Nonaqueous Electrolyte Composition for High-Temperature Battery Stability
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Solution Overview
Problem
Existing nonaqueous electrolytic solution batteries suffer from insufficient suppression of gas generation, capacity retention rate decrease, and internal resistance increase when operated at high temperatures, particularly above 70°C.
Innovation Solution
A nonaqueous electrolytic solution comprising a specific fluorosilane compound and a specific anion-containing compound, with a defined mass ratio, forms a composite surface film on the electrode to reduce gas generation and maintain capacity retention and reduce internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiPF6 is used as the electrolyte in nonaqueous electrolytic solution batteries, then good electrochemical performance is achieved at normal operating temperatures, but thermal decomposition occurs at 68°C or higher causing gas generation and internal resistance increase
Solution Approach 1:
The patent introduces LiBF4 as an intermediary substance that mediates between the electrode and LiPF6 electrolyte. LiBF4 decomposes first at lower temperatures to form a protective surface film, preventing direct contact between LiPF6 and electrode materials at high temperatures, thus eliminating the thermal decomposition problem while maintaining electrochemical performance
Solution Approach 2:
The patent applies preliminary action by having LiBF4 decompose before LiPF6 at lower temperatures to form a protective surface film on the electrode. This preliminary decomposition creates a barrier that prevents subsequent high-temperature decomposition of LiPF6, solving the thermal stability issue before it occurs
2Power
If operating temperature is increased to 70°C or higher, then battery power output is improved, but gas generation and internal resistance increase significantly due to electrolyte decomposition
Solution Approach 1:
The patent converts the harmful high-temperature decomposition of LiPF6 into a beneficial process by introducing LiBF4 that decomposes first at lower temperatures. The decomposition of LiBF4 forms a protective film that prevents further decomposition, transforming the potential harm into a protective mechanism that allows high-temperature operation without gas generation
3Stability of the object's composition
If LiPF6 decomposition products react with carbonate electrolyte components, then decomposition reactions proceed, but this causes significant deterioration of battery characteristics at high temperatures
Solution Approach 1:
The patent uses LiBF4 as an intermediary that reacts with carbonate components before LiPF6 decomposition products can. This intermediary reaction forms stable compounds that prevent the detrimental reactions between LiPF6 decomposition products and carbonate, maintaining both electrolyte composition stability and battery reliability at high temperatures
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 reduces gas generation and maintains capacity retention while suppressing internal resistance increase in nonaqueous electrolytic solution batteries operating at high temperatures.
Implementation Method 1
a nonaqueous electrolytic solution comprising an electrolyte, a nonaqueous solvent, a compound represented by general formula (I), and at least one compound selected from a compound having a P=O bond and a P-F bond, a compound having an S=O bond and an S-F bond, and an alkyl sulfate anion-containing compound
Data Source
AI summary
The present invention relates to a nonaqueous electrolytic solution comprising an electrolyte, a nonaqueous solvent, a compound represented by general formula (I), and at least one specific anion-containing compound selected from an anion-containing compound having a P=O bond and a P-F bond, an anion-containing compound having an S=O bond and an S-F bond, and an alkyl sulfate anion-containing compound, in which the mass ratio of the compound represented by the general formula (I) to the specific anion-containing compound satisfies a specific range. The present invention also relates to a nonaqueous electrolytic solution battery comprising a negative electrode and a positive electrode capable of occluding and releasing metal ions, and the nonaqueous electrolytic solution.