Non-Aqueous Battery Electrolyte for Stable SEI Film Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium ion batteries face issues with transition metal ion elution and decomposition, leading to increased resistance, self-discharge, and safety risks due to the vulnerability of electrolytes like LiPF6 to heat and moisture, which degrade the solid electrolyte interphase (SEI) film.
Innovation Solution
A non-aqueous electrolyte solution for lithium secondary batteries containing a compound with an isothiocyanate (-NCS) terminal group forms a stable film on electrodes, scavenging Lewis acids and suppressing transition metal ion elution, thereby improving high-temperature storage safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrolyte such as LiPF6 is used, then high ionic conductivity is achieved, but thermal decomposition occurs generating Lewis acids that erode the passivation film and induce transition metal ion elution
Solution Approach 1:
The patent introduces a passivation film as an intermediary layer between the electrolyte and the positive electrode. This film acts as a protective barrier that prevents direct contact between the electrolyte (and its decomposition products like Lewis acids) and the positive electrode, thereby preventing transition metal ion elution while still allowing ionic conductivity to function.
Solution Approach 2:
The patent applies preliminary protection by forming a passivation film on the positive electrode surface before the electrolyte can decompose and cause harmful effects. This pre-formed protective layer prevents the subsequent erosion and ion elution that would otherwise occur during battery operation.
2Productivity
If transition metal ions are eluted from positive electrode, then electrolyte decomposition is accelerated and gas generation increases, but battery safety and stability deteriorate
Solution Approach 1:
The patent converts the harmful effect of potential electrolyte decomposition into a beneficial protective mechanism. By introducing the passivation film, any decomposition products (Lewis acids) that form are contained and neutralized at the film interface rather than attacking the positive electrode, thus transforming a potentially harmful process into one that is controlled and beneficial for overall battery stability.
Solution Approach 2:
The passivation film serves as an intermediary that intercepts transition metal ions before they can be eluted into the electrolyte. This prevents the catalytic effect of transition metal ions on electrolyte decomposition and subsequent gas generation, thereby maintaining battery safety while preserving performance.
3Reliability
If passivation film is formed on positive electrode, then transition metal ion elution is suppressed, but film stability and resistance to Lewis acid erosion must be maintained
Solution Approach 1:
The patent creates a composite protective structure on the positive electrode surface, combining the passivation film with underlying electrode materials. This composite structure provides enhanced stability and resistance to Lewis acid erosion while maintaining the film's ability to suppress transition metal ion elution.
Solution Approach 2:
The patent optimizes the chemical composition and physical properties of the passivation film to achieve the right balance between suppressing ion elution and maintaining stability. By adjusting film composition parameters, the patent enhances the film's resistance to Lewis acid erosion while preserving its protective function.
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 stabilizes the SEI film, reducing degradation and enhancing battery safety by preventing transition metal ion elution and decomposition, thus improving high-temperature storage performance.
Implementation Method 1
an additive capable of forming a stable film on the surface of a positive electrode and a negative electrode
Implementation Method 2
forming a stable ion conductive film on the electrode surface... suppressing the elution of transition metals
Implementation Method 3
effectively removing a decomposition product of a lithium salt... scavenging Lewis acids generated as a decomposition product of an electrolyte salt
Implementation Method 4
a non-aqueous electrolyte solution used as a medium through which lithium (Li) ions move
Implementation Method 5
an electrolyte, such as lithium hexafluorophosphate (LiPF6), which is dissolved in an organic solvent having a high dielectric constant
Data Source
AI summary
The present disclosure relates to a non-aqueous electrolyte solution for a lithium secondary battery capable of forming a stable film on the surface of an electrode, and a lithium secondary battery including the same. Specifically, the non-aqueous electrolyte solution for a lithium secondary battery of the present disclosure may include a lithium salt, a non-aqueous organic solvent, and a compound represented by Formula 1.