Amide-Based Battery Electrolyte for Stable SEI and Dendrite Suppression
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Solution Overview
Problem
Lithium metal batteries face instability and low electrochemical performance due to the use of carbonate-based electrolytes, which lead to lithium dendrite formation and high costs associated with highly concentrated ether-based electrolytes, which are also flammable and have poor thermal stability.
Innovation Solution
An amide-based electrolyte comprising a solvent with a specific structure and a salt concentration range, which eliminates the need for fluorinated co-solvents, enhancing stability and ionic conductivity while being non-flammable and cost-effective.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbonate based electrolyte is used, then the electrolyte is well-developed and stable for lithium ion batteries, but it is unstable to lithium metal and causes lithium dendrite formation
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing amide-based solvents (N-methylformamide, N-ethylformamide, N,N-dimethylformamide, N,N-diethylformamide) with specific molecular structures and ratios, replacing traditional carbonate-based electrolytes to achieve both lithium metal stability and dendrite prevention
Solution Approach 2:
The patent creates a composite electrolyte system combining multiple amide-based solvents with specific lithium salts (LiFSO3, LiBF4, LiPF6) in optimized concentrations, forming a synergistic composition that provides both stability and dendrite suppression without requiring highly concentrated or fluorinated additives
2Reliability
If highly concentrated or locally concentrated electrolyte is used, then lithium metal stability is improved, but cost increases and viscosity increases
Solution Approach 1:
The patent optimizes the concentration parameters of amide-based solvents and lithium salts to achieve effective lithium metal stability at moderate concentrations, avoiding the need for highly concentrated electrolytes while maintaining performance and reducing cost
3Reliability
If ether based electrolyte is used, then lithium metal stability is improved, but thermal stability decreases and flammability increases
Solution Approach 1:
The patent changes the chemical composition from ether-based to amide-based solvents, fundamentally altering the molecular structure parameters to achieve both lithium metal stability and improved thermal stability with reduced flammability
4Reliability
If fluorinated co-solvent is used, then electrolyte performance is improved, but cost increases
Solution Approach 1:
The patent changes the chemical composition parameters by using cost-effective amide-based solvents with optimized concentrations instead of expensive fluorinated co-solvents, achieving comparable or superior performance at lower cost
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 amide-based electrolyte provides improved stability, increased cycle life, and higher ionic conductivity, avoiding dendrite formation and ensuring safety with excellent performance at high voltages.
Implementation Method 1
the formed SEI film is more stable thereby prevent the electrolyte further reduced by anode
Implementation Method 2
An amide-based electrolyte comprising a solvent with a specific structure and a salt concentration range, which eliminates the need for fluorinated co-solvents, enhancing stability and ionic conductivity
Data Source
AI summary
The present invention provides an electrolyte for a secondary battery and a secondary battery including same. The electrolyte for a secondary battery comprises a solvent comprising a compound having a structure represented by Formula, wherein R is selected from H, F, CH3 and CF3; R′ and R″ are each independently selected from H, CH3, CH2CH3, CF3, CH2CF3 and CF2CH3; and wherein based on the total weight of the solvent, the amount of the compound represented by formula I ranges from 81 wt % to 99 wt %; or the amount of the compound represented by formula I ranges from 90 wt % to 99 wt % By using the electrolyte for a secondary battery and the secondary battery including same of the present invention, the formed SEI film is more stable thereby prevent the electrolyte further reduced by anode, and increased battery life and cycle stability could be achieved.