Cyclic Sulfonic Acid Ester Electrolyte for High-Temp Battery Stability
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Solution Overview
Problem
Existing non-aqueous electrolyte solutions for lithium ion secondary batteries suffer from degradation in battery characteristics at high temperatures due to solvent decomposition, leading to increased resistance and swelling, which current additives like benzenesulfonic acid ester derivatives and dioxadithiepin tetraoxide derivatives are insufficient in addressing.
Innovation Solution
A non-aqueous electrolyte solution containing a cyclic sulfonic acid ester compound with a specific structure, represented by general formula (1), which forms a protective coating (SEI) on electrode surfaces during initial charging, preventing further solvent degradation and improving battery stability and cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional non-aqueous electrolyte solutions are used, then the battery can operate at high temperature, but the solvent undergoes decomposition leading to increased resistance and gas generation
Solution Approach 1:
The patent applies preliminary action by introducing a protective film-forming additive that proactively forms a stable coating on the electrode surface before significant solvent decomposition occurs. This additive undergoes controlled decomposition during initial charging cycles to create a protective layer that prevents subsequent harmful reactions between the solvent and electrode at high temperatures, thereby maintaining battery characteristics.
Solution Approach 2:
The patent uses an intermediary substance (protective film-forming additive) that mediates between the solvent and the electrode surface. This additive forms an intermediate protective layer that acts as a barrier, preventing direct contact and harmful reactions between the solvent and electrode while still allowing lithium ion transport, thus resolving the contradiction between high temperature operation and battery reliability.
2Stability of the object's composition
If the solvent undergoes reductive decomposition on the negative electrode surface, then the decomposition product deposits on the electrode surface, but this causes increased resistance and battery swelling
Solution Approach 1:
The patent converts the harmful decomposition process into a beneficial one by selecting an additive that decomposes preferentially to form a protective layer. The additive's decomposition, which would normally be harmful, is instead utilized to create a stable coating that prevents further decomposition of the main electrolyte solvent, thus converting a harmful process into a protective mechanism.
Solution Approach 2:
The protective film-forming additive serves as an intermediary that prevents direct decomposition of the electrolyte solvent. It forms a stable intermediate layer on the electrode surface that blocks the formation of harmful decomposition products from the main solvent, while the additive itself decomposes in a controlled manner to create this protective barrier.
3Reliability
If existing additives like benzenesulfonic acid ester derivatives are used, then some protection is provided, but they are insufficient in suppressing solvent decomposition under high temperature conditions
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of the protective film-forming additive to achieve superior performance under high temperature conditions. The additive is designed with specific molecular characteristics that enhance its ability to form stable protective films at elevated temperatures, improving upon conventional additives like benzenesulfonic acid ester derivatives through controlled changes in chemical parameters.
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 cyclic sulfonic acid ester compound enhances battery characteristics by forming a protective coating that suppresses solvent decomposition, maintaining long-term reliability and stability, even at high temperatures, resulting in improved cycle life and capacity retention.
Implementation Method 1
the solvent in the electrolyte solution undergoes a reductive decomposition on a surface of the negative electrode
Implementation Method 2
the decomposition product forms a protective coating, i.e. SEI (Solid Electrolyte Interface), having a protection function
Implementation Method 3
the protective coating thus formed suppresses properly a chemical reaction or decomposition of the solvent at the electrode surface
Implementation Method 4
on a surface of the positive electrode, the solvent undergoes oxidative decomposition
Data Source
AI summary
The present invention relates to a non-aqueous electrolyte solution characterized by containing at least one type of cyclic sulfonic acid ester compound represented by general formula (1). According to the present invention, a non-aqueous electrolyte solution capable of improving battery characteristics can be provided.(In the formula, R1 to R4 are each independently a hydrogen atom, a fluorine atom, an alkyl group having 1-6 carbon atoms or an alkoxy group having 1-6 carbon atoms, and Z is a substituted or unsubstituted alkylene group having 1-6 carbon atoms, a substituted or unsubstituted fluoroalkylene group having 1-6 carbon atoms, or a divalent organic group having 2-6 carbon atoms in which alkylene unit(s) or fluoroalkylene unit(s) are bonded via one or more ether bonds.)