Battery Electrolyte Composition for Stable Electrode Interface Films
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Solution Overview
Problem
Lithium-ion batteries experience poor power performance, cycling performance, and high-temperature storage performance due to side reactions at the electrode interfaces, leading to instability and consumption of active lithium during the formation of the SEI film.
Innovation Solution
An electrolyte solution comprising a first additive with a sulfate ester group, a second additive that decomposes to form a CEI film, and a third additive that enhances the positive electrode interface, with specific content ratios to stabilize the SEI and CEI films, reducing impedance and preventing lithium consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte solution is used, then battery can operate, but side reactions occur at electrode interfaces resulting in poor power performance, cycling performance, and high-temperature storage performance
Solution Approach 1:
The patent introduces a multi-component additive system (first additive with sulfate ester group, second additive, and third additive) that acts as intermediaries between the electrolyte and electrode interfaces. These additives preferentially react to form stable protective films (SEI at negative electrode, CEI at positive electrode) that prevent harmful side reactions between the electrolyte and electrodes, thereby improving cycling performance and reliability
Solution Approach 2:
The patent employs a composite additive system combining three different types of additives with specific functional properties. The first additive (sulfate ester compound) forms the primary SEI film, the second additive enhances film stability, and the third additive进一步优化 the interface properties. This composite approach creates synergistic effects that collectively suppress side reactions and improve battery performance
2Reliability
If SEI film forms at negative electrode, then electrolyte is consumed, but this results in poor power performance and cycling performance
Solution Approach 1:
The additives in the electrolyte perform preliminary action by preferentially reacting with the electrode surfaces during initial cycles to form stable, low-resistance SEI and CEI films. This preliminary film formation prevents subsequent electrolyte decomposition and consumption, maintaining electrolyte availability and improving power performance while reducing harmful substance loss
3Reliability
If conventional additives are used, then some protection is provided, but high-temperature storage performance remains poor due to ongoing side reactions
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by introducing specific additives with defined molecular structures and properties. The first additive (sulfate ester compound), second additive, and third additive have specific functional groups that change the interfacial chemistry parameters, creating more stable films that resist thermal degradation and oxidation, thereby improving high-temperature storage performance and electrolyte stability
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 stabilized films improve power performance, cycling performance, and high-temperature storage performance by inhibiting electrolyte decomposition and oxidation, maintaining lithium availability and enhancing ionic conductivity.
Implementation Method 1
the first additive includes a sulfate ester compound... can participate in film formation at the negative electrode interface, effectively inhibit the reduction and decomposition of the electrolyte solution
Implementation Method 2
the second additive... can participate in film formation at the positive electrode interface, effectively inhibit the oxidation of the electrolyte solution
Implementation Method 3
Lithium-ion batteries are widely used... due to their outstanding characteristics
Data Source
Figure 1~3
Figure 4~5
AI summary
The present application discloses an electrolyte solution, a battery and an electrical device. The electrolyte solution includes a first additive, a second additive and a third additive. The first additive includes a sulfate ester compound. The second additive includes: , where Z1-Z4 each independently include an oxygen atom or a sulfur atom. The third additive includes at least one of fluorosulfonate, tetrafluoroborate, difluorophosphate, difluoro(oxalato)borate, bis(oxalato)borate and difluorobis(oxalato)phosphate. Based on the total mass of the electrolyte solution, content W1 of the first additive, content W2 of the second additive and content W3 of the third additive satisfy W1:W2:W3=1:(0.1-1.5):(0.02-2.5).