Cyclopropanecarbonitrile Electrolyte for Battery Reliability

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Solution Overview

Problem

Conventional non-aqueous electrolyte solutions for batteries face issues with low ionic conductivity and reliability due to degradation of carbonate solvents and low SEI-forming ability of nitrile solvents, leading to reduced discharge efficiency and battery performance.

Innovation Solution

An electrolyte solution containing cyclopropanecarbonitrile as a non-aqueous solvent with an alkali metal salt, which enhances ionic conductivity and stability by suppressing continuous reductive degradation, allowing for high input-output characteristics and reliability through its high polarity and ability to dissolve alkali metal salts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbonate solvent is used in non-aqueous electrolyte solution, then reliability is improved through high SEI-forming ability, but ionic conductivity deteriorates due to continuous reductive degradation

Engineering Contradiction:

Improvebattery reliabilityVSAvoidionic conductivity

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the chemical structure parameter of the nitrile compound by introducing a cyclopropane ring structure. This structural modification alters the electrochemical properties, enabling the formation of a stable SEI film that prevents continuous degradation while maintaining high ionic conductivity, thus resolving the contradiction between reliability and ionic conductivity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite electrolyte system by combining cyclopropanecarbonitrile with other carbonate solvents (cyclic and/or linear). This composite approach leverages the complementary properties of each component: cyclopropanecarbonitrile provides stable SEI formation, while the carbonate solvents contribute to high ionic conductivity, achieving both reliability and performance.

Inventive Principle:

Principle #40Composite materials

2Loss of substance

If nitrile solvent is used in non-aqueous electrolyte solution, then ionic conductivity is improved, but reliability deteriorates due to low SEI-forming ability and continuous degradation

Engineering Contradiction:

Improveionic conductivityVSAvoiddischarge efficiency

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The patent modifies the nitrile solvent by incorporating a cyclopropane ring structure, which fundamentally changes its electrochemical behavior. This structural parameter change enables the formation of a stable SEI film on the electrode surface, preventing continuous reductive degradation and improving reliability while preserving the high ionic conductivity inherent to nitrile solvents.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional electrolyte solution is used, then manufacturing simplicity is maintained, but input-output characteristics and reliability deteriorate

Engineering Contradiction:

Improveelectrolyte solution preparationVSAvoidinput-output characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the chemical composition parameter by specifying cyclopropanecarbonitrile and its derivatives as the nitrile compound component. This parameter change delivers superior input-output characteristics and reliability while maintaining ease of manufacture, as the compound can be directly used in electrolyte formulation without complex processing steps.

Inventive Principle:

Principle #35Parameter changes

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 cyclopropanecarbonitrile in the electrolyte solution increases ionic conductivity and reliability, resulting in batteries with improved input-output characteristics and enhanced energy density, while minimizing degradation and maintaining high-molecular-weight compounds that form a stable SEI, thus extending battery life.

Implementation Method 1

nitrile groups have high polarity. Therefore, the nitrile groups have high coordination ability to alkali metal ions such as a lithium ion. Therefore, nitrile compounds have the high ability to dissolve alkali metal salts such as lithium salts.

Methodology Applied

Scientific EffectSolvation: Solvation

Implementation Method 2

A carbonate solvent used in conventional techniques undergoes one-electron reduction on a negative electrode and therefore is degraded. In this reaction, a degradation product of the carbonate solvent forms a passive film called a solid electrolyte interface (SEI).

Methodology Applied

Scientific EffectReduction: Reduction

Data Source

PatentUS9929431B2Electrolyte solution and battery

Publication Date: 2018.03.27 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

An electrolyte solution contains a non-aqueous solvent and an alkali metal salt dissolved in the non-aqueous solvent. The non-aqueous solvent contains cyclopropanecarbonitrile. A battery includes an electrolyte solution which contains a non-aqueous solvent containing cyclopropanecarbonitrile and an alkali metal salt dissolved in the non-aqueous solvent, a positive electrode containing a positive electrode active material that has a property of occluding and releasing an alkali metal ion, and a negative electrode containing an alkali metal or a negative electrode active material that has a property of occluding and releasing the alkali metal ion.