Sulfonic Ester Electrolyte for Battery Temperature Stability
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Solution Overview
Problem
Lithium secondary batteries face deterioration in electrochemical characteristics across a broad temperature range due to decomposition of nonaqueous electrolytic solutions, affecting lithium ion migration and battery performance.
Innovation Solution
A nonaqueous electrolytic solution is developed by adding specific sulfonic ester compounds, such as those with methine protons or cycloalkyl groups, to improve electrochemical characteristics by forming a protective coating film on electrodes, reducing decomposition and enhancing low-temperature properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional nonaqueous electrolytic solutions are used, then battery capacity is maintained, but decomposition occurs at high temperatures causing deterioration of electrochemical characteristics in broad temperature range
Solution Approach 1:
The patent applies preliminary action by having the sulfonic ester compound react in advance during initial charging cycles to form a stable protective coating film on the negative electrode surface. This pre-formed coating prevents subsequent decomposition of the electrolytic solution at high temperatures and maintains electrochemical characteristics across broad temperature ranges. The compound is specifically designed to react preferentially with the electrode surface before the main electrolyte components can decompose.
Solution Approach 2:
The sulfonic ester compound acts as an intermediary substance that mediates between the negative electrode and the nonaqueous electrolytic solution. It forms an intermediate protective coating layer that prevents direct contact and harmful reactions between the electrode and electrolyte, particularly preventing decomposition at high temperatures while still allowing lithium ion transport. This intermediary layer resolves the contradiction by providing thermal stability without sacrificing electrochemical performance.
2Stability of the object's composition
If protective coating is formed on negative electrode, then decomposition is reduced, but lithium ion migration may be hindered
Solution Approach 1:
The patent applies local quality by creating a protective coating with spatially varying properties - the coating is formed locally on the negative electrode surface where decomposition occurs, but its composition and structure are optimized to maintain local lithium ion conductivity. The sulfonic ester compound forms a coating that is protective against decomposition while containing channels or regions that facilitate lithium ion transport, thus resolving the contradiction between protection and ion migration.
Solution Approach 2:
The patent utilizes parameter changes by controlling the composition, thickness, and structure of the protective coating through selection of specific sulfonic ester compounds and charging conditions. The coating parameters are optimized to achieve the right balance - thick enough to prevent decomposition but thin and conductive enough to allow lithium ion migration. The compound structure parameters (R groups, molecular weight) are adjusted to achieve desired coating 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 significantly improves electrochemical characteristics across a broad temperature range, particularly at low temperatures after high-temperature storage, by minimizing decomposition and maintaining battery performance.
Implementation Method 1
decomposed products and gases generated from a solvent in a nonaqueous electrolytic solution which is reduced and decomposed on a surface of a negative electrode
Implementation Method 2
a negative electrode containing a material which can absorb and release lithium
Implementation Method 3
a nonaqueous electrolytic solution containing a lithium salt and a nonaqueous solvent
Data Source
AI summary
The present invention provides a nonaqueous electrolytic solution which can improve the electrochemical characteristics in a broad temperature range, an electrochemical element produced by using the same and a sulfonic ester compound having a branched structure which is used for the same.The present invention relates to a nonaqueous electrolytic solution prepared by dissolving an electrolyte salt in a nonaqueous solvent, which comprises a sulfonic ester compound represented by the following Formula (I) in an amount of 0.001 to 5% by mass of the nonaqueous electrolytic solution:(wherein R represents an alkyl group or an aryl group; A represents a >CH group or a >SiZ group (Z represents an alkyl group or an aryl group); X represents an alkyl group, a cycloalkyl group or an aryl group; Y represents a cycloalkyl group, a -L1CHRaOSO2Rb group or a —Si(Rc)(Rd)OSO2Rb group; W represents 1 or 2; Ra represents an alkyl group; Rb, Rc and Rd represent an alkyl group or an aryl group; L1 represents an alkylene group in which at least one hydrogen atom may be substituted with —OSO2Re (Re has the same meaning as that of R), a divalent linkage group containing at least one ether bond or a single bond).