Non-Aqueous Battery Electrolyte Additive for Lewis Acid Scavenging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face degradation due to the formation of Lewis acid by-products like HF and PF5, which cause metal ion elution, increased resistance, and potential internal short circuits, necessitating an electrolyte solution that can scavenging these by-products and form a stable film on the electrode surface.
Innovation Solution
A non-aqueous electrolyte solution for lithium secondary batteries containing a compound with a 5- or 6-membered nitrogen-containing ring and a phosphoryl group as an additive, which scavenges Lewis acid by-products and forms a solid film on the electrode surface to prevent metal ion elution and improve high-temperature storage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiPF6 is used as the lithium salt, then high ionic conductivity is achieved, but Lewis acid by-products (HF, PF5) are generated through thermal decomposition
Solution Approach 1:
The patent introduces a nitrogen-containing cyclic compound as an intermediary substance that reacts with Lewis acid by-products (HF, PF5) to form stable complexes. This mediator prevents the harmful by-products from attacking the electrode passivation films while allowing LiPF6 to maintain high ionic conductivity in the electrolyte solution.
Solution Approach 2:
The patent converts the harmful Lewis acid by-products into beneficial stable complexes through chemical reaction with the nitrogen-containing additive. The previously harmful HF and PF5 are transformed into stable adducts that no longer attack the electrode surfaces, thereby eliminating their harmful effects while maintaining the electrochemical performance of LiPF6.
2Quantity of substance
If transition metal ions are eluted from the positive electrode, then battery capacity is maintained initially, but decomposition of electrolyte solvent accelerates causing gas generation and resistance increase
Solution Approach 1:
The nitrogen-containing cyclic compound acts as a protective intermediary that binds to eluted transition metal ions, preventing them from catalyzing the decomposition of the electrolyte solvent. This intermediary mechanism stops the chain reaction that would otherwise lead to gas generation and increased resistance.
Solution Approach 2:
The patent employs the nitrogen-containing additive as a preemptive protective agent that is present in the electrolyte before metal ion elution occurs. This additive provides beforehand cushioning by being ready to complex with any metal ions that may be released, preventing them from attacking the electrolyte solvent and causing harmful side reactions.
3Loss of substance
If transition metal ions are re-deposited on the positive electrode, then material is recovered, but resistance of the positive electrode increases
Solution Approach 1:
The nitrogen-containing cyclic compound serves as a mediating agent that forms soluble complexes with transition metal ions, preventing their re-deposition on the positive electrode surface. This intermediary complexation keeps metal ions in solution without allowing them to accumulate on the electrode, thereby preventing resistance increase.
4Quantity of substance
If metal ions are transferred to and deposited on the negative electrode, then charge balance is maintained, but self-discharging occurs and SEI film is destroyed
Solution Approach 1:
The nitrogen-containing additive acts as a protective intermediary that binds to metal ions in the electrolyte, preventing their transfer and deposition on the negative electrode. This intermediary mechanism stops the metal ions from destroying the SEI film and causing self-discharging, while still allowing charge balance to be maintained through normal lithium ion transport.
Solution Approach 2:
The patent uses the nitrogen-containing compound as a preemptive protective layer in the electrolyte that is ready to complex with metal ions before they can reach the negative electrode. This beforehand cushioning prevents the harmful interactions between metal ions and the SEI film, protecting the negative electrode from degradation.
5Quantity of substance
If dendrites form on the negative electrode, then metal ion deposition is achieved, but internal short circuit occurs reducing battery safety
Solution Approach 1:
The nitrogen-containing cyclic compound serves as a mediating substance that uniformly distributes metal ions in the electrolyte through complexation, preventing localized concentration gradients that lead to dendrite formation. This intermediary mechanism ensures smooth metal ion deposition without dendritic growth, thereby preventing internal short circuits.
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 effectively removes Lewis acid by-products, reducing battery deterioration, improving cycle characteristics and high-temperature safety by suppressing side reactions and forming a stable film on the electrodes.
Implementation Method 1
the first additive includes a compound represented by the following Formula 1... Ar is a 5-membered or 6-membered nitrogen-containing ring... effectively removing Lewis acid by-products, which are the by-products of electrolyte salts
Implementation Method 2
forming a stable film on the electrode surface... has the effects of suppressing the elution of metals by forming a solid SEI
Data Source
AI summary
Provided are a non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery including the same and having improved high-temperature storage characteristics and high-temperature cycle characteristics. Specifically, the non-aqueous electrolyte solution may comprise a lithium salt, an organic solvent and a compound represented by Formula 1 as a first additive:wherein Formula 1,Ar is a 5-membered or 6-membered nitrogen-containing ring,and R1 and R2 are each independently an alkyl group having 1 to 8 carbon atoms.