Lithium Battery Electrolyte Additive for High-Temperature Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face issues with thickness expansion and performance degradation at high temperatures due to gas generation and electrode resistance, as well as destruction of the solid electrolyte interface (SEI) film, leading to irreversible reactions.
Innovation Solution
An electrolyte for lithium secondary batteries comprising a non-aqueous organic solvent, a lithium salt, and an additive represented by Chemical Formula 1, which improves high-temperature storage characteristics by controlling the additive's amount (0.1 wt % to 2 wt %) and structure, thereby enhancing the SEI film formation and cycle-life characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional electrolytes are used in lithium secondary batteries, then the batteries can operate at high discharge voltage and high energy density, but the batteries experience gas generation, electrode resistance increase, and SEI film destruction at high temperatures, leading to thickness expansion and performance degradation
Solution Approach 1:
The patent introduces a specific additive compound (cyclic carbonate with fluorinated alkyl groups) as an intermediary substance that mediates between the electrolyte and electrode at high temperatures. This additive forms a protective interface layer that prevents direct harmful interactions between the electrolyte and electrode materials, thereby maintaining battery reliability under thermal stress while preserving the high voltage and energy density characteristics of conventional electrolytes
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating a specific additive at controlled concentrations (0.1-5 wt%). This parameter change alters the electrochemical properties of the electrolyte system, enabling it to maintain stable SEI film formation and prevent gas generation at elevated temperatures, thus resolving the contradiction between temperature stability and overall battery reliability
2Temperature
If the battery operates at high temperatures, then energy delivery is maintained, but the SEI film on the negative electrode is destroyed and by-products are continuously generated, accelerating irreversible reactions and causing performance degradation
Solution Approach 1:
The additive performs preliminary protective action by forming a stable, thermally resistant interface layer on the electrode surface before thermal degradation can occur. This pre-formed protective barrier prevents the destruction of the SEI film that would otherwise happen at high temperatures, thereby preserving the electrode structure and extending cycle life during subsequent high-temperature operation
Solution Approach 2:
The patent converts the potentially harmful high-temperature environment into a beneficial condition by using the thermal energy to drive the formation of a more stable and robust protective interface layer through the additive. This transformed harmful heat into a useful process that strengthens the electrode-electrolyte interface, reducing by-product formation and extending battery cycle life
3Quantity of substance
If conventional electrolyte compositions are used, then electrolyte conductivity is maintained, but gas generation and electrode resistance increase at high temperatures, causing thickness expansion (swelling)
Solution Approach 1:
The additive acts as an intermediary that prevents direct gas-generating reactions between the electrolyte and electrode materials at high temperatures. By forming a protective interface layer, it mediates the interaction to prevent gas generation and electrode resistance increase, thereby maintaining battery dimensional stability while preserving electrolyte conductivity for normal operation
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 electrolyte significantly improves storage characteristics at high temperatures, particularly reducing swelling and maintaining cycle-life performance by optimizing the SEI film formation and electrolyte conductivity.
Implementation Method 1
the solid electrolyte interface (SEI) film formed on the negative active material surface is destroyed at high temperature
Implementation Method 2
enhancing the SEI film formation and cycle-life characteristics
Implementation Method 3
optimizing the SEI film formation and electrolyte conductivity
Implementation Method 4
an organic solvent in which a lithium salt is dissolved has been used
Data Source
AI summary
Disclosed are an electrolyte for lithium secondary battery, and a lithium secondary battery comprising same, the electrolyte comprising: a non-aqueous organic solvent; lithium salt; and an additive represented by Chemical Formula 1.