Fluorinated Triazine Additives for Lithium Battery Electrolytes
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Solution Overview
Problem
Current lithium-ion batteries face challenges in achieving long cycle life, high capacity retention, and low resistance build-up during cycling, as well as storage stability, despite the use of various additives in electrolyte compositions.
Innovation Solution
An electrolyte composition containing at least one aprotic organic solvent, a conducting salt, and a compound of formula (I), where R1, R2, and R3 are independently H or C1-C20 hydrocarbon groups that may be unsubstituted or substituted with specific groups, including S(O)2F, is used to enhance electrochemical cell performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional additives are used in electrolyte compositions, then certain properties are improved, but capacity retention and cycling performance remain insufficient
Solution Approach 1:
The patent modifies the chemical structure of existing triazine-based additives by introducing fluorinated alkyl groups with specific chain lengths and branching patterns. This parameter change in molecular structure optimizes the additive's ability to form stable SEI films, thereby simultaneously improving capacity retention and cycling performance without compromising other electrolyte properties.
Solution Approach 2:
The invention creates a composite additive system by combining fluorinated triazine compounds with specific ratios of linear and branched alkyl chains. This composite molecular structure leverages the benefits of both linear chains (mobility) and branched chains (stability), resulting in superior electrochemical performance compared to conventional single-structure additives.
2Quantity of substance
If electrolyte composition is optimized for high capacity, then resistance build-up during cycling increases
Solution Approach 1:
The patent converts the potentially harmful resistance build-up during cycling into a beneficial effect by designing fluorinated triazine additives that form stable, low-resistance SEI films. The fluorinated groups specifically orient at the electrode interface, creating a protective layer that prevents further resistance increase while maintaining high ion conductivity, thus transforming the harmful resistance build-up into a stable, beneficial interface structure.
3Stability of the object's composition
If storage stability is improved through additive selection, then cycle life is limited
Solution Approach 1:
The fluorinated triazine compound serves multiple functions simultaneously: it provides storage stability by forming a stable SEI film during idle periods, and extends cycle life by maintaining interface integrity during repeated charging/discharging. The molecular structure with fluorinated alkyl groups and triazine core enables this multi-functionality, making the additive effective for both storage and cycling applications.
4Reliability
If film forming additives are used to protect electrodes, then electrochemical performance deteriorates
Solution Approach 1:
The patent applies local quality by concentrating the film-forming function specifically at the electrode interface where it is most needed, while maintaining high ion conductivity in the bulk electrolyte. The fluorinated triazine additive forms a thin, protective SEI film only at the electrode surface through preferential adsorption and reaction, leaving the bulk electrolyte composition optimized for high electrochemical performance and fast 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 proposed electrolyte composition improves capacity retention and cycling performance, providing better storage stability and extended cycle life for lithium-ion batteries.
Implementation Method 1
film forming additives which react during first charge/discharge cycle on the electrode surface thereby forming a film on the electrode
Implementation Method 2
organic carbonates, ethers, esters and ionic liquids are used as sufficiently polar solvents for solvating the conducting salt(s)
Data Source
AI summary
Heterocyclic sulfonyl fluoride additives for electrolyte composition for lithium batteries An electrolyte composition containing •(i) at least one aprotic organic solvent; •(ii) at least one conducting salt; •(iii) at least one compound of formula (I) wherein R1, R2, and R3 are each independently H or a C1-C20 hydrocarbon group which may be unsubstituted or substituted by one or more substituents selected from F, CN, OS(O)2F, and S(O)2F and which may contain one or more groups selected from —O—, —S—, —C(O)O—, —OC(O)—, and —OS(O)2—; wherein at least one of R1, R2, and R3 is substituted by one or more S(O)2F groups; and •(iv) optionally one or more additives.