Non-Aqueous Electrolyte Additives for Metal Ion Elution Control

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Solution Overview

Problem

Lithium secondary batteries face degradation issues due to metal ion elution from the positive electrode, leading to deterioration of the negative electrode and reduced cycle characteristics, especially at high temperatures, causing swelling and instability.

Innovation Solution

A non-aqueous electrolyte is developed with a compound containing a propargyl group and an imidazole group as the first additive, and a polymer with specific repeating units as the second additive, which forms a stable and elastic solid electrolyte interface (SEI) film on the negative electrode, reducing side reactions and maintaining film integrity during charge and discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high-nickel positive electrode active material or high voltage is used to increase capacity, then energy density and output are improved, but metal ion elution from the positive electrode increases causing negative electrode deterioration

Engineering Contradiction:

Improveenergy density and outputVSAvoidnegative electrode stability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent introduces a compound containing both a propargyl group and an imidazole group as an intermediary substance in the non-aqueous electrolyte. This compound mediates between the positive and negative electrodes by suppressing metal ion elution from the positive electrode and promoting formation of a stable SEI film on the negative electrode, thereby preventing negative electrode deterioration while maintaining high capacity operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical composition parameters of the non-aqueous electrolyte by incorporating a specific compound with propargyl and imidazole functional groups. This parameter change alters the electrolyte's interaction characteristics with electrode surfaces, enabling suppression of side reactions and metal ion elution even under high-voltage and high-nickel conditions

Inventive Principle:

Principle #35Parameter changes

2Power

If the potential of the positive electrode is increased or the battery is exposed to high temperatures, then output and energy density are improved, but the cycle characteristics are degraded due to accelerated deterioration

Engineering Contradiction:

Improveoutput and energy densityVSAvoidcycle characteristics

Core Design Contradiction:

PowerVSDuration of action of stationary object

Solution Approach 1:

The patent applies preliminary anti-action by having the propargyl-imidazole compound proactively suppress deterioration mechanisms before they can significantly impact cycle life. The compound preemptively forms protective effects that counteract the accelerated degradation caused by high potential and high temperature exposure, thereby maintaining cycle characteristics despite aggressive operating conditions

Inventive Principle:

Principle #9Preliminary anti-action

3Quantity of substance

If the battery is continuously used for a long period or stored at high temperatures, then energy storage capacity is maintained, but gas generation causes swelling phenomenon

Engineering Contradiction:

Improveenergy storage capacityVSAvoidbattery thickness and swelling

Core Design Contradiction:

Quantity of substanceVSShape

Solution Approach 1:

The patent converts the potentially harmful side reactions that normally produce gas into beneficial effects. The propargyl-imidazole compound redirects reaction pathways to form stable SEI films instead of gaseous byproducts, thereby eliminating the swelling phenomenon while maintaining energy storage capacity during long-term use and high-temperature storage

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 solution significantly reduces metal ion elution, enhances the stability of the SEI film at high temperatures, improves cycle characteristics, and maintains the battery's performance and storage capacity over time.

Implementation Method 1

forming a stable SEI film on the negative electrode

Methodology Applied

Scientific EffectSolid electrolyte interphase (SEI) formation:

Implementation Method 2

capable of forming a stable ion conductive film on the surface of a negative electrode

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 3

a polymer including a repeating unit represented by Formula 2-1, Formula 2-2, and Formula 2-3 as a second additive

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11894520B2Non-aqueous electrolyte including additive for non-aqueous electrolyte, and lithium secondary battery including the non-aqueous electrolyte

Publication Date: 2024.02.06 LG ENERGY SOLUTION LTD

AI summary

The present disclosure provides a non-aqueous electrolyte including a lithium salt, an organic solvent, a compound represented by Formula 1 as a first additive, and a polymer including a repeating unit represented by Formula 2-1, Formula 2-2, and Formula 2-3 as a second additive:all the variables are described herein.