Gel Polymer Electrolyte Composition for Lithium Secondary Battery
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Solution Overview
Problem
Lithium secondary batteries face challenges with the use of liquid electrolyte solutions due to high volatility and low safety, particularly at high temperatures, leading to combustion and thermal runaway, while gel polymer electrolytes have lower ionic conductivity and inadequate flame retardancy.
Innovation Solution
A gel polymer electrolyte composition for lithium secondary batteries is developed, incorporating a lithium salt, non-aqueous organic solvent, ionic liquid, oligomer, and heat stabilizer, which improves thermal stability and flame retardancy by enhancing the polymer network structure and oxidation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If liquid electrolyte solution is used to increase energy density and operating voltage, then battery capacity and power are improved, but safety deteriorates due to high volatility and combustion risk at high temperatures
Solution Approach 1:
The patent employs gel polymer electrolyte which represents a phase transition from liquid to gel state. This gel structure maintains the ionic conductivity benefits of liquid electrolytes while eliminating volatility and combustion risks, directly resolving the safety issue at high temperatures while preserving energy density
Solution Approach 2:
The patent uses composite gel polymer electrolyte comprising multiple components including polymer matrix, ionic liquid, and various additives. This composite structure combines the advantages of different materials to achieve both high energy density and improved safety, preventing combustion while maintaining electrochemical performance
2Use of energy by moving object
If high voltage of 4.3 V or more is applied to increase energy density, then battery power is improved, but electrolyte decomposition occurs forming unstable film on positive electrode
Solution Approach 1:
The patent employs film-forming additives in the gel polymer electrolyte that pre-form stable protective films on the positive electrode surface before high-voltage operation begins. This preliminary action prevents subsequent electrolyte decomposition and maintains electrolyte stability during high-voltage charging, enabling safe operation at 4.3 V or higher
Solution Approach 2:
The patent controls the formation of protective films on the electrode surface, converting the potentially harmful decomposition products into beneficial stable surface layers. These films, initially formed through controlled decomposition, actually protect the electrolyte from further decomposition at high voltages, turning a harmful process into a protective mechanism
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 composition achieves improved high-temperature stability and flame retardancy, reducing the risk of thermal runaway and maintaining ionic conductivity, thereby enhancing the safety and performance of lithium secondary batteries.
Implementation Method 1
a gel polymer electrolyte having improved flame retardancy as well as oxidation resistance
Implementation Method 2
improves thermal stability and flame retardancy by enhancing the polymer network structure and oxidation resistance
Implementation Method 3
improves thermal stability and flame retardancy by enhancing the polymer network structure and oxidation resistance
Data Source
AI summary
The present invention relates to a gel polymer electrolyte composition for a lithium secondary battery and a secondary battery including the same, and particularly, to a gel polymer electrolyte composition for a lithium secondary battery, which includes a lithium salt, a non-aqueous organic solvent, an ionic liquid, an oligomer having a specific structure, a heat stabilizer, and a polymerization initiator, and a lithium secondary battery in which high-temperature stability is improved by including the same.