Lithium Ion Battery Electrolyte Using Vitreous Eutectic Mixture
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Solution Overview
Problem
Lithium ion batteries face issues with the thermal instability, decomposition, and water management of LiPF6 salt solutions, as well as the performance limitations of ionic liquids, including low lithium ion transference numbers and cation accumulation at the electrolyte-electrode interface.
Innovation Solution
A binary vitreous eutectic mixture of lithium fluorosulfonimides as a salt and alkylsulfonamides or arylsulfonamides as a solvent, represented by the formula AxBy, is used as an electrolyte, providing a non-flammable and thermally stable option with improved lithium ion conductivity and reduced viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiPF6 salt solutions are used as electrolyte, then ionic conductivity is achieved, but thermal instability and decomposition occur
Solution Approach 1:
The patent changes the chemical composition parameters by replacing LiPF6 with lithium fluorosulfonimides and changing the solvent system to sulfonamides, which fundamentally alters the thermal stability characteristics while maintaining ionic conductivity
Solution Approach 2:
The patent creates a composite electrolyte system combining lithium fluorosulfonimide salts with sulfonamide solvents in specific ratios to form a vitreous eutectic mixture, achieving synergistic effects that provide both thermal stability and ionic conductivity
2Reliability
If ionic liquids are used as electrolyte, then thermal stability is improved, but lithium ion transference number decreases
Solution Approach 1:
The patent optimizes the composition parameters by selecting specific lithium fluorosulfonimide salts and sulfonamide solvents in controlled ratios, achieving a balance between thermal stability and lithium ion transference number that overcomes the limitations of conventional ionic liquids
3Reliability
If ionic liquids are used as electrolyte, then thermal stability is improved, but cation accumulation at interface occurs
Solution Approach 1:
The patent changes the chemical parameters by using lithium fluorosulfonimides with specific molecular structures and sulfonamide solvents that reduce cation size and improve mobility, preventing accumulation at the electrode interface while maintaining thermal stability
4Reliability
If traditional electrolytes are used, then ionic conductivity is achieved, but viscosity is high
Solution Approach 1:
The patent changes the physical parameters by creating a vitreous eutectic mixture with optimized composition ratios that lower the glass transition temperature and reduce viscosity, enabling faster ion transport while maintaining thermal stability
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 eutectic mixture offers enhanced ionic conductivity, thermal stability, and reduced viscosity, maintaining performance across a wide temperature range while avoiding the drawbacks of traditional LiPF6 and ionic liquid electrolytes.
Implementation Method 1
The electrolyte may be used in a lithium ion battery, where such electrolyte is generally non-flammable
Implementation Method 2
The letters x and y are the mole fractions of elements A and B, respectively. This eutectic mixture is a liquid at ambient temperature and has a glass transition temperature (Tg) of less than −50° C.
Data Source
AI summary
An electrolyte for a lithium ion battery includes a vitreous eutectic mixture represented by the formula AxBy, where A is a salt chosen from a lithium fluoroalkylsulfonimide or a lithium fluoroarylsulfonimide, B is a solvent chosen from an alkylsulfonamide or an arylsulfonamide, and x and y are the mole fractions of A and B, respectively.