Non-Aqueous Electrolyte Additive for Stable SEI Film Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion secondary batteries face issues with fast-charging performance, cycle performance, and safety due to continuous decomposition of the electrolytic solution at the negative electrode during charging, necessitating the formation of a stable and uniform solid electrolyte interphase (SEI) film.
Innovation Solution
Incorporating a cyclic sulfate compound as an additive in the non-aqueous electrolytic solution to form a stable inorganic-organic mixed SEI film with stronger electron-blocking ability on the negative electrode, enhancing the film's mechanical strength and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytic solutions are used, then the battery can operate, but the electrolytic solution continuously decomposes at the negative electrode during charging, deteriorating battery life
Solution Approach 1:
The patent applies preliminary action by introducing a cyclic sulfate compound additive that proactively forms a stable SEI film on the negative electrode before extensive electrolyte decomposition occurs. This pre-formed protective layer prevents subsequent continuous decomposition, thereby extending battery life while maintaining operational functionality.
2Reliability
If an SEI film is formed on the negative electrode, then electrolytic solution decomposition is inhibited, but the SEI film must be uniform, dense, and stable to be effective
Solution Approach 1:
The patent applies parameter changes by carefully controlling the concentration of the cyclic sulfate compound additive (0.01-5 wt%) and optimizing the electrolyte composition ratios. These parameter adjustments ensure that the SEI film forms with uniform thickness, dense structure, and stable composition, achieving both reliability and manufacturing precision requirements.
3Object-generated harmful factors
If the SEI film has strong electron-blocking ability, then electrolytic solution decomposition is prevented, but the film must maintain good lithium ion conductivity
Solution Approach 1:
The patent applies composite materials by creating a composite SEI film structure through the cyclic sulfate compound that combines electron-blocking inorganic components with lithium ion-conductive organic components. This composite structure simultaneously achieves strong electron-blocking ability to prevent decomposition and maintains good lithium ion conductivity for reliable battery operation.
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 SEI film effectively prevents electrolytic solution decomposition, improving the cycle performance and life of the battery by reducing negative electrode resistance and promoting efficient film formation.
Implementation Method 1
the cyclic sulfate compound having general formula (I), when used as an additive in a non-aqueous electrolytic solution, generates a more stable inorganic-organic mixed SEI film with a stronger electron-blocking ability on the negative electrode side during the first charging process of the secondary battery
Implementation Method 2
The SEI film can block electrons and thus prevent the electrolytic solution from continuously decomposing at the negative electrode
Data Source
AI summary
Provided are a non-aqueous electrolyte, a secondary battery, and an electrical apparatus. The non-aqueous electrolyte comprises an additive, the additive comprising a cyclic sulfate ester compound having the structure shown in general formula (I), wherein R1, R2, R3, R4, R5, and R6 are each independently selected from any one of: a group having the structure shown in general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, where n1, n2 and n3 are each independently any integer 0-2.