Non-Aqueous Electrolyte Composition for High-Voltage Lithium Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electrolytes for lithium secondary batteries do not effectively inhibit side reactions at both the positive and negative electrodes, especially under high voltage conditions, leading to reduced battery performance and safety risks.
Innovation Solution
A non-aqueous electrolyte composition comprising a specific electrolyte additive represented by Chemical Formula 1, which forms a protective film on both positive and negative electrodes, expanding the oxidation potential window to 4.5V or more, and includes a non-aqueous organic solvent with ester-based solvents and co-solvents to enhance stability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte additives (succinonitrile, adiponitrile, glutaronitrile) are used to protect the positive electrode, then thermal properties and high temperature performance are improved, but side reactions at the negative electrode are not inhibited
Solution Approach 1:
The patent divides the electrolyte protection function into two separate additive components: a nitrile-based additive (succinonitrile, adiponitrile, or glutaronitrile) for positive electrode protection, and a vinylene carbonate additive for negative electrode protection. This segmentation allows each additive to specialize in protecting one electrode without interfering with the other, resolving the contradiction between positive electrode protection and negative electrode side reactions.
Solution Approach 2:
The patent introduces vinylene carbonate as an intermediary substance that mediates the interaction between the electrolyte and the negative electrode. This intermediary forms a protective film on the negative electrode surface, preventing direct contact and side reactions between the electrolyte and negative electrode active material, while allowing the nitrile-based additive to independently protect the positive electrode.
2Quantity of substance
If high voltage positive electrode active materials are used to increase energy density, then the oxidation potential window of the electrolyte becomes narrower than the potential window of the electrode active material, but side reactions increase
Solution Approach 1:
The patent applies preliminary action by having the nitrile-based electrolyte additives react first with the high voltage positive electrode active material surface to form a stable protective film before the electrolyte can undergo decomposition. This pre-formed protective layer prevents subsequent side reactions and electrolyte decomposition, allowing the use of high voltage materials for increased energy density without compromising electrolyte stability.
Solution Approach 2:
The patent uses small amounts of sacrificial electrolyte additives (succinonitrile, adiponitrile, or glutaronitrile) that are consumed to form protective films on the positive electrode surface. These additives act as disposable protective agents that sacrifice themselves to create a stable interface, enabling the electrolyte to maintain stability against high voltage positive electrode materials throughout the battery's operational life.
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 electrolyte composition improves oxidation stability, inhibits decomposition at high voltages, enhances battery life, and reduces the risk of explosion by maintaining a wide oxidation potential window, thereby supporting high-energy density applications.
Implementation Method 1
the nitrile groups are strongly bonded to transition metals such as cobalt on the positive electrode surface, and the metal-ligand bonds inhibit various interfacial side reactions
Data Source
AI summary
Disclosed herein relates to an electrolyte composition for a lithium secondary battery, wherein the electrolyte composition comprises an electrolyte additive represented by Chemical Formula 1 and has an oxidation potential window at 4.5 V or more, has and thus provides the advantage of removing oxidative degradation of the electrolyte composition during charging and discharging of the battery under high voltage conditions,wherein all the variables are described herein.