Aromatic Amine Electrolyte Additive for High Voltage Lithium Battery

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Solution Overview

Problem

Conventional electrolytes for lithium rechargeable batteries, particularly those using LiPF6 as a lithium salt, decompose at high temperatures with spinel-type positive active materials like manganese-based lithium oxide, leading to metal ion elution and deposition on the negative electrode, causing increased negative electrode potential, reduced open circuit voltage, and deteriorated cycle performance.

Innovation Solution

Incorporating an aromatic amine, such as a pyridine derivative, into the electrolyte to neutralize hydrogen fluoride (HF) generated by lithium salt decomposition, thereby preventing metal ion elution and forming a membrane on the positive electrode surface to maintain high voltage and improve high-temperature storage characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If LiPF6 is used as lithium salt in conventional electrolyte, then high voltage operation is enabled, but metal ion elution occurs at high temperature leading to deteriorated cycle performance

Engineering Contradiction:

ImprovevoltageVSAvoidcycle performance

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

Aromatic amine acts as an intermediary substance between LiPF6 and metal ions. It captures HF generated from LiPF6 decomposition, preventing HF from attacking the spinel-type positive active material and causing metal ion elution. This mediator approach resolves the contradiction by enabling high voltage operation while preventing the harmful side effects at high temperature.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the harmful HF generated from LiPF6 decomposition into a beneficial effect. Instead of allowing HF to cause metal ion elution, the aromatic amine captures HF to form stable complexes, transforming a harmful byproduct into a controlled intermediate that ultimately protects the electrode material and improves cycle performance.

Inventive Principle:

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

2Temperature

If LiPF6 decomposes at high temperature, then HF is generated, but metal ion elution and deposition on negative electrode occur causing increased negative electrode potential

Engineering Contradiction:

Improvehigh temperature storageVSAvoidmetal ion elution

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The aromatic amine captures the harmful HF generated from LiPF6 decomposition at high temperature, converting it into a stable complex. This prevents HF from attacking the spinel-type positive active material and causing metal ion elution, thereby transforming a harmful high-temperature side reaction into a controlled process that protects electrode integrity.

Inventive Principle:

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

Solution Approach 2:

Aromatic amine serves as a chemical intermediary that intercepts HF before it can react with the positive active material. This mediator approach allows the system to operate at high temperatures without suffering from metal ion elution, as the aromatic amine absorbs the harmful HF and prevents it from reaching the electrode material.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Power

If conventional electrolyte is used, then high voltage operation is possible, but open circuit voltage reduces due to metal ion deposition

Engineering Contradiction:

ImprovevoltageVSAvoidopen circuit voltage reduction

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The aromatic amine captures HF that would otherwise cause metal ion elution and subsequent deposition on the negative electrode. By converting HF into a stable complex, the invention prevents the formation of insulating layers and metal deposits that reduce open circuit voltage, thereby maintaining high voltage operation throughout the battery's lifecycle.

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 use of aromatic amines in the electrolyte significantly enhances the high voltage lithium rechargeable battery's cycle life and high-temperature storage characteristics by suppressing metal ion elution and maintaining open circuit voltage, resulting in improved battery performance at elevated temperatures.

Implementation Method 1

an aromatic amine to neutralize HF generated by decomposition of a lithium salt dissolved in the electrolyte

Methodology Applied

Scientific EffectNeutralization:

Implementation Method 2

suppressing the metal ions from depositing on a positive electrode surface by forming a membrane on the positive electrode surface

Methodology Applied

Scientific EffectFilm formation: Coatings

Data Source

PatentUS9276291B2Electrolyte for high voltage lithium rechargeable battery and lithium rechargeable battery comprising the same

Publication Date: 2016.03.01 SAMSUNG SDI CO LTD

AI summary

In an aspect, an electrolyte for a lithium rechargeable battery and a lithium rechargeable battery are provided. The electrolyte may include a non-aqueous organic solvent, a lithium salt, and an aromatic amine as an additive.