Solid-State Electrolyte for Lithium Metal Battery Stability
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Solution Overview
Problem
Current solid-state lithium electrolytes have low lithium conductivity and are not stable in the presence of lithium metal, posing challenges for the development of safe and efficient lithium metal batteries.
Innovation Solution
A solid-state ion conductor comprising a compound of Formula Li(6-a)x+2y-b*z-6A1−xMaxOyXbz, where A is an element with an oxidation state of +6, M is an element with an oxidation state of +2, +3, +4, or +5, and X is an element with an oxidation state of -1 or -3, which provides improved ionic conductivity and stability when used in lithium batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid-state electrolytes are used, then the battery structure is simplified and safety is improved, but lithium conductivity is significantly reduced compared to liquid alternatives
Solution Approach 1:
The patent employs composite solid-state electrolyte materials combining multiple elements (Li, A, M, X) in specific ratios to achieve both high ionic conductivity and stability. The composite nature of the material allows simultaneous optimization of conductivity pathways while maintaining structural integrity for safety.
Solution Approach 2:
The patent systematically varies compositional parameters (x, y, z ratios of different elements) and thermal processing parameters (heating temperature, holding time) to optimize the electrolyte's ionic conductivity while maintaining stability with lithium metal anodes.
2Use of energy by moving object
If solid-state electrolytes with high ionic conductivity are used, then lithium metal stability is compromised, but if conventional electrolytes are used, then conductivity is insufficient
Solution Approach 1:
The patent optimizes the compositional parameters (stoichiometric ratios of Li, A, M, and X elements) to achieve a balance where ionic conductivity is maximized while chemical stability with lithium metal is maintained. Specific ranges of x, y, and z values are identified to resolve this contradiction.
Solution Approach 2:
The electrolyte material exhibits different local properties: high ionic conductivity in specific crystallographic directions or regions, while maintaining chemical stability in other regions or at interfaces with lithium metal, allowing both requirements to be satisfied simultaneously.
3Use of energy by moving object
If lithium metal is used as negative electrode to improve energy density, then specific energy and power density are improved, but stability to air and chemical stability are reduced
Solution Approach 1:
The solid-state electrolyte acts as an intermediary protective layer between the lithium metal anode and the external environment (air), preventing direct exposure and degradation of lithium metal while maintaining ionic conductivity for battery operation.
Solution Approach 2:
The electrolyte uses composite materials with specific compositional ranges that provide both high ionic conductivity for energy density and chemical stability for protection against air, resolving the contradiction between performance and stability.
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 proposed solid-state ion conductor achieves ionic conductivity of 1×10−7 S/cm at 23°C, stability with lithium metal, and reduced likelihood of short-circuits, enhancing the safety and performance of lithium metal batteries.
Implementation Method 1
the lithium conductivity of available solid-state electrolytes is significantly less than liquid alternatives
Data Source
AI summary
A solid-state ion conductor includes a compound of Formula 1:Li(6-a)x+2y-b*z-6A1−xMaxOyXbz Formula 1wherein, in Formula 1, A is an element having an oxidation state of +6, M is an element having an oxidation state of a, wherein a is +2, +3, +4, +5, or a combination thereof, X is an element having an oxidation state of b, wherein b is −1, −3, or a combination thereof, and 2<[(6−a)x+2y−b*z−6]≤6.5, 0≤x≤1, y>0, and z≥0.