Non-Aqueous Electrolyte Additive for High-Voltage Lithium Batteries

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Solution Overview

Problem

Lithium secondary batteries face degradation under high voltage and high temperature conditions due to electrolyte decomposition, leading to film destruction and transition metal ion elution, which deteriorates performance and generates gas.

Innovation Solution

Incorporation of a compound with a propargyl group bonded to coumarin in the non-aqueous electrolyte to suppress electrolyte decomposition and form a stable film on the electrodes, along with optional additives to enhance stability and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If lithium secondary batteries are driven under high voltage and high temperature conditions, then power and energy density are improved, but electrolyte decomposition occurs leading to film destruction and performance deterioration

Engineering Contradiction:

ImprovepowerVSAvoidelectrolyte stability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent introduces a coumarin derivative compound as an intermediary substance in the electrolyte that mediates between the high voltage/temperature conditions and the electrode film. This compound preferentially reacts with decomposition products (PF5, HF) to form a protective film, preventing direct damage to the electrode surface film and maintaining electrolyte stability under harsh operating conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical composition parameters of the electrolyte by incorporating specific coumarin derivatives with particular molecular structures (Formula 1). This parameter change in electrolyte composition enables the system to maintain stability at high voltage and temperature by altering the chemical reactivity and film-forming characteristics of the electrolyte system.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If lithium secondary batteries are driven under high voltage and high temperature conditions, then energy density is improved, but decomposition reactions increase causing performance deterioration

Engineering Contradiction:

Improveenergy densityVSAvoiddecomposition reaction

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful decomposition reactions into a beneficial protective mechanism. The coumarin derivative compound intentionally undergoes controlled decomposition to form a stable protective film on the electrode surface. This film then prevents further harmful decomposition reactions, effectively converting the initial decomposition harm into a long-term protective benefit that maintains energy density.

Inventive Principle:

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

3Power

If conventional electrolytes are used to achieve high power, then initial capacity is improved, but high-temperature durability deteriorates due to film destruction

Engineering Contradiction:

Improveinitial capacityVSAvoidhigh-temperature durability

Core Design Contradiction:

PowerVSDuration of action of stationary object

Solution Approach 1:

The coumarin derivative compound performs preliminary protective action by forming a stable film on the electrode surface before significant degradation occurs. This preliminary film formation prevents subsequent film destruction that would otherwise happen under high-temperature operation, thereby extending the duration of battery performance and improving high-temperature durability.

Inventive Principle:

Principle #10Preliminary action

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 reduces electrolyte decomposition, suppresses transition metal elution, and improves the battery's initial capacity, high-temperature durability, and cycle life, especially with high-Ni positive electrode active materials.

Implementation Method 1

when a lithium secondary battery is driven under high voltage and/or high temperature conditions, PF6− anions may be thermally decomposed from lithium salts such as LiPF6 contained in an electrolyte

Methodology Applied

Scientific EffectThermal decomposition: Decomposition (biological)

Implementation Method 2

a compound having a structure in which a propargyl group is bonded to coumarin

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

forming a reinforced film on the electrode

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Data Source

PatentUS12620621B2Non-aqueous electrolyte for lithium secondary battery and lithium secondary battery comprising same

Publication Date: 2026.05.05 LG ENERGY SOLUTION LTD

AI summary

The present disclosure relates to a non-aqueous electrolyte for a lithium secondary battery, including a lithium salt, an organic solvent and a compound represented by Chemical Formula 1; and a lithium secondary battery including the same,wherein R1, R2, L and m are described herein.