Lithium Battery Electrolyte Additive for PF5 Capture and SEI Stability
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Solution Overview
Problem
Rechargeable lithium batteries face issues with cycle-life degradation, increased resistance, and gas generation due to acid attack from thermal decomposition of lithium salts, leading to capacity reduction and structural changes in electrodes, especially at high temperatures.
Innovation Solution
An additive represented by Chemical Formula 1, containing a triazole group and a sulfone group, is introduced into the electrolyte to capture PF5 and stabilize LiPF6, forming a protective film on electrodes, thereby preventing acid-induced degradation and enhancing the Solid Electrolyte Interface (SEI) film stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium salt is used in the electrolyte to enable ion conduction, then the battery can function, but thermal decomposition occurs at high temperatures producing acid that attacks electrodes and reduces cycle-life
Solution Approach 1:
The patent introduces a sulfone-containing compound as an intermediary substance that reacts with PF5 to form a complex, thereby eliminating the harmful acid attack on electrodes. This intermediary approach resolves the contradiction by providing a chemical mediator that neutralizes the decomposition products while maintaining electrolyte functionality
Solution Approach 2:
The patent converts the harmful thermal decomposition of lithium salts into a beneficial process by using the decomposition products (PF5) to form protective films on electrodes through controlled reaction with the sulfone-containing compound. The harmful acid attack is transformed into a protective mechanism that enhances electrode stability and extends cycle-life
2Reliability
If conventional electrolyte additives are used to improve performance, then some characteristics improve, but high temperature storage characteristics and resistance stability remain insufficient
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by introducing a sulfone-containing compound with specific molecular structure and properties. This parameter change enables the electrolyte to maintain stable resistance characteristics at high temperatures while improving overall storage performance, resolving the contradiction between reliability and compositional stability
3Power
If battery operation continues at high temperature, then power delivery is maintained, but gas generation increases and capacity reduces due to electrode degradation
Solution Approach 1:
The patent applies preliminary action by having the sulfone-containing compound proactively form protective films on electrode surfaces before significant degradation occurs. This preventive measure suppresses gas generation and capacity reduction during high-temperature operation while maintaining power delivery capabilities throughout the battery lifecycle
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 significantly improves cycle-life characteristics, suppresses resistance increase, and reduces gas generation, especially at high temperatures, resulting in enhanced battery performance and stability.
Implementation Method 1
An additive represented by Chemical Formula 1, containing a triazole group and a sulfone group, is introduced into the electrolyte to capture PF5 and stabilize LiPF6
Implementation Method 2
forming a protective film on electrodes, thereby preventing acid-induced degradation and enhancing the Solid Electrolyte Interface (SEI) film stability
Data Source
Figure 1
AI summary
Provided are an additive for an electrolyte represented by Chemical Formula 1 and an electrolyte for a rechargeable lithium battery and rechargeable lithium battery including the same. Details of the above Chemical Formula 1 are as described in the specification.