Triazole-Sulfone Electrolyte Additive for LiPF6 Stability
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in maintaining high cycle-life and stability, especially at high temperatures, due to electrolyte decomposition and acid production from lithium salts, leading to increased resistance and capacity loss.
Innovation Solution
An additive represented by Chemical Formula 1, containing a triazole group and sulfone group, is introduced into the electrolyte to stabilize LiPF6 and suppress decomposition, forming a protective film on electrodes and reducing gas generation and transition metal elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes with lithium salts are used, then ionic conductivity is achieved, but decomposition and acid production occur at high temperatures leading to increased resistance and capacity loss
Solution Approach 1:
The patent introduces a compound containing both triazole and sulfone groups as an intermediary substance that mediates between the lithium salt and the electrolyte solvent. This compound preferentially reacts with HF and other acids to form stable complexes, preventing direct attack on the electrolyte components and electrodes, thus resolving the contradiction between achieving ionic conductivity and preventing decomposition
Solution Approach 2:
The patent changes the chemical parameters of the electrolyte system by adding a multifunctional compound that modifies the chemical environment. The triazole group provides proton affinity to neutralize acids, while the sulfone group provides coordination ability to stabilize lithium ions and complex with HF, thereby changing the chemical stability parameters of the electrolyte system at high temperatures
2Use of energy by moving object
If LiPF6 is used as lithium salt, then high ionic conductivity is achieved, but HF production and resistance increase occur during storage and cycling
Solution Approach 1:
The patent converts the harmful HF produced by LiPF6 decomposition into a beneficial complex by introducing the sulfone group which has strong coordination ability. The sulfone oxygen atoms coordinate with HF to form stable complexes, transforming the harmful acid into a stabilized species that no longer causes damage to electrodes or electrolyte, thus converting harm into benefit
Solution Approach 2:
The triazole-sulfone compound acts as an intermediary that intercepts HF before it can attack the electrolyte or electrodes. The triazole nitrogen atoms provide proton affinity to neutralize HF, serving as a protective intermediary layer between the LiPF6 decomposition products and the sensitive battery components
3Power
If high temperature operation is enabled, then power output is improved, but capacity reduction and swelling increase
Solution Approach 1:
The patent changes the thermal stability parameters of the electrolyte system by adding the triazole-sulfone compound. The triazole group provides thermal stability through its aromatic structure and proton affinity, while the sulfone group provides thermal oxidation resistance, thereby enabling the electrolyte to maintain its composition stability at high temperatures required for high power output
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 additive enhances cycle-life characteristics and reduces resistance increase at high temperatures, improving battery performance and stability during storage and operation.
Implementation Method 1
forming a protective film on electrodes
Implementation Method 2
stabilize LiPF6 and suppress decomposition
Data Source
AI summary
An additive for an electrolyte, an electrolyte including the additive for a rechargeable lithium battery, and a rechargeable lithium battery including the electrolyte are provided. The additive may be represented by Chemical Formula 1, where at least one selected from A and B is a group represented by Chemical Formula A.