Ester-Modified Nonaqueous Electrolyte for Battery Temperature Stability
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Solution Overview
Problem
Lithium secondary batteries face deterioration in electrochemical properties across a broad temperature range due to decomposition of nonaqueous electrolytic solutions, leading to worsened cycle properties and lithium ion migration issues.
Innovation Solution
A nonaqueous electrolytic solution with an electrolyte salt dissolved in a solvent containing 0.01 to 40% by volume of a specific ester having two alkyl groups at the α-position carbon of the carbonyl group, which enhances electrochemical stability and forms a low-resistance coating film, improving charge-discharge cycles from low to high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional nonaqueous electrolytic solutions are used in lithium secondary batteries, then the batteries can operate with basic electrochemical properties, but the electrochemical properties deteriorate in a broad temperature range due to decomposition of the electrolytic solution
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolytic solution by introducing a specific ester compound with two alkyl groups at the α-position carbon of the carbonyl group (formula I) at controlled concentrations (0.01-40% by volume). This parameter change stabilizes the methine structure of the ester, preventing decomposition across a broad temperature range from low to high temperatures, thereby improving reliability without sacrificing compositional stability
Solution Approach 2:
The patent creates a composite electrolytic solution system by combining the specific ester compound (formula I) with conventional electrolyte solvents and lithium salts. This composite material approach allows the ester to form a low-resistance coating film that protects the electrodes while maintaining the overall stability and electrochemical functionality of the electrolytic solution across varying temperatures
2Quantity of substance
If the nonaqueous electrolytic solution is reduced in volume to increase electrode density, then the battery capacity increases, but the electrochemical characteristics worsen due to decomposition of the reduced electrolytic solution volume
Solution Approach 1:
The patent modifies the electrolytic solution composition by incorporating the specific ester compound (formula I) at optimized concentrations. This parameter change enables the formation of a protective coating film that reduces resistance and prevents decomposition, allowing the electrolytic solution volume to be reduced while maintaining or improving electrochemical characteristics and battery capacity
3Quantity of substance
If micronized powdering of negative electrode material is promoted to increase surface area, then initial battery capacity increases, but the nonaqueous solvent is acceleratingly reduced and decomposed leading to worsened battery performances
Solution Approach 1:
The patent applies preliminary action by having the specific ester compound (formula I) in the electrolytic solution form a protective coating film on the micronized negative electrode material before significant decomposition can occur. This pre-formed coating prevents accelerated solvent decomposition that would otherwise result from the high surface area of micronized particles, thereby preserving battery performance over multiple cycles
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 significantly improves electrochemical properties in a broad temperature range by stabilizing the methine structure of the ester, reducing resistance, and maintaining battery performance without excessive viscosity, thus enhancing lithium ion mobility and battery capacity retention.
Implementation Method 1
an initial battery capacity thereof is high but a nonaqueous solvent is acceleratingly reduced and decomposed as compared with a negative electrode of a carbon material since a micronized powdering of the material is promoted during cycles
Implementation Method 2
a nonaqueous electrolytic solution including a lithium salt and a nonaqueous solvent
Data Source
AI summary
The present invention is to provide a nonaqueous electrolytic solution prepared by dissolving an electrolyte salt in a nonaqueous solvent, wherein the nonaqueous solvent includes 0.01 to 40% by volume of an ester having two alkyl groups at the α-position carbon of the carbonyl group and being represented by the following general formula (I), and an energy storage device.(in the above formula, R1 is an alkyl group, an alkenyl group or an alkynyl group in which at least one of the hydrogen atoms may be substituted with a halogen atom, R2 and R3 are an alkyl group in which at least one of the hydrogen atoms may be substituted with a halogen atom, and R2 and R3 may be linked to each other to form a ring. However, when R2 and R3 do not form a ring, R3 is an alkyl group in which at least one of the hydrogen atoms may be substituted with a halogen atom.).