Non-Aqueous Electrolyte Additive for Stable SEI in Li-Ion Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face degradation issues due to transition metal ion dissolution from the positive electrode, leading to instability of the solid electrolyte interphase (SEI) at high temperatures, which accelerates negative electrode degradation and causes swelling, necessitating a solution to enhance high-temperature cycle and storage characteristics.
Innovation Solution
A non-aqueous electrolyte with a specific additive, represented by Formula 1, which forms a stable SEI film on the negative electrode and suppresses the dissolution of transition metal ions, improving electrode-electrolyte interface stability and durability by incorporating a pyrrole structure with an amine substituent for high binding energy with PF5 by-products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-rich positive electrode active material is used to increase capacity, then energy density is improved, but stability deteriorates due to transition metal ion dissolution
Solution Approach 1:
The patent introduces a specific additive compound (Formula 1) as an intermediary substance between the nickel-rich positive electrode and the electrolyte. This additive forms a protective interface layer that mediates the interaction, preventing direct contact and harmful reactions between the positive electrode and electrolyte, thereby suppressing transition metal ion dissolution while maintaining high capacity
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating a specific additive with defined molecular structure (Formula 1 containing nitrogen and oxygen atoms). This parameter change in electrolyte composition alters the interfacial properties, creating a more stable environment that prevents metal ion dissolution from the nickel-rich positive electrode
2Quantity of substance
If high voltage operation is adopted to increase capacity, then energy density is improved, but side reactions increase causing electrolyte degradation
Solution Approach 1:
The additive compound (Formula 1) acts as an intermediary layer at the positive electrode interface, preventing direct harmful interactions between the high-voltage electrode and electrolyte. This mediator suppresses side reactions and electrolyte degradation even under high voltage operating conditions
Solution Approach 2:
The additive performs preliminary protective action by forming a stable interface layer on the positive electrode before harmful side reactions can occur. This pre-formed protective layer prevents electrolyte degradation and suppresses harmful reactions during high-voltage operation
3Quantity of substance
If transition metal ions are dissolved from positive electrode, then capacity is improved through ion transport, but SEI passivation ability deteriorates
Solution Approach 1:
The additive (Formula 1) serves as an intermediary that filters and regulates ion transport at the positive electrode interface. It allows necessary ion transport for capacity while simultaneously blocking the pathway for metal ions that would degrade SEI passivation ability, thus resolving the contradiction between ion transport and SEI stability
4Speed
If battery is operated at high temperature, then reaction kinetics are improved, but degradation is accelerated
Solution Approach 1:
The additive compound forms a thermally stable intermediary layer at the electrode interface that maintains its protective function at high temperatures. This mediator enables fast reaction kinetics while preventing thermal degradation, as the protective layer remains intact and functional under elevated temperature conditions
Solution Approach 2:
The patent changes the thermal stability parameters of the electrode-electrolyte interface by incorporating the heat-resistant additive (Formula 1). This parameter modification allows the system to maintain both fast kinetics and high stability at elevated temperatures, overcoming the typical trade-off between reaction speed and thermal stability
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 the lithium secondary battery's performance by forming a stable SEI film, reducing resistance, and suppressing additional decomposition reactions, thereby improving high-temperature cycle and storage characteristics, leading to increased battery durability and overall performance.
Implementation Method 1
forming a stable solid electrolyte interphase (SEI) film on the negative electrode
Implementation Method 2
suppressing the dissolution of transition metal ions from a positive electrode
Implementation Method 3
incorporating a pyrrole structure with an amine substituent for high binding energy with PF5 by-products
Data Source
AI summary
A non-aqueous electrolyte including an additive represented by Formula 1 is described:wherein in Formula 1, R may be any one selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, and a cycloalkenyl group having 3 to 12 carbon atoms, R1 and R2 may each independently be any one selected from the group consisting of hydrogen (H), an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, and a cycloalkenyl group having 3 to 12 carbon atoms, and A may be an alkylene group having 1 to 5 carbon atoms.