Lithium Battery Electrolyte Composition for SEI Protection at High Temperature

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Solution Overview

Problem

Lithium secondary batteries face issues with lifespan characteristics and high-temperature stability due to side reactions between the electrode and organic electrolytes, leading to deterioration and increased resistance.

Innovation Solution

An electrolyte composition for lithium secondary batteries comprising a lithium salt, a non-aqueous organic solvent, a first compound represented by Formula 1, and a second compound represented by Formula 2, which inhibits transition metal ion elution and forms a protective solid electrolyte interface (SEI) on the negative electrode, improving lifespan and high-temperature stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If an organic electrolyte including a lithium salt is used in lithium secondary batteries, then high energy density and fast charging speed are achieved, but lifespan characteristics and high-temperature stability deteriorate due to side reactions between electrodes and electrolyte

Engineering Contradiction:

Improveenergy densityVSAvoidlifespan characteristics

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces a protective film forming compound as an intermediary substance between the electrode and the organic electrolyte. This compound forms a stable protective film on the electrode surface, mediating the interaction between the electrode and electrolyte to prevent harmful side reactions while allowing lithium ion transport, thus resolving the contradiction between maintaining high energy density and improving lifespan characteristics

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical composition parameters of the electrolyte by adding specific protective film forming compounds with controlled concentrations. This parameter change transforms the electrolyte system from one that causes electrode degradation to one that forms protective interfaces, thereby improving reliability without sacrificing the energy density provided by the organic electrolyte system

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If an organic electrolyte including a lithium salt is used in lithium secondary batteries, then high energy density is achieved, but high-temperature stability deteriorates due to side reactions between electrodes and electrolyte

Engineering Contradiction:

Improveenergy densityVSAvoidhigh-temperature stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The protective film forming compound acts as a thermal stability mediator by forming a stable interface layer that prevents direct contact between the electrode and the thermally unstable organic electrolyte. This intermediary layer remains stable at high temperatures and prevents decomposition reactions, thereby improving high-temperature stability while preserving the high energy density characteristics of the organic electrolyte system

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite electrolyte system combining the original organic electrolyte with protective film forming compounds. This composite material approach integrates the high energy density benefits of organic electrolytes with the thermal stability provided by the protective film formers, achieving both high energy density and high-temperature stability simultaneously

Inventive Principle:

Principle #40Composite materials

3Ease of operation

If conventional electrolyte composition is used, then basic battery operation is maintained, but resistance increases and performance deteriorates due to electrode-electrolyte side reactions

Engineering Contradiction:

Improvebasic battery operationVSAvoidresistance stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The protective film forming compound serves as an intermediary that stabilizes the electrode-electrolyte interface. This film prevents direct harmful interactions while maintaining ionic conductivity, thereby preventing resistance increase and performance deterioration over time, while preserving basic battery operation characteristics

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enhances room-temperature lifespan and high-temperature storage properties by suppressing metal ion elution and forming a stable SEI, reducing resistance and maintaining battery performance.

Implementation Method 1

not only elution of transition metal ions by an electrolytic solution may be inhibited at room temperature and a high temperature (60° C.)

Methodology Applied

Scientific EffectIon elution inhibition:

Implementation Method 2

a solid electrolyte interface (SEI) on the surface of a negative electrode may be protected

Methodology Applied

Scientific EffectSolid electrolyte interface formation:

Data Source

PatentUS20250210712A1Electrolyte for lithium secondary battery and lithium secondary battery comprising same

Publication Date: 2025.06.26 SAMSUNG SDI CO LTD

AI summary

Disclosed are an electrolyte for lithium secondary batteries and a lithium secondary battery including the same. The electrolyte for lithium secondary batteries includes: a lithium salt; a non-aqueous organic solvent; a compound represented by Formula 1 disclosed in the specification; and a compound represented by Formula 2 disclosed in the specification.