Lithium-Sulfur Battery Electrolyte Additives for Dendrite Suppression

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Solution Overview

Problem

The formation of lithium dendrites in lithium-sulfur batteries leads to degradation of the negative electrode, reducing the battery's lifetime and coulombic efficiency due to reactions with the positive electrode active material or electrolyte solution, which can cause internal short circuits and stability issues.

Innovation Solution

Incorporating dioxolane-based derivatives as additives in the electrolyte solution to form a protective film on the negative electrode surface through ring opening polymerization, thereby suppressing dendrite formation and improving deposition and peeling processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium metal is used as the negative electrode to achieve high specific capacity, then energy density is improved, but dendrite formation occurs leading to reduced reliability

Engineering Contradiction:
Improvespecific capacityVSAvoiddendrite formation
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

A protective film is introduced as an intermediary layer between the lithium metal negative electrode and the electrolyte solution. This film acts as a mediator that prevents direct harmful interactions while allowing beneficial lithium ion transport, thereby suppressing dendrite formation without compromising the high specific capacity of lithium metal

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The chemical composition and physical properties of the electrolyte solution are modified by adding specific additives that change the parameters of the interface between the electrolyte and lithium metal. These parameter changes lead to the formation of a stable protective film that suppresses dendrite growth while maintaining high lithium ion conductivity

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional electrolyte composition is used, then manufacturing simplicity is maintained, but protective film formation is insufficient leading to reduced battery lifetime

Engineering Contradiction:
Improveelectrolyte preparationVSAvoidbattery lifetime
Core Design Contradiction:
Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The electrolyte solution is formulated as a composite system combining conventional electrolyte components with specific additive substances. This composite approach maintains the ease of manufacture associated with conventional electrolytes while introducing new functional properties that enable protective film formation and extend battery lifetime

Inventive Principle:
Principle #40Composite materials

3Device complexity

If lithium deposition and peeling processes are not optimized, then manufacturing complexity is reduced, but dendrite formation increases causing internal short circuits

Engineering Contradiction:
Improveprocess controlVSAvoidinternal short circuit prevention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The electrolyte solution with added additives enables the lithium metal surface to self-form a protective film during initial cycles. This self-service mechanism automatically optimizes the deposition and peeling processes without requiring external control systems or complex manufacturing procedures, thereby preventing dendrite formation and internal short circuits

Inventive Principle:
Principle #25Self-service

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 addition of dioxolane-based additives reduces dendrite formation, enhancing the battery's lifetime and coulombic efficiency by forming a protective film on the lithium-based metal surface.

Implementation Method 1

form a protective film on the negative electrode surface through ring opening polymerization

Methodology Applied
Scientific EffectRing opening polymerization: Photopolymerisation

Data Source

PatentEP4199169B1Electrolyte for lithium-sulfur battery and lithium-sulfur battery comprising same
Publication Date: 2025.07.30 LG ENERGY SOLUTION LTD

AI summary

The present invention relates to an electrolyte solution for a lithium-sulfur battery comprising a lithium salt, an organic solvent and an additive, wherein the additive comprises a compound represented by Formula 1, and therein R1 to R6 are the same as or different from each other, and are each independently selected from the group consisting of hydrogen; deuterium; a substituted or unsubstituted C1 to C60 alkyl group; a substituted or unsubstituted C6 to C60 aryl group; a substituted or unsubstituted C1 to C60 alkoxy group; and a substituted or unsubstituted C6 to C60 aryloxy group, and at least one of R1 to R6 is not H, and a lithium-sulfur battery containing the same.