Cyclic Ester Electrolyte for High-Temperature Lithium Battery Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face safety issues due to side reactions between the negative electrode and electrolyte at high temperatures, leading to heat generation and potential deterioration.
Innovation Solution
An electrolyte composition for lithium secondary batteries comprising a lithium salt, an electrolyte additive, and a non-aqueous organic solvent, with a cyclic ester-based solvent as a main component, forms a solid electrolyte interface layer with high lithium ion conductivity and excellent heat resistance, reducing reactivity and suppressing side reactions at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional electrolyte compositions are used, then the battery can operate at high temperatures, but side reactions occur between the negative electrode and electrolyte leading to heat generation and safety issues
Solution Approach 1:
The patent introduces a mediator substance (specifically, a cyclic carboxylate compound) that acts as an intermediary between the negative electrode and the electrolyte. This mediator forms a protective interface layer that prevents direct contact and harmful side reactions between the electrode and electrolyte, while still allowing ionic conduction. The mediator substance specifically binds to the electrode surface, creating a barrier that suppresses exothermic reactions at high temperatures.
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by incorporating specific cyclic carboxylate compounds (such as lithium acetate, lithium propionate, etc.) at controlled concentrations (0.1-5 wt%). This parameter change modifies the interfacial chemistry between the electrode and electrolyte, altering the reaction kinetics and thermodynamics to suppress harmful side reactions while maintaining ionic conductivity.
2Adaptability or versatility
If the battery is exposed to high temperatures, then the battery can function in various environments, but the reactivity between negative electrode and electrolyte increases causing deterioration
Solution Approach 1:
The patent applies preliminary action by pre-forming a protective interface layer on the negative electrode surface before the battery undergoes high-temperature exposure. The cyclic carboxylate compound is introduced into the electrolyte system in advance, where it preferentially adsorbs onto the electrode surface during initial cycles or activation, creating a stable protective layer that prevents subsequent thermal degradation and side reactions during high-temperature operation.
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 electrolyte composition enhances the high-temperature safety of lithium secondary batteries by increasing the heat generation onset temperature and minimizing side reactions, thereby improving the battery's thermal stability and cycle characteristics.
Implementation Method 1
forms a solid electrolyte interface layer with high lithium ion conductivity and excellent heat resistance
Implementation Method 2
high lithium ion conductivity
Data Source
AI summary
An electrolyte composition for a lithium secondary battery according to an aspect of the present disclosure includes a lithium salt, an electrolyte additive, and a non-aqueous organic solvent. The electrolyte additive includes an inorganic compound, the non-aqueous organic solvent includes a cyclic ester-based solvent in an amount of about 60 vol % or more and less than 100 vol %, and the electrolyte composition exhibits a heat flow of about 30.0 W/g or less within a range of about 250° C. to 350° C. when the heat flow measurement is performed on a mixture containing a negative electrode active material of a 100% charged lithium secondary battery and the electrolyte composition, at a weight ratio of about 1:0.5.