Lithium Rare-Earth Halide Solid Electrolyte Safety
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Solution Overview
Problem
Conventional lithium batteries using liquid electrolytes face safety concerns due to flammability and lithium dendrite formation, which can lead to short circuits and heat issues, necessitating the development of safer, more stable solid electrolytes with higher ionic conductivity and lower activation energy.
Innovation Solution
The development of new lithium rare-earth halides with the formula Li6-3x-4y RExTyX6, where X is a halogen, and RE denotes two or more different rare earth metals, which are synthesized through a process involving mechanical treatment and solvent removal, offering improved ionic conductivity, chemical, and mechanical stability, as well as cost-effectiveness and scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium batteries use liquid electrolytes, then high energy and power density is achieved, but safety concerns arise due to flammability and lithium dendrite formation
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid, fundamentally altering the safety parameters. Solid electrolytes eliminate flammability and suppress lithium dendrite formation while maintaining ionic conductivity, directly resolving the safety concerns associated with liquid electrolytes
Solution Approach 2:
The invention uses composite materials consisting of lithium rare-earth halides with specific compositions (Li6-3x-4yRExTyX6) that combine multiple rare-earth elements. This composite approach enhances both safety and ionic conductivity simultaneously, addressing the trade-off between safety and performance
2Reliability
If solid electrolytes are used to improve safety, then flammability and dendrite formation are suppressed, but ionic conductivity needs to be enhanced for next-generation batteries
Solution Approach 1:
The patent optimizes compositional parameters by incorporating specific ratios of rare-earth elements (x, y parameters in the formula) and halogen types to achieve the desired balance between safety and ionic conductivity. The controlled substitution of rare-earth elements allows tuning of both safety and conductive properties
Solution Approach 2:
The invention introduces local compositional variations by using different rare-earth elements at specific positions in the crystal structure. This local quality approach allows different regions of the electrolyte to contribute differently to safety and ionic conductivity, optimizing both properties simultaneously
3Strength
If Li3YCl6 materials are used as solid electrolytes, then mechanical stability is achieved, but ionic conductivity and activation energy need improvement
Solution Approach 1:
The patent modifies the compositional parameters of Li3YCl6 by incorporating additional rare-earth elements and adjusting the stoichiometry (x, y values). This parameter optimization maintains the mechanical stability of the Li3YCl6 structure while enhancing ionic conductivity and reducing activation energy through compositional tuning
Data Source
AI summary
The present invention concerns new lithium rare earth halides that may be used as solid electrolytes or in electrochemical devices. The invention also refers to wet and dry processes for the synthesis of such lithium rare earth halides and lithium rare earth halides susceptible to be obtained by these processes.