Nitrile-Based Battery Electrolyte for High-Voltage Stability

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Solution Overview

Problem

Lithium secondary batteries face challenges with the degradation of electrolytic solutions at high voltage and temperature, leading to performance deterioration, reduced lifespan, and safety concerns due to the formation of degradation products like HF and PF5.

Innovation Solution

The use of an electrolyte with an additive represented by Formula 1, which includes a nitrile-based compound, enhances oxidation resistance and inhibits side reactions, thereby stabilizing the electrolyte even at high voltage and temperature conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high voltage range is used to increase energy density, then battery capacity is improved, but electrolytic solution is oxidized causing performance deterioration

Engineering Contradiction:

Improvebattery capacityVSAvoidelectrolytic solution stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A film-forming additive is introduced as an intermediary substance between the electrolytic solution and the positive electrode. This additive preferentially reacts with oxidation products to form a protective film on the electrode surface, preventing direct contact and further oxidation of the electrolytic solution, thus resolving the contradiction between high voltage operation and electrolyte stability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The oxidation products that would normally harm the electrolytic solution are converted into beneficial protective films through the additive. The harmful oxidation reaction is redirected to form a stable interface layer that actually protects the electrolyte from further degradation, turning the harmful effect into a protective mechanism

Inventive Principle:

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

2Reliability

If LiPF6 is used as lithium salt to achieve high conductivity, then battery performance is improved, but degradation products HF and PF5 are generated causing safety deterioration

Engineering Contradiction:

Improvebattery performanceVSAvoidHF and PF5 generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The degradation products HF and PF5 that would normally harm the battery are converted into beneficial components of the protective film. The additive reacts with these harmful substances to form stable compounds that become part of the protective interface layer, eliminating their harmful effects while maintaining battery performance

Inventive Principle:

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

Solution Approach 2:

The film-forming additive acts as an intermediary that captures and neutralizes HF and PF5 before they can cause harm. It provides an alternative reaction pathway that converts these harmful degradation products into stable film components, protecting the electrolytic solution and improving safety

Inventive Principle:

Principle #24Intermediary (Mediator)

3Power

If high temperature operation occurs to increase reaction rates, then battery power is improved, but side reactions are accelerated causing lifespan reduction

Engineering Contradiction:

Improvebattery powerVSAvoidbattery lifespan

Core Design Contradiction:

PowerVSDuration of action of stationary object

Solution Approach 1:

The side reaction products that would normally reduce battery lifespan are converted into protective film components. The additive reacts with oxidation products at high temperature to form a stable interface layer that prevents further degradation reactions, allowing high power operation without sacrificing lifespan

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 proposed electrolyte solution improves the lifespan and high-temperature performance of lithium secondary batteries by reducing HF concentration and maintaining stability, thus enhancing the battery's overall performance and safety.

Implementation Method 1

enhances oxidation resistance and inhibits side reactions, thereby stabilizing the electrolyte even at high voltage and temperature conditions

Methodology Applied

Scientific EffectOxidation resistance: Oxidation

Implementation Method 2

inhibiting degradation of an electrolytic solution and reducing side reactions caused by oxidation of the electrolytic solution occurring on the surface of a positive electrode

Methodology Applied

Scientific EffectSide reactions inhibition:

Data Source

PatentUS20250174719A1Electrolyte for lithium secondary battery, and lithium secondary battery including the same

Publication Date: 2025.05.29 SAMSUNG SDI CO LTD

AI summary

An electrolyte for a lithium secondary battery including an additive represented by Formula 1, and a lithium secondary battery including a negative electrode, a positive electrode, and the electrolyte between the positive electrode and the negative electrode are provided.In Formula 1, A represents a chemical bond or —(CH2)k— (wherein k is an integer from 1 to 3), a and b are each independently 0 or an integer from 1 to 3, and a and b are not both integers from 1 to 3 simultaneously, and R, R1, R2, and R3 are each independently hydrogen, a C1-C10 alkyl group, or F.