Solid Electrolyte Screening via Crystallographic Filtering
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Solution Overview
Problem
Conventional secondary batteries using organic solvents are limited in achieving higher stability and energy density, while all-solid-state batteries with solid electrolytes offer safer alternatives, necessitating the development of solid electrolytes with excellent lithium ion conductivity and stability for enhanced battery capacity and efficiency.
Innovation Solution
A method involving the screening of solid electrolytes by extracting crystallographic information from databases, filtering compounds based on specific conditions such as mean square displacement and maximum framework displacement, and substituting elements to identify compounds with improved lithium ion conductivity and stability, including compounds like KLi4I5, RbLi4I5, and CsLi4Br5.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid electrolytes are developed to replace organic liquid electrolytes, then battery safety and energy density are improved, but lithium ion conductivity and stability must be maintained at high levels
Solution Approach 1:
The patent applies parameter changes by systematically varying the halogen element (X = Cl, Br, I) in the Li6-a-bPS5-cXc compound formula to optimize lithium ion conductivity while maintaining structural stability. By changing the halogen type and controlling composition ratios (a, b, c parameters), the patent achieves high ionic conductivity without sacrificing safety, thus resolving the contradiction between reliability improvement and conductivity maintenance.
2Quantity of substance
If conventional organic liquid electrolytes are used, then lithium ion conductivity is maintained, but battery safety and stability are limited
Solution Approach 1:
The patent employs phase transition principles by transitioning from organic liquid electrolyte phase to solid electrolyte phase. The solid electrolyte Li6-a-bPS5-cXc maintains ionic conductivity through solid-state ion transport mechanisms while providing inherent safety advantages of solid materials, thus resolving the contradiction between conductivity and safety by leveraging phase transition benefits.
3Quantity of substance
If solid electrolyte composition is optimized for high lithium ion conductivity, then battery capacity increases, but crystal structure stability may be compromised
Solution Approach 1:
The patent applies composite material principles by creating Li6-a-bPS5-cXc solid electrolytes that combine multiple elements (Li, P, S, and halogen X) in optimized ratios. This composite approach allows simultaneous optimization of lithium ion conductivity (for battery capacity) and crystal structure stability (through the stabilizing effect of halogen substitution), thus resolving the contradiction between capacity enhancement and structural 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
This approach enables the identification of solid electrolytes with high lithium ion conductivity and stability, maintaining crystal structure integrity and enhancing battery performance.
Implementation Method 1
The solid electrolyte conducts lithium ions in the electrode layer and/or the solid electrolyte layer
Implementation Method 2
screening a second group comprising compounds satisfying Condition 1 below among the first group... Compound in which a mean square displacement of a specific element is 30 Å2 or greater
Implementation Method 3
screening compounds satisfying Condition 2 below among the third group... Compound in which a maximum framework displacement of an element in a unit cell is less than 50 Å
Data Source
AI summary
Disclosed is a method of screening a solid electrolyte having excellent lithium ion conductivity and stability.