Secondary Battery Electrolyte for Lithium Metal Anodes
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Solution Overview
Problem
Conventional secondary batteries with metal lithium electrodes face issues of increased overvoltage and inadequate cycle characteristics due to dendrite generation and side reactions, limiting energy density and repeated charge-discharge performance.
Innovation Solution
A secondary battery design incorporating a metal lithium negative electrode, a sulfonyl group-containing lithium salt, a glyme-based solvent, and specific additives such as lithium bis(oxalate)borate, which suppresses overvoltage and enhances cycle characteristics by reducing peak voltage and improving ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional protective layers or additives are used to prevent dendrites and side reactions, then reliability is improved, but overvoltage increases causing energy density to decrease
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by using a specific glyme-based solvent system (dimethoxyethane, diethoxyethane, or diglyme) combined with lithium bis(oxalate)borate and specific additives (vinylene carbonate, fluoroethylene carbonate, or their mixtures). This parameter change optimizes the electrochemical window and reduces overvoltage while maintaining protective functions against dendrites and side reactions.
Solution Approach 2:
The patent employs a composite electrolyte formulation combining multiple components: glyme-based solvents, lithium bis(oxalate)borate salt, and specific cyclic carbonate additives. This composite approach creates synergistic effects where the combination of materials provides both protection against dendrites/side reactions and reduced overvoltage, resolving the contradiction between reliability and energy density.
2Reliability
If conventional protective layers or additives are used to prevent dendrites and side reactions, then reliability is improved, but overvoltage increases causing charge-discharge performance to deteriorate
Solution Approach 1:
The patent optimizes electrolyte parameters by selecting specific glyme-based solvents with appropriate molecular structures and combining them with lithium bis(oxalate)borate and controlled amounts of cyclic carbonate additives (0.1-10 wt%). This parameter optimization reduces peak voltage during charge-discharge cycles while maintaining the protective function against dendrites, thereby improving charge-discharge performance without sacrificing reliability.
Solution Approach 2:
The patent introduces specific cyclic carbonate compounds (vinylene carbonate, fluoroethylene carbonate, or their mixtures) as intermediary substances that mediate between the metal lithium electrode and the bulk electrolyte. These intermediaries form protective interfaces that prevent direct harmful reactions while maintaining good ionic conductivity, thus improving both reliability and productivity simultaneously.
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 proposed battery configuration effectively reduces overvoltage and improves cycle characteristics, leading to enhanced energy density and prolonged charge-discharge performance.
Implementation Method 1
the electrolytic solution includes: a sulfonyl group-containing lithium salt; a glyme-based solvent
Implementation Method 2
a secondary battery including a positive electrode, a negative electrode, and an electrolytic solution
Data Source
AI summary
A secondary battery is provided and including a positive electrode, a negative electrode, and an electrolytic solution, where the negative electrode is metal lithium, and the electrolytic solution contains a sulfonyl group-containing lithium salt; a glyme-based solvent; and a specific additive.