Thermosetting Gel Polymer Electrolyte for Stable Battery Wetting
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Solution Overview
Problem
The existing liquid electrolytes in lithium secondary batteries suffer from low stability, leading to increased battery thickness, potential explosion due to gas generation, and uneven electrode reaction, necessitating the development of a more stable gel polymer electrolyte that prevents pre-gelation and improves wetting during battery preparation.
Innovation Solution
A thermosetting electrolyte composition for lithium secondary batteries, comprising LiPF6, a second lithium salt, a non-aqueous organic solvent, and a polymer or oligomer with a thermopolymerizable functional group, which undergoes thermal polymerization to form a gel polymer electrolyte without a polymerization initiator, preventing pre-gelation and enhancing adhesion and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymerization initiator is used to form gel polymer electrolyte, then gelation can be achieved, but pre-gelation occurs at room temperature causing reduced wetting and increased interfacial resistance
Solution Approach 1:
The patent removes the polymerization initiator from the electrolyte composition, extracting the harmful element that causes pre-gelation. The gelation is achieved through thermal polymerization of vinylene carbonate at elevated temperatures without requiring a polymerization initiator, thus preventing pre-gelation at room temperature while maintaining gelation stability.
Solution Approach 2:
The patent changes the polymerization activation parameter from chemical (polymerization initiator) to thermal (temperature). By using thermal polymerization of vinylene carbonate at temperatures above its polymerization point, the system achieves gelation only when needed during battery formation, preventing premature gelation while ensuring complete gelation when heated.
2Reliability
If liquid electrolyte is used, then ion conductivity is maintained, but stability is low leading to gas generation and battery swelling
Solution Approach 1:
The patent creates a composite gel polymer electrolyte system combining polyvinylidene fluoride polymer matrix with vinylene carbonate gel-forming component. This composite structure provides both the mechanical stability and adhesion of polymer materials while maintaining the ion conductivity of liquid electrolytes, preventing gas generation through superior electrochemical stability.
Solution Approach 2:
The patent utilizes the phase transition of vinylene carbonate from liquid to gel state through thermal polymerization. This phase transition transforms the electrolyte from a liquid state prone to gas generation to a gel state with enhanced stability, while the gel structure maintains sufficient ion conductivity for battery operation.
3Strength
If gel polymer electrolyte is formed by coating method, then adhesion is improved, but injection into battery is complex
Solution Approach 1:
The patent merges the electrolyte filling process with the gelation process by injecting the liquid electrolyte composition into the battery first, then inducing gelation in-situ through heating. This combines the simplicity of liquid injection with the adhesion benefits of gel polymer electrolyte, eliminating the need for separate coating steps while maintaining strong adhesion to electrodes and separator.
Solution Approach 2:
The patent uses thermal energy as an intermediary to trigger gelation after injection. By using temperature as the activating medium rather than chemical initiators, the system achieves gelation in-situ within the battery structure, simplifying the manufacturing process while ensuring uniform gel formation and maintaining adhesion properties.
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 solution provides improved impregnability, oxidation stability, and capacity characteristics for lithium secondary batteries by forming a stable gel polymer electrolyte that maintains mechanical strength and prevents thermal runaway, even at high temperatures.
Implementation Method 1
a polymer or oligomer with a thermopolymerizable functional group, which undergoes thermal polymerization to form a gel polymer electrolyte
Implementation Method 2
an ion conductive organic liquid electrolyte, in which a salt is dissolved in an organic solvent using a carbonate organic solvent as a main solvent
Data Source
AI summary
The present invention relates to a thermosetting electrolyte composition for a lithium secondary battery, a gel polymer electrolyte prepared therefrom, and a lithium secondary battery including the gel polymer electrolyte, and particularly, to a thermosetting electrolyte composition for a lithium secondary battery, which includes LiPF6 as a first lithium salt, a second lithium salt excluding the LiPF6, a non-aqueous organic solvent, and a polymer or oligomer containing a unit represented by Formula 1, a gel polymer electrolyte prepared therefrom, and a lithium secondary battery including the gel polymer electrolyte.