Fluoroether Battery Electrolyte for Stable SEI and Cycle Life
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Solution Overview
Problem
Existing secondary battery electrolytes face challenges with high reactivity, leading to poor cycling and storage performances due to side reactions with metal negative electrodes, necessitating improved electrochemical stability and safety.
Innovation Solution
An electrolyte comprising a fluoroether solvent and additives such as ionic liquid, amide compound, and alloy additives is used to enhance interface stability, forming a stable SEI film and preventing side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If liquid electrolyte is used to provide excellent ion conductivity, then kinetic performance is improved, but reactivity with metal negative electrode increases leading to poor cycling performance
Solution Approach 1:
A protective film is formed on the metal negative electrode surface that acts as an intermediary layer. This film allows ion transport while blocking direct contact between the liquid electrolyte and the metal electrode, thereby preventing harmful side reactions while maintaining good ion conductivity.
Solution Approach 2:
The chemical composition and physical properties of the electrolyte are modified by adjusting the ratio of cyclic carbonate to chain carbonate, and by adding specific additives. These parameter changes reduce the reactivity of the electrolyte with the metal negative electrode while preserving ion conductivity.
2Reliability
If electrolyte composition is optimized to improve cycling performance, then interface stability is enhanced, but ion conductivity may be compromised
Solution Approach 1:
The electrolyte is designed as a composite system combining multiple components: cyclic carbonate, chain carbonate, and specific additives in optimized ratios. This composite approach allows the electrolyte to simultaneously achieve good ion conductivity and stable interface properties for improved cycling performance.
Solution Approach 2:
The proportions of different electrolyte components are precisely controlled within specific ranges. The cyclic carbonate content is maintained at 60-95 vol%, chain carbonate at 5-40 vol%, with additives at 0.1-10 vol%. These parameter optimizations balance ion conductivity and interface 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 solution significantly improves cycling and storage stability of secondary batteries by stabilizing the interface, reducing side reactions, and enhancing safety.
Implementation Method 1
the fluoroether solvent is obtained by directly substituting hydrogen bonded to carbon of the corresponding ether molecules with fluorine
Implementation Method 2
forming a stable SEI film and preventing side reactions
Implementation Method 3
The electrolyte serves as a medium for ion transfer between the positive and negative electrodes
Data Source
AI summary
This application provides an electrolyte for secondary battery, a secondary battery, a battery module, a battery pack, and an electric apparatus. The electrolyte for secondary battery includes a fluoroether solvent and an additive, where the additive includes one or more of ionic liquid additive, amide compound additive, cation shielding additive, and alloy additive. In this application, with one or more of ionic liquid additive, amide compound additive, cation shielding additive, and alloy additive added in an electrolyte containing the fluoroether solvent, interface stability of the secondary battery is significantly enhanced, and the cycling performance, storage stability, and overall safety of the secondary battery are improved.