Sulfone Additive Prevents Gas Generation in Lithium Batteries
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Solution Overview
Problem
Lithium secondary batteries face issues with gas generation at high voltages, leading to degraded cycle properties and potential swelling, which compromises battery performance and safety.
Innovation Solution
A nonaqueous electrolytic solution containing a sulfone compound with a specific structure, such as bis(2-propynyl)sulfone or sulfone compounds represented by general formulas (I) and (II), is used, which prevents gas generation and enhances cycle properties by forming a dense surface film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the charge voltage is elevated to increase battery capacity, then the battery capacity is improved, but the electrolytic solution is more readily decomposed causing gas generation and worsening cycle property
Solution Approach 1:
The sulfone compound performs preliminary action by forming a protective surface film on the electrode before electrolyte decomposition can occur. This pre-formed film acts as a barrier that prevents subsequent decomposition reactions, allowing the battery to operate at high voltages without the electrolyte breaking down and generating gas during cycling.
Solution Approach 2:
The sulfone compound acts as an intermediary substance between the electrode and the electrolyte. It forms a surface film that mediates the interaction, preventing direct contact and harmful reactions between the electrolyte and electrode at high voltages, thus protecting the electrolyte from decomposition while maintaining battery capacity.
2Quantity of substance
If the density of the electrode is increased to increase battery capacity, then the battery capacity is improved, but the space volume for the nonaqueous electrolytic solution is decreased making the battery more susceptible to swelling from decomposition
Solution Approach 1:
The sulfone compound provides self-service by automatically forming a protective surface film on the electrode during initial cycles. This self-forming film continuously protects the electrode-electrolyte interface, preventing electrolyte decomposition and gas generation that would cause swelling, without requiring additional protective structures or components.
3Productivity
If the battery is used at high temperatures, then the battery performance is improved, but the solvent is reduced and decomposed on the negative electrode causing resistance increase and gas generation
Solution Approach 1:
The sulfone compound applies preliminary anti-action by forming a heat-resistant protective film on the electrode surface before thermal decomposition can occur. This pre-formed barrier resists the thermal stress and prevents the electrolyte from decomposing at high temperatures, thereby preventing gas generation while maintaining battery performance under thermal conditions.
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 effectively reduces gas generation and improves high-temperature cycle properties, maintaining battery performance and safety by preventing swelling and degradation.
Implementation Method 1
a nonaqueous electrolytic solution containing a sulfone compound with a specific structure, such as bis(2-propynyl)sulfone or sulfone compounds represented by general formulas (I) and (II), is used, which prevents gas generation and enhances cycle properties by forming a dense surface film
Data Source
AI summary
The present invention provides (1) a sulfone compounds having a propargyl group, (2) a nonaqueous electrolytic solution for lithium secondary batteries, which comprises an electrolyte salt dissolved in a nonaqueous solvent and contains a sulfone compound having a specific structure that has an SO2 group with a propargyl group or a vinyl group bonding thereto, in an amount of from 0.01 to 10% by weight of the nonaqueous electrolytic solution, and which can prevent gas generation and is excellent in battery characteristics such as cycle property and the like, and (3) a lithium secondary battery comprising a positive electrode, a negative electrode and a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, wherein the nonaqueous electrolytic solution contains a sulfone compound having a specific structure, in an amount of from 0.01 to 10% by weight of the nonaqueous electrolytic solution.