Non-Aqueous Battery Electrolyte Hybrid Coating for 45°C Cycle Life
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries, particularly lithium ion batteries, face reduced cycle characteristics at high temperatures due to the decomposition of carboxylic acid ester-based electrolyte solutions, leading to increased reaction resistance and capacity retention issues.
Innovation Solution
Incorporating a carboxylic anhydride and a sulfonyl imide compound in the electrolyte solution, which forms a hybrid coating on the negative electrode, enhancing lithium ion diffusivity, reducing reaction resistance, and improving cycle characteristics even at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a carboxylic acid ester is used for the electrolyte solution to reduce viscosity and improve room temperature cycle characteristics, then the cycle characteristics at room temperature are improved, but the cycle characteristics are reduced at high temperature of about 45°C
Solution Approach 1:
A cyclic carboxylic acid ester compound is introduced as an intermediary substance between the carboxylic acid ester and the electrode. This intermediary forms a protective coating on the electrode surface that prevents direct harmful interactions at high temperatures while allowing beneficial low-temperature operation to continue
Solution Approach 2:
The chemical composition parameters of the electrolyte solution are changed by adding a cyclic carboxylic acid ester compound with specific structural characteristics. This parameter change modifies the electrolyte's behavior at different temperatures, enabling it to maintain stability at 45°C while preserving the low-viscosity benefits at room temperature
2Reliability
If a carboxylic acid ester-based electrolyte solution is used to improve ion conductivity, then the ion conductivity is improved, but the electrolyte solution decomposes at high temperature leading to increased reaction resistance
Solution Approach 1:
The cyclic carboxylic acid ester compound undergoes controlled decomposition or reaction at high temperatures to form a protective film on the electrode surface. This converts the potentially harmful decomposition into a beneficial protective mechanism that prevents further electrolyte degradation and maintains ion conductivity
Solution Approach 2:
The cyclic carboxylic acid ester compound acts in advance to form a protective coating on the electrode surface before the main electrolyte decomposition occurs. This preliminary protective layer prevents the harmful decomposition reactions that would otherwise increase reaction resistance
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 hybrid coating formed by the carboxylic anhydride and sulfonyl imide compound significantly improves cycle characteristics at 45°C by inhibiting electrolyte solution decomposition, maintaining capacity retention, and allowing the electrolyte to follow electrode expansion and contraction, thus maintaining battery performance.
Implementation Method 1
the negative electrode includes a coating derived from a sulfonyl imide compound and a carboxylic anhydride
Implementation Method 2
charging the uncharged battery, thereby forming, on the negative electrode, a coating derived from a sulfonyl imide compound and a carboxylic anhydride
Data Source
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AI summary
Disclosed is a non-aqueous electrolyte secondary battery including: a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte solution, wherein the electrolyte solution includes a solvent, a solute, and a carboxylic anhydride, the solvent includes a carboxylic acid ester compound, and the solute includes a sulfonyl imide compound.