Lithium Secondary Battery Electrolyte for High-Voltage SEI Stabilization

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Solution Overview

Problem

Lithium secondary batteries using lithium manganese-rich positive electrode active materials face issues with gas generation and positive electrode deterioration during high-voltage activation, leading to rapid degradation of lifespan properties.

Innovation Solution

Incorporating a coumarin-based compound and a halogenated cyclic carbonate into the non-aqueous electrolyte to scavenge active oxygen generated during high-voltage activation, forming a stable solid electrolyte interface (SEI) film to reduce gas generation and electrode degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high-voltage activation (4.6 V or greater) is performed to activate lithium manganese-rich positive electrode active material, then battery energy density and voltage are improved, but active oxygen is generated causing electrolyte decomposition and positive electrode deterioration

Engineering Contradiction:

Improvebattery voltageVSAvoidpositive electrode stability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

A coumarin-based compound is introduced as an intermediary substance in the electrolyte that preferentially reacts with active oxygen generated during high-voltage activation. This mediator captures the harmful oxygen before it can attack the positive electrode structure, allowing high-voltage operation while protecting electrode integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The active oxygen generated during high-voltage activation, which is normally harmful to the electrode, is converted into a beneficial effect by having it react with the coumarin-based compound to form a protective film on the positive electrode surface. This film stabilizes the electrode structure while allowing the high-voltage activation process to proceed.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Power

If high-voltage activation is performed, then battery energy density is improved, but gas generation increases due to electrolyte decomposition

Engineering Contradiction:

Improvebattery voltageVSAvoidgas generation

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The coumarin-based compound acts as a mediator that intercepts active oxygen before it can decompose the electrolyte. By capturing oxygen in a controlled reaction, the compound prevents uncontrolled electrolyte decomposition that would otherwise generate harmful gases.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The coumarin-based compound is预先 introduced into the electrolyte to perform preliminary anti-action against active oxygen generation. During high-voltage activation, the compound is already present to immediately capture and neutralize oxygen as it is generated, preventing subsequent electrolyte decomposition and gas formation.

Inventive Principle:

Principle #9Preliminary anti-action

3Ease of manufacture

If hyper-lithium manganese-rich positive electrode active material is used to reduce manufacturing cost, then battery cost is reduced, but lifespan properties deteriorate due to positive electrode degradation

Engineering Contradiction:

Improvemanufacturing costVSAvoidbattery lifespan

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The coumarin-based compound serves as a protective intermediary that shields the cost-effective lithium manganese-rich positive electrode from degradation. By capturing active oxygen and forming a stabilizing film, the compound enables these cheaper materials to achieve acceptable lifespan properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The addition of the coumarin-based compound changes the chemical environment parameters at the positive electrode surface. It modifies the local chemistry by consuming active oxygen and forming stable reaction products, thereby changing the degradation kinetics and extending battery lifespan without altering the base electrode material composition.

Inventive Principle:

Principle #35Parameter changes

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 enhances the lifespan and swelling properties of lithium secondary batteries by suppressing gas generation and electrode deterioration, improving high-voltage performance and stability.

Implementation Method 1

a coumarin-based compound... and a halogen-substituted cyclic carbonate... to remove active oxygen generated during high-voltage activation

Methodology Applied

Scientific EffectOxygen scavenging: Absorption (physical)

Implementation Method 2

a coumarin-based compound... and a halogen-substituted cyclic carbonate... forms a stable solid electrolyte interphase (SEI) film

Methodology Applied

Scientific EffectSEI film formation: Deposition (physical)

Data Source

PatentUS12620626B2Lithium secondary battery

Publication Date: 2026.05.05 LG ENERGY SOLUTION LTD

AI summary

The present disclosure relates to a lithium secondary battery comprising a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, and a non-aqueous electrolyte. The non-aqueous electrolyte includes an organic solvent, a lithium salt, a coumarin-based compound represented by [Chemical Formula 1], and a halogen-substituted cyclic carbonate, and the positive electrode active material includes a lithium manganese-rich oxide represented by [Chemical Formula 2].