Non-Aqueous Electrolyte Additive for High-Ni Battery Passivation

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Solution Overview

Problem

Lithium secondary batteries face performance degradation due to gas generation and transition metal elution at high temperatures, leading to reduced durability and capacity retention, especially with high-Ni-based positive electrodes.

Innovation Solution

A non-aqueous electrolyte solution for lithium secondary batteries incorporating a compound with a propargyl, phosphite, and carbonate group, which forms stable passivation films on electrodes, preventing transition metal elution and side reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a high-Ni-based positive electrode is used to increase capacity, then energy density is improved, but gas generation increases due to carbonate solvent decomposition

Engineering Contradiction:

Improveenergy densityVSAvoidgas generation

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a fluorinated cyclic carbonate compound as an intermediary substance that mediates between the high-Ni positive electrode and the carbonate solvent. This compound preferentially decomposes to form a protective fluorinated film on the electrode surface, acting as a barrier that prevents direct contact and harmful reactions between the carbonate solvent and the reactive high-Ni electrode, thereby suppressing gas generation while maintaining high capacity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical composition parameters of the electrolyte by incorporating fluorinated cyclic carbonate compounds with specific molecular structures (containing F atoms and cyclic carbonate groups). This parameter change in the electrolyte composition alters the decomposition behavior at the electrode interface, forming more stable protective films that reduce gas evolution during charging and discharging cycles

Inventive Principle:

Principle #35Parameter changes

2Reliability

If Lewis acids such as HF are formed by electrolyte salt decomposition, then ionic conductivity is improved, but transition metal elution increases causing capacity degradation

Engineering Contradiction:

Improveionic conductivityVSAvoidtransition metal elution

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent converts the harmful effect of Lewis acids into a beneficial protective mechanism. The fluorinated cyclic carbonate compound reacts with Lewis acids (such as HF) to form stable fluorinated protective films on the electrode surfaces. This transformation turns the previously harmful Lewis acid decomposition products into useful film-forming agents that prevent transition metal elution while maintaining ionic conductivity through the passivation film

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If passivation films are formed on electrode surfaces to prevent transition metal elution, then capacity retention is improved, but film formation consumes electrolyte and increases resistance

Engineering Contradiction:

Improvecapacity retentionVSAvoidelectrolyte consumption

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent employs fluorinated cyclic carbonate compounds as sacrificial additives that are intentionally designed to be consumed during initial cycles. These compounds preferentially decompose to form stable protective films, sacrificing themselves in the process. This disposable approach ensures that the main electrolyte solvent is preserved from decomposition, and the formed films provide long-term protection against transition metal elution, improving capacity retention despite the initial consumable loss

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 enhances high-temperature storage and cycle characteristics by forming robust passivation films, reducing resistance and capacity degradation, and improving battery durability.

Implementation Method 1

a compound represented by Formula (1) as an additive... contains a functional group such as a propargyl group and a carbonate group (—OC(═O)O—) that is easily reduced on the surface of the negative electrode

Methodology Applied

Scientific EffectElectrochemical reduction: Reduction

Data Source

PatentUS20240162490A1Non-Aqueous Electrolyte Solution for Lithium Secondary Battery and Lithium Secondary Battery Including the Same

Publication Date: 2024.05.16 LG ENERGY SOLUTION LTD

AI summary

A non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery having improved high temperature durability by including the same is described herein. Specifically, the non-aqueous electrolyte solution may comprise a lithium salt, a non-aqueous organic solvent and a compound represented by Formula 1 as an additive:wherein R is described herein.