Electrolyte Additives for Battery High Voltage Storage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithium-ion battery electrolytes, particularly those using lithium hexafluorophosphate and a mixture of cyclic and chain carbonate esters, exhibit poor high voltage and high temperature storage performance, necessitating the development of a more effective electrolyte composition to enhance energy density and charge-discharge capabilities.
Innovation Solution
Incorporating a sulfonic ester cyclic quaternary ammonium salt and a fluorocarbon surfactant into the electrolyte to form a dense, stable passive film on electrode surfaces, reducing impedance and improving infiltration, thereby enhancing rate capability, low temperature discharge performance, and high temperature storage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte composition (lithium hexafluorophosphate and carbonate ester mixture) is used, then basic battery function is maintained, but high voltage and high temperature storage performance deteriorates
Solution Approach 1:
The patent uses a composite electrolyte system combining lithium hexafluorophosphate salt with multiple additives (cyclic carboxylate, chain carbonate ester, and sulfone) in specific concentration ranges. This composite composition creates synergistic effects that improve high voltage and high temperature storage performance while maintaining basic battery function, directly resolving the technical contradiction between reliability and composition complexity.
2Reliability
If electrolyte additives are increased to improve performance, then storage performance improves, but internal impedance increases
Solution Approach 1:
The patent optimizes the concentration parameters of each electrolyte component, specifically setting cyclic carboxylate at 5-20%, chain carbonate ester at 70-85%, and sulfone at 5-20%. These precise parameter adjustments balance the formation of protective films (improving storage performance) while controlling internal impedance, resolving the contradiction between storage performance and harmful internal impedance.
3Quantity of substance
If voltage and press density of electrode active material are increased to improve energy density, then energy density improves, but charge-discharge rate capability deteriorates
Solution Approach 1:
The electrolyte additives act as intermediaries that facilitate efficient ion transport between high voltage and high density electrode materials. The cyclic carboxylate and sulfone components form conductive interfaces that mediate the charge-discharge process, enabling high energy density electrodes to maintain excellent rate capability by reducing interfacial resistance and improving electrolyte penetration.
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 combined effect of the sulfonic ester cyclic quaternary ammonium salt and fluorocarbon surfactant results in a lithium-ion battery with excellent rate capability, low temperature discharge performance, and high temperature storage performance by forming a dense solid electrolyte interface film and increasing electrolyte infiltration, thus preventing oxidation and reduction reactions and reducing internal impedance.
Implementation Method 1
a dense solid electrolyte interface film with low impedance can form on the surface of the negative electrode film
Implementation Method 2
infiltration capability of the electrolyte on the passive film of each of the positive electrode film and the negative electrode film can be increased
Data Source
AI summary
The present disclosure provides an electrolyte and an electrochemical energy storage device. The electrolyte comprises an electrolyte salt and an additive. The additive comprises a sulfonic ester cyclic quaternary ammonium salt and a fluorocarbon surfactant. Under the combined effect of the sulfonic ester cyclic quaternary ammonium salt and the fluorocarbon surfactant, a dense, uniform and stable passive film can form on a surface of each of a positive electrode film and a negative electrode film of the electrochemical energy storage device, and infiltration capability of the electrolyte on each of the passive film of the positive electrode film and the negative electrode film can be increased at the same time, so as to decrease electrode polarization inside the electrochemical energy storage device and make the electrochemical energy storage device have excellent rate capability, low temperature discharge performance and high temperature storage performance.