Solid Electrolyte Composition for Room-Temperature Lithium-Ion Transport
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Solution Overview
Problem
Existing solid polymer electrolytes, such as polyethylene oxide (PEO), suffer from low ion conductivity at room temperature and are limited by high crystallinity, leading to poor lithium ion dissociation and difficulty in applying them to lithium secondary batteries, while sulfide-based electrolytes face stability issues due to impurity reactions and oxide-based electrolytes have lower conductivity and require high-temperature processing.
Innovation Solution
A compound with a specific structure, represented by Formula 1, and its lithium salt, are used to form a solid electrolyte that enhances ion conductivity and suppresses lithium dendrite formation by chelating to lithium ions, improving the performance and stability of all-solid-state batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If linear PEO polymer electrolyte is used, then the electrolyte structure is simple and easy to manufacture, but the ion conductivity at room temperature is very low due to high crystallinity and limited chain fluidity
Solution Approach 1:
The patent uses a copolymer structure combining PEO units with other polymer units (such as polypropylene carbonate or polyethylene carbonate) to create a composite material that maintains processability while reducing crystallinity and enhancing ion conductivity through synergistic effects of different polymer segments
Solution Approach 2:
The patent modifies the chemical structure parameters of the polymer electrolyte by introducing different repeating units with varying side chain lengths, functional groups, and molecular weights to optimize the balance between crystallinity, chain fluidity, and lithium ion dissociation at room temperature
2Reliability
If sulfide-based electrolyte is used, then the ion conductivity is high and interface resistance is low, but stability is poor due to reactions with moisture and impurities generating hydrogen sulfide
Solution Approach 1:
The patent develops composite electrolyte systems combining sulfide-based components with protective additives, coating layers, or hybrid polymer matrices that maintain the high ion conductivity of sulfides while providing a stable interface that prevents moisture-induced decomposition and hydrogen sulfide generation
Solution Approach 2:
The patent introduces intermediary protective layers or stabilizing additives that act as buffers between the sulfide-based electrolyte and moisture/impurities, preventing direct harmful reactions while allowing lithium ion transport to proceed efficiently
3Stability of the object's composition
If oxide-based electrolyte is used, then the chemical stability is high, but the ion conductivity is lower than sulfide-based electrolyte and high-temperature sintering is required
Solution Approach 1:
The patent modifies oxide-based electrolyte composition by adjusting stoichiometry, doping with alkali metals or other oxides, and controlling particle size and sintering conditions to enhance ion conductivity while maintaining the inherent chemical stability of oxide materials at lower processing temperatures
4Stability of the object's composition
If solid polymer electrolyte is used, then the chemical and electrochemical stability is high and leakage problems are solved, but the ion conductivity at room temperature is lower than liquid electrolyte
Solution Approach 1:
The patent creates composite solid polymer electrolytes by combining PEO-based polymers with ceramic fillers, plasticizers, or crosslinked networks that provide additional ion conduction pathways while maintaining the solid-state structure and electrochemical stability
Solution Approach 2:
The patent introduces porous structures or amorphous regions within the solid polymer electrolyte matrix that increase free volume and create channels for enhanced lithium ion transport at room temperature without compromising the overall structural integrity 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 compound increases ion conductivity and transference number, suppresses lithium dendrite growth, and enables fast charging capabilities in all-solid-state batteries, enhancing their performance and stability.
Implementation Method 1
A compound with a specific structure, represented by Formula 1, and its lithium salt, are used to form a solid electrolyte that enhances ion conductivity and suppresses lithium dendrite formation by chelating to lithium ions
Implementation Method 2
The polymer electrolyte is largely classified into a gel type and a solid type. The gel-type polymer electrolyte is an electrolyte which exhibits conductivity by impregnating a liquid electrolyte having a high boiling point in a polymer film and fixing the same together with a lithium salt
Data Source
AI summary
The present invention aims to improve upon conventional low lithium ion conductivity and resolve the performance and safety issues of an all-solid-state battery, and relates to a compound comprising a repeating unit represented by chemical formula 1 described in the present specification or a compound which is a lithium salt thereof, a composite comprising the compound and a lithium compound, and a solid electrolyte and an all-solid-state battery comprising same.