Lithium-Sulfur Battery Electrolyte for Polysulfide Shuttle Suppression

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Solution Overview

Problem

The commercialization of lithium-sulfur batteries is hindered by the reduction in charging/discharging efficiency and lifetime due to side reactions, lithium polysulfide leaching, and dendrite formation, which are not effectively addressed by existing electrolyte solutions.

Innovation Solution

An electrolyte solution for lithium secondary batteries comprising a heterocyclic compound with double bonds and oxygen or sulfur atoms, an ether-based solvent, lithium salt, zirconium oxynitrate, and lithium nitrate, optimized in specific ratios to form a protective film and suppress polysulfide shuttling, enhancing coulombic efficiency and lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolyte solutions are used in lithium-sulfur batteries, then the battery can operate, but the lifetime is reduced due to polysulfide shuttling and side reactions

Engineering Contradiction:

Improvebattery lifetimeVSAvoidpolysulfide shuttling and side reactions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces lithium nitrate and zirconium oxynitrate as intermediary substances that mediate between the polysulfide and lithium metal. These additives form protective films and complexes that prevent direct harmful interactions, reducing polysulfide shuttling and side reactions while maintaining battery operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrolyte uses a composite formulation combining multiple components: cyclic carbonate, chain carbonate, lithium salt, lithium nitrate, and zirconium oxynitrate. This composite electrolyte system works synergistically to suppress polysulfide shuttling, form protective films, and improve battery lifetime through multiple mechanisms

Inventive Principle:

Principle #40Composite materials

2Reliability

If lithium polysulfide is highly soluble in the electrolyte solution, then ion conductivity is improved, but the shuttle phenomenon increases and capacity decreases

Engineering Contradiction:

Improveion conductivityVSAvoidpolysulfide loss due to shuttling

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the chemical parameters of the electrolyte by adding lithium nitrate and zirconium oxynitrate, which alter the solvation environment. These parameter changes reduce polysulfide solubility and promote protective film formation, thereby reducing shuttling while maintaining sufficient ion conductivity for battery operation

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If lithium metal is used as the negative electrode, then high capacity is achieved, but dendrite formation occurs causing short circuits

Engineering Contradiction:

Improvebattery capacityVSAvoiddendrite formation

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The lithium nitrate and zirconium oxynitrate in the electrolyte perform preliminary action by forming protective films on the lithium metal surface before dendrites can form. This pre-protection mechanism prevents subsequent harmful dendrite growth while allowing lithium ions to pass for high capacity operation

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 improves the capacity and lifetime of lithium secondary batteries by forming a protective film on the lithium metal surface, reducing side reactions, and enhancing ion conductivity, thereby improving cycle lifetime and coulombic efficiency.

Implementation Method 1

combining a solvent, a lithium salt, and an additive contained in the electrolyte solution of the lithium secondary battery in an optimal ratio... forming a protective film on the lithium metal surface

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Implementation Method 2

since polysulfide leached from the positive electrode has high solubility in the organic electrolyte solution, it can undesirably move toward the negative electrode (PS shuttling) through the electrolyte solution

Methodology Applied

Scientific EffectSolvation: Solvation

Implementation Method 3

The electrolyte solution when sulfur in the positive electrode is leached into the electrolyte solution in the form of lithium polysulfide (LiPS) is called Catholyte

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP4117072B1Electrolyte for lithium secondary battery, and lithium secondary battery comprising the same

Publication Date: 2025.11.26 LG ENERGY SOLUTION LTD

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AI summary

Disclosed is an electrolyte solution for a lithium secondary battery, which is capable of improving the capacity and lifetime of the lithium secondary battery by combining a solvent, a lithium salt, and an additive contained in the electrolyte solution of the lithium secondary battery in an optimal ratio, and a lithium secondary battery comprising the same. The electrolyte solution for the lithium secondary battery comprises a first solvent comprising a heterocyclic compound containing one or more double bonds and at the same time containing any one of an oxygen atom and a sulfur atom; a second solvent comprising at least one of an ether-based compound, an ester-based compound, an amide-based compound, and a carbonate-based compound; lithium salt; zirconium oxynitrate; and lithium nitrate.