Battery Electrolyte Additive Ratios 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.
Innovation Solution
An electrolyte solution comprising a first additive with a sulfate ester compound, a second additive with specific decomposition products, and a third additive that enhances film formation at both positive and negative electrodes, forming stable solid electrolyte interfaces (SEI and CEI films) to inhibit decomposition and oxidation reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte solution is used, then the 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 film-forming additives (first additive with sulfate ester compound, second additive with specific decomposition products, and third additive) as intermediary substances that mediate between the electrolyte solution and electrode interfaces. These additives preferentially react to form stable protective films (SEI and CEI films) that prevent direct contact between the electrolyte and electrodes, thereby eliminating harmful side reactions while maintaining battery operation
Solution Approach 2:
The additives perform preliminary protective action by forming stable solid electrolyte interface (SEI) and cathode electrolyte interface (CEI) films before the electrolyte can undergo harmful side reactions with the electrodes. This preliminary film formation prevents subsequent decomposition and oxidation reactions, addressing the technical contradiction by preemptively blocking harmful pathways
2Productivity
If electrolyte solution reacts with electrodes, then ion transport occurs, but continuous consumption of active lithium reduces cycling performance and storage stability
Solution Approach 1:
The protective films formed by the additives act as intermediary layers that enable ion transport while preventing direct reaction between the electrolyte and electrodes. These films serve as selective barriers that allow lithium ions to pass through while blocking further consumption of active lithium, thus resolving the contradiction between maintaining productivity and preventing substance loss
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte interface by introducing specific additives in controlled amounts (W1:W2:W3=1:(0.1-1.5):(0.02-2.5)). These parameter changes transform the interface properties to achieve both efficient ion transport and prevention of active lithium consumption
3Stability of the object's composition
If film-forming additives are added to electrolyte, then electrode interface stability improves, but electrolyte composition complexity increases
Solution Approach 1:
The patent optimizes the composition parameters by specifying precise weight ratio ranges (W1:W2:W3=1:(0.1-1.5):(0.02-2.5)) and individual content ranges for each additive. This parameter optimization achieves effective interface stability while controlling composition complexity through defined concentration boundaries
Solution Approach 2:
The additives are concentrated at the electrode interfaces where they are most needed, creating local quality enhancement at the critical interface regions. The bulk electrolyte composition remains relatively simple while the interface regions gain enhanced stability properties through the localized presence of film-forming additives
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 power performance, cycling performance, and high-temperature storage performance by stabilizing the SEI and CEI films, reducing impedance, and preventing continuous consumption of active lithium.
Implementation Method 1
participate in film formation at the negative electrode interface
Implementation Method 2
inhibit the reduction and decomposition of the electrolyte solution at the negative electrode
Implementation Method 3
participate in film formation at the positive electrode interface
Implementation Method 4
inhibit the oxidation of the electrolyte solution at the positive electrode
Implementation Method 5
assist the second additive in film formation
Data Source
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).