Non-Aqueous Electrolyte Additive for Low-Resistance High-Temperature SEI

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Solution Overview

Problem

Lithium ion batteries experience performance degradation due to the dissolution of transition metal ions from the positive electrode, leading to increased resistance and reduced lifespan, especially at high temperatures, necessitating a stable and low-resistance film formation on the electrode surface.

Innovation Solution

Incorporating a compound represented by Formula 1, which includes a fluorine-substituted alkyl group and a propargyl group, as an additive in the non-aqueous electrolyte to form a robust, low-resistance film on the electrode surface, enhancing high-temperature durability and cycle characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the potential of the positive electrode is increased to achieve higher energy density, then the energy density is improved, but the dissolution of transition metal ions is accelerated and the structural collapse occurs more rapidly

Engineering Contradiction:

Improveenergy densityVSAvoidelectrode stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces a fluorinated cyclic carbonate compound as an intermediary substance that mediates between the high-potential positive electrode and the electrolyte. This compound forms a protective interface layer that prevents direct harmful interactions, allowing the system to operate at higher potentials without suffering from accelerated ion dissolution and structural collapse.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If the battery is exposed to high temperature to improve reaction kinetics, then the charge-discharge rate is improved, but the performance degradation is accelerated

Engineering Contradiction:

Improvecharge-discharge rateVSAvoidbattery lifetime

Core Design Contradiction:

SpeedVSDuration of action of stationary object

Solution Approach 1:

The patent applies beforehand cushioning by pre-forming a protective film on the electrode surface using the fluorinated cyclic carbonate compound before the battery undergoes high-temperature operation. This pre-formed protective layer acts as a cushion that prevents thermal degradation and slows down performance deterioration during high-temperature charge-discharge cycles.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If conventional electrolyte compositions are used to maintain simplicity, then the device complexity is reduced, but the SEI film stability at high temperature deteriorates

Engineering Contradiction:

Improveelectrolyte composition complexityVSAvoidSEI film stability

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition parameters of the electrolyte - specifically incorporating a fluorinated cyclic carbonate compound with distinct molecular characteristics. This parameter change transforms the SEI film formation behavior, resulting in films with enhanced thermal stability and oxidation resistance while maintaining reasonable electrolyte system complexity.

Inventive Principle:

Principle #35Parameter changes

4Quantity of substance

If the positive electrode potential is increased to utilize high-capacity materials, then the capacity is improved, but the transition metal ion dissolution increases

Engineering Contradiction:

Improvebattery capacityVSAvoidion dissolution

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potentially harmful high-potential environment into a beneficial condition by using the fluorinated cyclic carbonate compound to form a protective interface. This interface layer transforms the harsh high-potential conditions into a stable operating environment that actually protects the electrode from ion dissolution while maintaining high capacity utilization.

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 compound forms a stable SEI film with excellent oxidation resistance and flame retardancy, reducing battery swelling and improving storage and cycle characteristics at both low and high temperatures, particularly suitable for high-output batteries with high-nickel-based active materials.

Implementation Method 1

a compound represented by Formula 1 of the present disclosure includes a fluorine-substituted alkyl group with excellent oxidation resistance and flame retardancy as well as a propargyl group in its structure, a robust film containing a fluorine element may be formed on a surface of an electrode

Methodology Applied

Scientific EffectElectrochemical reaction:

Implementation Method 2

a non-aqueous electrolyte capable of forming an electrode-electrolyte interface with low resistance and high flame retardancy and high-temperature durability may be provided

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Data Source

PatentUS20240204249A1Additive for non-aqueous electrolyte, and non-aqueous electrolyte and lithium secondary battery which include the same

Publication Date: 2024.06.20 LG ENERGY SOLUTION LTD

AI summary

The present disclosure relates to an additive for a non-aqueous electrolyte, which includes a compound represented by Formula 1 capable of improving life characteristics of a lithium secondary battery by forming a stable and low-resistance electrode-electrolyte interface even at a high temperature, and a non-aqueous electrolyte and a lithium secondary battery which include the same.