Electrolyte Additive for High-Voltage Lithium-Ion Battery Stability
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Solution Overview
Problem
Lithium-ion batteries face performance degradation and decomposition at high voltages due to electrolyte degradation, leading to reduced cycling performance, as existing additives fail to provide sufficient protection and trigger side reactions.
Innovation Solution
An electrolyte composition including a compound represented by formula (I) with specific functional groups, along with additives like fluoroethylene carbonate and nitrile compounds, is used to form a protective film that inhibits contact between the positive active material and the electrolyte, improving high-temperature cycling performance and reducing resistance growth rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the voltage upper limit of lithium-ion batteries is increased to achieve high energy density, then the energy density is improved, but the electrolyte experiences performance degradation and decomposition due to structural damage of electrodes
Solution Approach 1:
The patent introduces a protective film as an intermediary layer between the positive electrode and the electrolyte. This film, formed by the compound of formula (I), acts as a mediator that prevents direct contact and harmful interactions between the electrolyte and electrode at high voltages, thereby resolving the contradiction between achieving high energy density through increased voltage and maintaining electrolyte stability
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by introducing a compound of formula (I) with specific functional groups (nitrile, isocyanate, or thiocyanate groups). This parameter change enables the formation of a stable protective film on the electrode surface, allowing the battery to operate at higher voltages without electrolyte decomposition, thus resolving the contradiction between high voltage operation and electrolyte stability
2Reliability
If existing electrolyte additives are used to protect electrodes at high voltages, then some protection is provided, but side reactions are triggered which further deteriorate battery performance
Solution Approach 1:
The patent changes the chemical structure parameters of the protective additive by using a compound of formula (I) containing specific functional groups (nitrile, isocyanate, or thiocyanate). This structural modification allows the additive to form a stable protective film without triggering harmful side reactions, thus resolving the contradiction between providing electrode protection and avoiding side reactions that deteriorate battery performance
Solution Approach 2:
The patent creates a composite protective layer on the electrode surface through the compound of formula (I), which combines multiple functional groups (nitrile, isocyanate, or thiocyanate) in a single molecular structure. This composite functional approach enables effective electrode protection at high voltages without inducing side reactions, resolving the contradiction between protection effectiveness and chemical 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 proposed electrolyte composition significantly enhances the high-temperature cycling performance and reduces the cycling resistance growth rate of lithium-ion batteries under high voltage conditions by forming a protective film and stabilizing the electrode structures.
Implementation Method 1
form a protective film that inhibits contact between the positive active material and the electrolyte
Implementation Method 2
lithium-ion batteries
Data Source
AI summary
An electrolyte, including a carbonyl triazole compound or a thiocarbonyl triazole compound. Also, an electrochemical apparatus including a positive electrode, a negative electrode, and the electrolyte, and an electronic apparatus including the electrochemical apparatus. The electrolyte can improve high-temperature cycling performance of electrochemical apparatuses under high voltage conditions and reduce cycling resistance growth rate of the electrochemical apparatuses.