Battery Electrolyte Additive for Tougher SEI and Longer Cycle Life
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Solution Overview
Problem
Conventional electrolytic solutions for lithium metal batteries release active oxygen during charging and discharging, leading to oxidation reactions that negatively affect battery cycle performance and safety.
Innovation Solution
An electrolytic solution containing a functional compound with specific structures, including a phosphite ester group and silicon-containing groups, captures fluorine-containing byproducts and acidic substances, promoting the formation of robust SEI films to enhance cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional electrolytic solutions are used in lithium metal batteries, then the battery can operate with high theoretical energy density, but the electrolytic solution undergoes oxidation reactions releasing active oxygen during charging and discharging, which negatively affects cycle performance and safety
Solution Approach 1:
The patent converts the harmful oxidation products (active oxygen and acidic substances) into beneficial effects by introducing functional compounds that capture these byproducts. The phosphite ester group captures fluorine-containing oxidation products, while the silicon-containing group captures acidic substances, transforming the harmful oxidation reactions into a controlled process that forms protective SEI films and improves battery cycle performance
Solution Approach 2:
The functional compound acts as an intermediary between the electrolytic solution and the electrode. It mediates the oxidation reactions by capturing harmful byproducts and promoting the formation of stable SEI films, thereby protecting the electrode from direct damage while maintaining the high energy density benefits of lithium metal batteries
2Device complexity
If conventional electrolytic solutions are used, then the battery structure can be kept simple, but oxidation reactions occur during charging and discharging causing safety accidents
Solution Approach 1:
The patent transforms the safety hazard of oxidation reactions by introducing functional compounds with specific groups that capture harmful byproducts. The phosphite ester group captures fluorine-containing substances, and the silicon-containing group captures acidic substances, converting potentially dangerous oxidation reactions into a controlled process that enhances safety
Solution Approach 2:
The patent changes the chemical parameters of the electrolytic solution by introducing functional compounds with specific structural groups. This modification alters the reaction pathways of oxidation, directing them toward beneficial SEI film formation rather than harmful active oxygen release, thereby improving safety without significantly increasing complexity
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 improves the toughness of SEI films, capturing oxidation products and enhancing the cycle performance of secondary batteries.
Implementation Method 1
the phosphite ester structural group exhibits nucleophilicity, can capture fluorine-containing byproducts formed by oxidation of the electrolytic solution
Implementation Method 2
the silicon-containing group captures acidic substances formed by oxidative decomposition of the electrolytic solution
Implementation Method 3
the silicon-containing group captures acidic substances formed by oxidative decomposition of the electrolytic solution and can participate in the formation of SEI films
Data Source
Figure 1~2
Figure 3~5
AI summary
An electrolyte, a secondary battery and an electrical apparatus. The components of the electrolyte comprise a functional compound represented by formula (1). In formula (1), T1-T3 are each independently selected from any one of an alkyl group having 1-10 carbon atoms, an alkenyl group having 2-10 carbon atoms, an alkynyl group having 2-10 carbon atoms, and groups represented by following formulae (a)-(f). Among T1-T3, at least one is selected from the group represented by formula (a), and at least one is selected from the group represented by formula (b), (c), (d) or (e). In a charging/discharging process of the electrolyte, the functional compound represented by formula (1) can capture an oxidation product and improve the toughness of a formed SEI film, thereby improving the cycle performance of a secondary battery.