Sodium Battery Electrolyte Additives for High-Temperature Cycling
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Solution Overview
Problem
Sodium secondary batteries suffer from poor high-temperature cycling performance and severe high-temperature gas generation, limiting their application in large-scale energy storage systems.
Innovation Solution
Incorporating a sulfate ester compound or a sulfonate ester compound as an additive in the electrolyte, which forms a stable and uniform solid electrolyte interface (SEI) on the negative electrode, reducing direct contact between the electrode and solvent, thereby enhancing structural stability and minimizing side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in sodium secondary batteries, then the batteries can operate, but they exhibit poor high-temperature cycling performance and severe high-temperature gas generation
Solution Approach 1:
The patent introduces a mediator substance (sulfone compound or cyclic sulfate ester compound) into the electrolyte system. This mediator acts as an intermediary that preferentially reacts with the electrode surface to form a protective SEI layer, preventing direct contact between the electrode and the main electrolyte solvent, thereby suppressing gas-generating side reactions while maintaining electrochemical performance
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by incorporating specific sulfone compounds (e.g., sulfolane, sultone) or cyclic sulfate esters at controlled concentrations (0.1-10 wt%). This parameter modification alters the decomposition behavior and reaction pathways at the electrode interface, leading to formation of stable SEI layers that suppress high-temperature gas generation
2Reliability
If the negative electrode directly contacts the solvent, then ion transport is efficient, but side reactions occur leading to poor high-temperature performance
Solution Approach 1:
The patent employs preliminary action by having the sulfone compound or cyclic sulfate ester react first during initial cycles to form a stable SEI protective layer on the negative electrode surface. This pre-formed layer prevents subsequent direct contact between the electrode and electrolyte solvent, eliminating side reactions during normal operation while maintaining ion transport efficiency
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
Improves high-temperature cycling performance, reduces gas generation, and enhances electrochemical and safety performance of sodium secondary batteries.
Implementation Method 1
The sulfate ester compound or the sulfonate ester compound has a low lowest unoccupied molecular orbital (LUMO) absolute value, which allows it to be reduced on a surface of the negative electrode, forming an SEI mainly composed of an organic sulfide
Data Source
AI summary
This application provides an electrolyte for a sodium secondary battery, a sodium secondary battery, and an electric device. An electrolyte for a sodium secondary battery is provided, where the electrolyte includes an additive, and the additive includes a sulfate ester compound or a sulfonate ester compound. In this application, through the addition of an additive, including a sulfate ester compound or a sulfonate ester compound, in the electrolyte, the high-temperature cycling performance of the battery can be improved, the high-temperature gas generation phenomenon of the battery can be alleviated, and the electrochemical performance and safety performance of the battery can be improved.