Carboxylic Ester Electrolyte for High-Current Capacity Retention
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Solution Overview
Problem
Conventional lithium secondary batteries experience a significant decrease in storage properties and discharge capacity, especially under high-current conditions and high temperatures, due to the negative electrode's reaction with non-aqueous electrolytic solutions.
Innovation Solution
An electrolytic solution containing a carboxylic acid ester and hydroxy group-containing or ether group-containing compounds, with specific concentration and structural preferences, is used to enhance capacity retention and reduce viscosity, allowing stable charge and discharge even under high-current conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional non-aqueous electrolytic solutions are used, then high energy density is achieved, but storage properties deteriorate due to negative electrode reaction
Solution Approach 1:
The patent introduces a mediating substance (carboxylic acid ester with specific structure) into the electrolytic solution to reduce the direct harmful reaction between the negative electrode and the non-aqueous electrolyte. This intermediary component modifies the interface properties and reduces degradation during storage, thereby improving storage properties while maintaining high energy density.
2Reliability
If alcohol, aldehyde, or carboxylic acid ester additives are added to improve storage properties, then storage properties are improved, but discharge capacity decreases at high current values
Solution Approach 1:
The patent precisely controls the concentration parameter of the carboxylic acid ester additive within a specific range (0.01-5% by mass, preferably 0.1-3%). By optimizing this parameter, the patent achieves a balance where storage properties are improved without significantly compromising discharge capacity at high current values, resolving the trade-off between reliability and productivity.
3Adaptability or versatility
If lithium secondary batteries are exposed to high temperature for memory backup, then portability and functionality are improved, but storage properties decrease significantly
Solution Approach 1:
The patent employs a carboxylic acid ester with specific structural characteristics (R-COOR' where R and R' are specific hydrocarbon groups) that forms a protective interface layer during initial use or storage. This layer acts as a sacrificial component that prevents further degradation of the electrode, enabling the battery to maintain acceptable storage properties even when exposed to high temperatures for memory backup functions.
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 electrolytic solution maintains high capacity retention at both room and low temperatures, and under high-current conditions, while providing improved thermal safety and mobility of lithium ions, thus addressing the limitations of conventional lithium secondary batteries.
Implementation Method 1
the viscosity of the electrolytic solution can be decreased and the mobility of lithium ions in the electrolytic solution can be increased
Implementation Method 2
utilize lithium oxidation and reduction
Data Source
AI summary
The present invention provides an electrolytic solution that is less likely to cause a decrease in discharge capacity even under high-current conditions and enables high capacity retention, and a non-aqueous electrolytic solution secondary battery including the electrolytic solution. Provided is an electrolytic solution containing a carboxylic acid ester; and a hydroxy group-containing compound and/or an ether group-containing compound, the electrolytic solution containing the hydroxy group-containing compound and/or the ether group-containing compound in an amount of 50 mass ppm or less.