Sulfone-Based Electrolyte for Lithium Metal Anodes
Solution Overview
Problem
Lithium metal anodes in batteries face challenges with unstable solid electrolyte interfaces (SEIs) due to dendrite growth and rapid electrolyte degradation, leading to low coulombic efficiency and reduced cycle life, especially in high-energy rechargeable batteries like lithium-ion and lithium-sulfur batteries.
Innovation Solution
Development of non-aqueous electrolytes containing Group 1 salts dissolved in mixtures of sulfone, sultone, and sulfonamide compounds, which support high coulombic efficiency and ionic conductivity, and exhibit improved oxidative stability, forming uniform and self-healing SEIs that resist cracking and lithium polysulfide shuttle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional electrolytes are used with lithium metal anodes, then high energy density can be achieved, but the solid electrolyte interface becomes unstable due to dendrite growth and rapid electrolyte degradation
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by using a specific mixture of cyclic carbonate (15-30 vol%), linear carbonate (40-70 vol%), and cyclic carboxylate (10-30 vol%). This parameter optimization resolves the contradiction by achieving both high energy density and stable SEI formation, preventing dendrite growth while maintaining high lithium plating/stripping efficiency of at least 80%.
2Quantity of substance
If high energy rechargeable batteries are developed, then increased battery life and energy capacity are achieved, but coulombic efficiency and cycle life are reduced due to electrolyte degradation
Solution Approach 1:
The patent employs a composite electrolyte system combining three different types of solvents (cyclic carbonate, linear carbonate, and cyclic carboxylate) in optimized proportions. This composite approach creates synergistic effects where each component contributes specific properties: cyclic carbonate provides high dielectric constant for salt dissolution, linear carbonate provides low viscosity for ionic conductivity, and cyclic carboxylate enhances SEI stability. The resulting composite electrolyte achieves both high energy capacity and sustained coulombic efficiency of at least 80% over extended cycling.
3Use of energy by moving object
If lithium metal anodes are used to increase energy density, then battery energy capacity increases, but dendrite growth and electrolyte degradation occur leading to reduced cycle life
Solution Approach 1:
The patent introduces a carefully balanced electrolyte composition as an intermediary between the lithium metal anode and the rest of the battery system. The specific mixture of cyclic carbonate, linear carbonate, and cyclic carboxylate acts as a mediator that facilitates smooth lithium ion transport while preventing direct harmful interactions between lithium metal and the electrolyte. This intermediary electrolyte layer promotes uniform lithium deposition, prevents dendrite formation, and maintains cycle life while enabling high energy capacity from lithium metal anodes.
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 novel sulfone-based electrolytes enhance coulombic efficiency to at least 80%, increase ionic conductivity, and maintain stability up to 5 V vs Li/L+, significantly improving the cycle life and energy density of lithium metal batteries.
Implementation Method 1
a Group 1 salt dissolved in a mixture of at least two sulfone compounds, a mixture of a sulfone compound and a sultone compound, or a mixture of a sulfone compound and a sulfonamide compound
Implementation Method 2
a non-aqueous electrolyte supports a coulombic efficiency, with respect to plating and stripping of lithium, of at least 80%
Data Source
AI summary
A non-aqueous electrolyte, with a coulombic efficiency with respect to lithium of at least 80%, that includes a Group 1 salt dissolved in a mixture containing two sulfone compounds, a mixture containing a sulfone compound and a sultone compound, and/or a mixture containing a sulfone compound and a sulfonamide compound. The Group 1 salt can be a lithium salt, the sulfone compound can be a cyclic sulfone such as thietane-1,1-dioxide and sulfolane, the sultone compound can be a cyclic sultone such as 1,3-propane sultone, and the sulfonamide compound can be a partially fluorinated sulfonamide such as 1,1,1-trifluoro-N,N-dimethylmethanesulfonamide and N-butyl-1,1,1-trifluoro-N-methylmethanesulfonamide. Additives such as another lithium salt, a polyunsaturated compound, a cyclic anhydride, a cyclic unsaturated sultone, and/or a cyclic phosphate can be included in the non-aqueous electrolyte.