Fluorinated Sulfonate Additive for High-Temperature Battery Stability
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries using sulfonic acid ester-based additives experience capacity lowering and storage deterioration when left at high temperatures, leading to irreversible battery degradation.
Innovation Solution
A non-aqueous electrolyte comprising a sulfonate represented by the general formula (1) with a concentration of 0.001 wt % to 0.2 wt % based on the total mass, which includes alkali metal or alkaline earth metal sulfonates, is used to improve battery stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfonic acid ester-based additive is used to form protective film on electrode, then coating film-forming capability is improved, but battery capacity lowering and storage deterioration occur when left at high temperature
Solution Approach 1:
The patent changes the chemical structure parameters of the sulfonic acid ester by introducing fluorine atoms at specific positions (using compounds with formulas (1) and (2) where R1-R6 are specific combinations of H, F, and alkyl groups). This structural modification allows the additive to maintain protective film-forming capability while significantly improving storage stability at high temperatures, resolving the contradiction between film-forming capability and thermal stability.
Solution Approach 2:
The patent uses composite electrolyte formulations combining fluorinated sulfonic acid esters with specific carbonate solvents (cyclic and chain carbonates) and lithium salts. This composite approach creates a synergistic effect where the fluorinated additive provides both protective film formation and high-temperature stability, while the solvent system supports these functions without causing decomposition.
2Duration of action of stationary object
If sulfonic acid ester-based additive is used to improve cycle properties, then coating film formation is enhanced, but irreversible lowering of discharging capacity is accelerated
Solution Approach 1:
The patent modifies the molecular structure of the sulfonic acid ester by fluorine substitution at specific positions (formulas (1) and (2)), which changes the electrochemical behavior of the additive. This structural parameter change enables the formation of protective films with lower resistance and better ionic conductivity, improving cycle life while minimizing irreversible capacity loss through more efficient lithium ion transport.
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 specified sulfonate concentration range enhances charging and discharging efficiency and cycle properties, reducing battery capacity loss and improving storage stability in non-aqueous electrolyte secondary batteries.
Implementation Method 1
an electrolyte solvent or the supporting salt causes a decomposition reaction to form a coating film having a high resistance on the surface of the electrode
Implementation Method 2
a method for suppressing the decomposition reaction by forming a protective film on the surface of the electrode
Data Source
AI summary
The present invention relates to a non-aqueous electrolyte comprising a non-aqueous electrolyte solvent, a supporting salt, and a sulfonate represented by a predetermined formula, the non-aqueous electrolyte having a sulfonate concentration of 0.001 wt % or more and less than 0.2 wt % based on the total mass of the non-aqueous electrolyte.