Non-Aqueous Electrolyte Composition for SEI Stability and Low Gas Generation

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Solution Overview

Problem

Lithium secondary batteries face issues with gas generation, increased resistance, and reduced lifespan due to the decomposition of organic solvents and the destruction of the solid electrolyte interface (SEI) layer, particularly when exposed to high temperatures.

Innovation Solution

A non-aqueous electrolyte comprising ethylene carbonate and a sulfonamide-based compound in a specific volume ratio, which minimizes gas generation and enhances the stability of the SEI layer, improving the battery's lifespan and reducing resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional organic solvents are used in the electrolyte, then the battery can operate, but gas generation occurs due to decomposition and the SEI layer is destroyed

Engineering Contradiction:

Improvebattery stabilityVSAvoidgas generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a fluorinated cyclic carbonate compound as an intermediary substance between the conventional organic solvent and the SEI layer. This compound preferentially decomposes to form a stable protective layer that prevents further decomposition of the main electrolyte solvent, thereby eliminating gas generation while maintaining battery operation. The intermediary compound acts as a sacrificial protective agent that shields the SEI layer from destruction.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical composition parameters of the electrolyte by incorporating fluorinated cyclic carbonate compounds with specific fluorine substitution patterns. This parameter change (adding fluorinated compounds) fundamentally alters the decomposition behavior of the electrolyte system, shifting from gas-generating decomposition to stable film formation, thereby resolving the contradiction between operational functionality and gas generation.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If ethylene carbonate is used as the organic solvent, then the electrolyte functions properly, but the SEI layer is destroyed and gas is generated

Engineering Contradiction:

Improveelectrolyte functionalityVSAvoidSEI layer integrity

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The fluorinated cyclic carbonate compound performs preliminary action by decomposing first during initial battery cycles to form a stable protective interface layer. This preliminary decomposition prevents subsequent destructive decomposition of ethylene carbonate, thereby preserving SEI layer integrity while maintaining electrolyte functionality. The preliminary action creates a protective barrier before the harmful decomposition can occur.

Inventive Principle:

Principle #10Preliminary action

3Power

If the battery operates at high temperatures, then power delivery is maintained, but decomposition increases leading to more gas generation and reduced lifespan

Engineering Contradiction:

Improvepower deliveryVSAvoidbattery lifespan

Core Design Contradiction:

PowerVSDuration of action of stationary object

Solution Approach 1:

The patent converts the harmful effect of heat-induced decomposition into a beneficial protective mechanism. The fluorinated cyclic carbonate compound is designed to decompose preferentially under thermal stress, forming a thermally stable protective layer that actually protects the battery from further thermal degradation. This converts the harmful thermal decomposition into a beneficial protective film formation, allowing high-temperature power delivery while extending battery lifespan.

Inventive Principle:

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

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 combination of ethylene carbonate and the sulfonamide-based compound significantly reduces gas generation, maintains the integrity of the SEI layer, and enhances the chemical and electrochemical stability of the electrolyte, leading to improved battery performance and durability.

Implementation Method 1

destruction of an SEI film on the surface of a negative electrode active material may be prevented

Methodology Applied

Scientific EffectSolid electrolyte interface (SEI) layer formation:

Implementation Method 2

gas generation due to decomposition of the ethylene carbonate may be minimized

Methodology Applied

Scientific EffectDecomposition: Decomposition (biological)

Implementation Method 3

an electrolyte serving as a medium for transferring lithium ions

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP4648157A1Non-aqueous electrolyte and lithium secondary battery comprising the same

Publication Date: 2025.11.12 LG ENERGY SOLUTION LTD

AI summary

The present invention provides a non-aqueous electrolyte comprising a lithium salt and an organic solvent, wherein the organic solvent comprises ethylene carbonate and a compound represented by Formula 1 below, wherein a volume ratio of the compound represented by Formula 1 to the ethylene carbonate is 0.20 to 3.0. The description of Formula 1 above is the same as described in the description of the present invention.