Non-Aqueous Electrolyte Additives for High-Temperature Li Battery Cycling
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Solution Overview
Problem
Existing lithium secondary batteries experience increased resistance and reduced cycle-life characteristics during high-temperature storage, which affect their performance and safety.
Innovation Solution
A non-aqueous electrolyte comprising a non-aqueous organic solvent, lithium salt, and an additive represented by Chemical Formula 1, which includes at least one of fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, or cyanoethylene carbonate, is used to form a thin cathode electrolyte interphase film, reducing internal resistance and inhibiting gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in lithium secondary batteries, then the batteries can operate at high temperatures, but the battery resistance increases significantly and cycle-life characteristics deteriorate
Solution Approach 1:
The patent introduces a specific additive compound (Formula 1) as an intermediary substance between the electrolyte and the electrode. This additive acts as a mediator that forms a protective interface film, preventing direct harmful interactions between the electrolyte and electrode at high temperatures, thereby suppressing resistance increase while maintaining cycle-life characteristics
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating a specific additive with defined structural parameters (I, m, n integers from 0 to 10, with at least one from 1 to 10, and at least two of Ra, Rb, Rc being SCN). This parameter change in the electrolyte composition enables the system to maintain stable electrical resistance and improved cycle-life at elevated temperatures
2Temperature
If high temperature storage is performed, then battery performance can be tested for thermal stability, but resistance increases and gas generation occurs reducing safety
Solution Approach 1:
The additive in the electrolyte performs preliminary protective action by forming a stable cathode electrolyte interphase film before thermal degradation can occur. This pre-formed protective layer prevents subsequent harmful effects such as gas generation and metal elution during high temperature storage, thereby ensuring safety while allowing thermal stability testing
Solution Approach 2:
The patent converts the potentially harmful high temperature condition into a beneficial testing opportunity by using the additive to create a thermally stable electrolyte system. The additive transforms the high temperature environment from a degradation-inducing condition into a safe testing condition that validates thermal stability without causing gas generation or metal elution
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 effectively suppresses resistance increases and improves cycle-life characteristics at room temperature by forming a protective film on the positive electrode, enhancing battery performance and safety.
Implementation Method 1
enhance cycle-life characteristics by forming a stable cathode electrolyte interphase film
Implementation Method 2
inhibiting gas generation and metal elution, even at high temperatures
Data Source
AI summary
Provided are a non-aqueous electrolyte for a lithium secondary battery and a lithium secondary battery including the same, and the non-aqueous electrolyte for the lithium secondary battery including a non-aqueous organic solvent, a lithium salt, and an additive represented by Chemical Formula 1.