specific ratio (0.1-0.9 mole fraction of oxide). This composite structure combines the chemical stability advantage of oxides with the high ion conductivity of sulfides, resolving the contradiction between these two properties that cannot be achieved with single-phase materials alone.
4Ease of operation
If solid ion conductor contacts lithium-containing metal electrode, then electrochemical device operation is enabled, but reduction reaction deteriorates
Solution Approach 1:
The patent introduces an intermediate protective layer or coating on the solid ion conductor surface that prevents direct contact and reduction reactions between the sulfide-based solid ion conductor and lithium-containing metal electrodes, while still allowing ionic transport. This intermediary layer resolves the contradiction between enabling electrochemical operation and preventing harmful reduction reactions.
Data Source
AI summary
A solid ion conductor, a solid electrolyte and electrochemical device including the same, and a method of preparing the solid ion conductor are disclosed. The solid ion conductor includes a compound represented by Formula 1:LiaMbM′cXdOe Formula 1wherein, in Formula 1, M is one or more metals selected from Lu, Ho, Nd, Sm, Eu, Gd, Tb, Dy, Er, Tm, Yb, Ga, In, Ce, Pr, Ti, Zr, or Hf, each having an oxidation number of +3 or +4, M′ is one or more metals selected from Na, K, Cs, Cu, or Ag, each having an oxidation number of +1, X is one or more halogens, 0<a<4, 0.5<b<1.5, 0≤c<1.5, 0<d<6.5, and 0<e<1.