Boron Cluster Electrolytes for Low-Overpotential Reactive Anodes
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Solution Overview
Problem
Liquid electrolytes with lithium bis(fluorosulfonyl)imide (LiFSI) salts in ether and/or ester solvents exhibit higher than desired resistance to ionic mobility and metal plating and stripping issues with anodes.
Innovation Solution
The use of electrolytes comprising metal cations such as Li+, Na+, Mg2+, Ca2+, or Zn2+, boron cluster anions, and solvent mixtures including aromatic compounds like benzene derivatives, which enhance ionic conductivity and reduce metal plating/stripping overpotentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiFSI salts in ether and/or ester solvents are used, then the electrolyte performs well in batteries with lithium metal anodes, but it exhibits higher than desired resistance to ionic mobility and metal plating and stripping
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by replacing LiFSI salts with alternative lithium salts (LiClO4, LiBF4, LiPF6) and modifying the solvent composition by adding cyclic carbonic esters (EC, PC) to the ether/ester solvent system. These parameter changes reduce the resistance to ionic mobility and improve metal plating and stripping performance while maintaining battery reliability with lithium metal anodes.
Solution Approach 2:
The patent creates a composite electrolyte system by combining multiple solvent types (ether, ester, and cyclic carbonic ester) and multiple salt types. This composite approach synergistically improves ionic mobility and metal plating/stripping performance while maintaining compatibility with lithium metal anodes, resolving the contradiction between reliability and harmful resistance.
2Device complexity
If traditional LiFSI-based electrolytes are used, then the electrolyte structure is simple, but the coulombic efficiency is lower and metal plating/stripping overpotentials are higher
Solution Approach 1:
The patent modifies the electrolyte composition parameters by introducing cyclic carbonic esters and alternative lithium salts, which changes the electrochemical properties of the system. This results in higher coulombic efficiency and lower metal plating/stripping overpotentials, improving productivity despite the increased compositional complexity.
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 electrolytes achieve high coulombic efficiencies and reduced metal plating/stripping overpotentials, particularly with reactive anodes and current collectors, outperforming traditional LiFSI-based electrolytes.
Implementation Method 1
Liquid electrolytes with lithium bis(fluorosulfonyl)imide (LiFSI) salts in ether and/or esters solvents have been reported to perform well in batteries with lithium metal anodes
Implementation Method 2
metal plating and metal stripping of the anode
Implementation Method 3
metal plating and stripping issues with anodes
Data Source
AI summary
An electrolyte includes a metal cation selected from Li+, Na+, Mg2+, Ca2+, and/or Zn2+, a boron cluster anion, and a solvent mixture that includes an aromatic compound and at least one solvent. The aromatic compound can include benzene, toluene, o-xylene, m-xylene, p-xylene, mesitylene, hexamethylbenzene, biphenyl, naphthalene, and a compounds with partial or full substitutions of hydrogen with fluorine for these aromatic compounds. And the at least one solvent can include an ether solvent, an ester solvent, a sulfone solvent, a carbonate solvent, poly(ethylene oxide), an ionic liquid, a nitrile solvent, and/or combinations thereof.