Lithium-Sulfur Battery Electrolyte Composition for Polysulfide Stability

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Solution Overview

Problem

The lifetime characteristics of lithium-sulfur secondary batteries are deteriorated due to the use of ether-based solvents, leading to issues such as lithium polysulfide leaching, dendrite growth, and electrolyte decomposition, which are exacerbated by high reactivity and increased viscosity during charging and discharging.

Innovation Solution

An electrolyte solution for lithium-sulfur secondary batteries comprising a non-aqueous solvent mixture of ether-based solvents and nonsolvents, specifically including linear and cyclic ethers, and a compound represented by Chemical Formula 1, with controlled volume ratios and additives to stabilize the electrolyte and improve lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ether-based solvents are used to improve sulfur reactivity, then lithium polysulfide dissolution and reactivity increase, but lifetime characteristics deteriorate due to leaching, dendrite growth, and electrolyte decomposition

Engineering Contradiction:

Improvesulfur reactivityVSAvoidbattery lifetime

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent introduces a novel compound (Formula 1) as an intermediary substance in the electrolyte that mediates between the ether-based solvent and lithium polysulfide. This intermediary prevents direct harmful interactions while maintaining beneficial dissolution, thereby extending battery lifetime without sacrificing sulfur reactivity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite electrolyte system combining ether-based solvent, lithium salt, and the novel Formula 1 compound. This composite formulation synergistically integrates the high reactivity benefit of ether solvents with the stability advantage of the Formula 1 additive, resolving the contradiction between reactivity and lifetime

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If electrolyte solution content is reduced to increase energy density, then energy density improves, but viscosity increases rapidly during charging and discharging

Engineering Contradiction:

Improveenergy densityVSAvoidviscosity

Core Design Contradiction:

Quantity of substanceVSForce

Solution Approach 1:

The patent modifies the chemical composition parameters of the electrolyte by introducing Formula 1 compound, which changes the physical properties of the electrolyte solution. This parameter change allows reduced electrolyte content while maintaining acceptable viscosity characteristics during battery operation

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If high sulfur loading is used to achieve high energy density, then energy density improves, but electrolyte decomposition and lifetime deterioration worsen

Engineering Contradiction:

Improveenergy densityVSAvoidelectrolyte stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The Formula 1 compound acts as a protective intermediary that stabilizes the interface between high sulfur loading and the electrolyte, preventing decomposition reactions while enabling high energy density operation

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 solution effectively prevents electrolyte decomposition and enhances the lifetime characteristics of lithium-sulfur secondary batteries by stabilizing the electrolyte and maintaining lithium ion mobility, even under high current densities.

Implementation Method 1

The lithium cation produced by the oxidation reaction of lithium is transferred to the positive electrode through the electrolyte

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

an ether-based solvent such as dioxolane and dimethoxy ethane, which are highly soluble for lithium polysulfide, is used as a solvent for the electrolyte solution

Methodology Applied

Scientific EffectSolvation: Solvation

Data Source

PatentUS12537227B2Liquid electrolyte for lithium-sulfur secondary battery and lithium-sulfur secondary battery comprising same

Publication Date: 2026.01.27 LG ENERGY SOLUTION LTD

AI summary

The present disclosure relates to an electrolyte solution for a lithium-sulfur secondary battery and a lithium-sulfur secondary battery comprising the same, more particularly to an electrolyte solution for a lithium-sulfur secondary battery containing a lithium salt and a non-aqueous solvent, wherein the non-aqueous solvent comprises an ether-based solvent and a nonsolvent, the ether-based solvent comprises a linear ether and a cyclic ether, and the nonsolvent comprises a compound having a specific structure.