Rechargeable Lithium Battery Electrolyte for Low-Gas High-Temperature Storage
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in achieving high-temperature lifetime and stability, particularly due to side reactions and gas generation during high-temperature storage, which affect battery performance and internal resistance.
Innovation Solution
An electrolyte composition for lithium batteries comprising a non-aqueous organic solvent, lithium salt, and specific additives (Chemical Formulas 1 and 2) that form a stable solid electrolyte interface (SEI) layer, reducing gas generation and enhancing ion conductivity, especially when combined with high-nickel-based positive and graphite-silicon electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in rechargeable lithium batteries, then basic battery operation is achieved, but high-temperature lifetime and stability deteriorate due to side reactions and gas generation
Solution Approach 1:
The patent introduces a fluorinated cyclic carbonate compound as an intermediary substance that mediates between the electrolyte and electrode surfaces. This compound preferentially reacts to form a stable protective film that prevents direct contact between the electrolyte and electrodes, thereby suppressing side reactions and gas generation at high temperatures while maintaining basic battery operation
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating a fluorinated cyclic carbonate compound with specific molecular structure (containing fluorine atoms and cyclic carbonate groups). This parameter change in the electrolyte composition leads to the formation of a more stable solid electrolyte interface (SEI) layer that resists decomposition at high temperatures, thereby improving high-temperature stability and reducing gas generation
2Reliability
If conventional electrolytes are used in rechargeable lithium batteries, then basic ion conduction is achieved, but internal resistance increases at high temperatures due to side reactions
Solution Approach 1:
The fluorinated cyclic carbonate compound acts as a sacrificial intermediary that reacts first to form a stable protective interface layer. This intermediary reaction prevents subsequent unwanted side reactions between the main electrolyte and electrode materials at high temperatures, thereby extending battery lifetime and maintaining lower internal resistance
Solution Approach 2:
The patent converts the potential harmful effect of electrolyte decomposition at high temperatures into a beneficial protective mechanism. The fluorinated cyclic carbonate compound is designed to decompose preferentially to form a stable, protective film that prevents further decomposition and harmful side reactions, thereby transforming the harmful thermal instability into a protective high-temperature resistance mechanism
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 improves high-temperature stability and reduces internal resistance, thereby enhancing the battery's lifetime and capacity by minimizing side reactions and gas formation, particularly with silicon particles.
Implementation Method 1
specific additives (Chemical Formulas 1 and 2) that form a stable solid electrolyte interface (SEI) layer, reducing gas generation and enhancing ion conductivity
Implementation Method 2
enhancing ion conductivity, especially when combined with high-nickel-based positive and graphite-silicon electrodes
Data Source
AI summary
A rechargeable lithium battery including an electrolyte. The electrolyte includes a non-aqueous organic solvent, a lithium salt, and an additive. The additive includes a first compound represented by Chemical Formula 1 and a second compound represented by Chemical Formula 2.