Lithium Imidazolate Electrolyte Conductivity via Nitrile Solvents
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Solution Overview
Problem
Lithium-ion batteries using conventional electrolyte solvents like carbonates face limitations in ionic conductivity due to poor salt dissociation and high viscosity, especially for power-type batteries, which restricts their performance and safety, particularly in applications like passenger vehicles.
Innovation Solution
The use of nitrile or dinitrile solvents, such as propionitrile, significantly improves the ionic conductivity of lithium imidazolate salts by enhancing salt dissociation and reducing viscosity, allowing for a wider operating temperature range and improved battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional carbonate solvents are used in lithium-ion batteries, then good compromise between viscosity and dielectric constant is achieved, but ionic conductivity is too low for power-type batteries
Solution Approach 1:
The patent changes the solvent parameter from conventional carbonates to nitrile-based solvents (acetonitrile, propionitrile, butyronitrile). This parameter change fundamentally alters the solvent properties, achieving both low viscosity and high dielectric constant, thereby resolving the contradiction between viscosity-dielectric compromise and ionic conductivity for power-type battery applications.
2Adaptability or versatility
If LiPF6 salt is used, then many qualities required for electrolyte are achieved, but degradation occurs as hydrofluoric acid gas by reaction with water, posing safety problems
Solution Approach 1:
The patent replaces the vulnerable LiPF6 salt with lithium imidazolate salts that have inherent resistance to hydrolytic degradation. Although lithium imidazolate salts initially showed low conductivity in carbonate solvents, the combination with nitrile-based solvents activates their full potential, providing a more stable, long-lasting electrolyte system that eliminates the safety problems associated with HF generation from LiPF6 decomposition.
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 nitrile solvents increases ionic conductivity from 6 mS/cm to up to 12 mS/cm, enhancing the power performance and safety of lithium-ion batteries by improving salt dissociation and reducing viscosity, thus overcoming the limitations of conventional solvents.
Implementation Method 1
their use as an electrolyte salt for Li-batteries. ion. But this ionic conductivity measured in so-called classic electrolyte solvents, which are mixtures of carbonates, is too low for use in so-called power type batteries. The applicant has discovered that the use of propionitrile makes it possible to improve the ionic conductivity of these lithium salts.
Implementation Method 2
But this ionic conductivity measured in so-called classic electrolyte solvents, which are mixtures of carbonates, is too low for use in so-called power type batteries. The applicant has discovered that the use of propionitrile makes it possible to improve the ionic conductivity of these lithium salts.
Data Source
AI summary
The invention relates to a composition comprising at least one electrolyte based on lithium imidazolate salts and to the use of nitrile or dinitrile solvents to increase the ion conductivity of electrolyte based on lithium imidazolate salts. The invention also relates to the use of the electrolyte composition in Li-ion batteries.