Fluorinated Electrolyte Additives for High-Voltage Li-Ion Interface Stability
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Solution Overview
Problem
Existing lithium-ion batteries face challenges with high-voltage resistance, high-temperature stability, and interface stability due to the degradation of fluorinated solvents at the electrode-electrolyte interface, leading to issues like battery gas generation, capacity loss, and increased direct current resistance.
Innovation Solution
The use of a fluorinated solvent electrolyte system combined with 1-propene 1,3-sultone (PST) and diethyl (thiophen-2-ylmethyl)phosphonate (DTYP) additives forms a stable protective film at the electrode-electrolyte interface, enhancing high-temperature stability and reducing direct current resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fluorinated solvent is used in electrolyte to improve high-voltage resistance, then high-voltage stability is improved, but interface stability at high temperature deteriorates due to solvent degradation
Solution Approach 1:
The patent introduces PST and DTYP additives as intermediary substances that mediate between the fluorinated solvent and electrode interface. These additives preferentially react at the interface to form protective films, preventing direct contact and harmful reactions between the fluorinated solvent and electrode, thus resolving the contradiction between high-voltage resistance and interface stability.
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by introducing specific additives (PST and DTYP) in controlled amounts (0.01-1% mass ratio). This parameter change transforms the electrolyte system from one that degrades at high temperature to one that forms stable protective interfaces, while maintaining high-voltage resistance properties.
2Use of energy by moving object
If battery voltage is increased to improve energy density, then energy density is improved, but high-temperature stability deteriorates
Solution Approach 1:
The PST and DTYP additives serve as intermediary protective layers at the electrode-electrolyte interface, enabling the battery to operate at higher voltages (improving energy density) without suffering from high-temperature degradation. The additives absorb the thermal stress and prevent direct harmful interactions.
Solution Approach 2:
The patent creates a composite electrolyte system combining fluorinated solvent with PST and DTYP additives. This composite formulation achieves both high voltage tolerance (for energy density) and high-temperature stability, resolving the contradiction between these two performance parameters.
3Reliability
If conventional electrolyte additives are used to form protective film, then interface protection is improved, but direct current resistance increases
Solution Approach 1:
The patent changes the chemical structure parameters of the additives by selecting PST (1-propene sultone) and DTYP (diethyl thiophenylmethyl phosphonate) with specific functional groups. These structural parameters enable the formation of protective films with lower resistance compared to conventional additives, simultaneously achieving interface protection and maintaining low direct current resistance.
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 the high-temperature stability and cycling performance of high-voltage lithium-ion batteries by forming a stable protective film, reducing gas generation and capacity loss, and maintaining efficient lithium-ion transmission.
Implementation Method 1
the fluorinated solvent is combined with the PST as the additive and DTYP as the additive, a stable protective film may be formed at the interface between electrode and electrolyte
Data Source
AI summary
Disclosed is an electrolyte, which includes: a solvent, the solvent being a fluorinated solvent; a lithium salt; and additives, the additives including 1-propene 1,3-sultone (PST), and diethyl (thiophen-2-ylmethyl)phosphonate (DTYP). The electrolyte provided may withstand high voltage, and the electrolyte may form a stable protective film at the interface between the electrode and the electrolyte in the battery, ensuring the stability of the interface between electrode and electrolyte at high temperature, thereby significantly improving the high-temperature stability of high-voltage batteries. According to other embodiment of the present disclosure, a lithium-ion battery is also disclosed.