Dual-Salt Non-Aqueous Electrolyte for High-Temperature Sodium-Ion Cells
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Solution Overview
Problem
Lithium-ion batteries face resource and cost limitations due to finite lithium reserves and uneven distribution, necessitating the development of sodium-ion batteries with improved high-temperature cycling performance, capacity retention, and reduced volume swelling.
Innovation Solution
A non-aqueous electrolyte for sodium-ion batteries comprising specific sodium salts, including sodium hexafluorophosphate, sodium hexafluoroarsenate, and sodium perchlorate, combined with electron-rich anions such as sulfonate, oxalate, and borate, to regulate the solvation structure and chemical environment of sodium ions, reducing solvent decomposition and gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in sodium-ion batteries, then the battery can operate, but the high-temperature cycling performance and capacity retention are poor
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a dual-salt system (first sodium salt with electron-deficient anion and second sodium salt with electron-rich anion) and optimizing their concentration ratios. This parameter modification fundamentally alters the electrolyte's interaction with electrode materials at high temperatures, improving cycling performance and capacity retention without compromising operational reliability
Solution Approach 2:
The patent creates a composite electrolyte system by combining two different sodium salts with distinct anionic characteristics (electron-deficient and electron-rich). This composite approach allows the electrolyte to simultaneously provide stable film formation (from the first salt) and effective decomposition suppression (from the second salt), resolving the contradiction between reliability and duration under high-temperature conditions
2Reliability
If conventional electrolytes are used in sodium-ion batteries, then the battery can function, but the volume swelling rate after high-temperature storage is high
Solution Approach 1:
The patent modifies the electrolyte's chemical parameters by incorporating a second sodium salt with electron-rich anion in specific concentrations (0.01-0.5 mol/L). This parameter change enhances the electrolyte's ability to suppress solvent decomposition and stabilize the electrode-electrolyte interface, thereby reducing volume swelling while maintaining electrochemical stability
Solution Approach 2:
The second sodium salt with electron-rich anion acts as an intermediary substance that mediates between the electrode material and the solvent. It forms protective interface layers that prevent direct harmful interactions, reducing volume swelling through this intermediary protective mechanism while preserving the electrolyte's electrochemical stability
3Productivity
If traditional electrolyte compositions are used, then the battery can operate, but solvent decomposition and gas generation occur continuously
Solution Approach 1:
The patent changes the chemical composition parameters by introducing the second sodium salt with electron-rich anion at optimized concentrations. This parameter modification fundamentally alters the electrochemical environment, suppressing solvent decomposition reactions and reducing gas generation while maintaining productive battery operation
Solution Approach 2:
The patent converts the potentially harmful electron-deficient anion into a beneficial component by pairing it with an electron-rich anion. The electron-rich anion compensates for the electron-withdrawing effects, transforming what would be a harmful decomposition-promoting feature into a beneficial system that suppresses decomposition and reduces gas generation while maintaining operational capacity
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 electrolyte significantly improves high-temperature cycling performance, capacity retention, and reduces battery volume swelling, enhancing the electrochemical stability and safety of sodium-ion batteries.
Implementation Method 1
the solvation structure of sodium ions and the chemical environment of solvent molecules in the electrolyte can be regulated
Data Source
AI summary
A non-aqueous electrolyte includes: a first sodium salt, where the first sodium salt includes at least one of sodium hexafluorophosphate, sodium hexafluoroarsenate, sodium perchlorate, and sodium trifluoroacetate; and a second sodium salt, where the second sodium salt includes one, two, or more of a sodium salt having sulfonate, a sodium salt having oxalate, a sodium salt having phosphate, and a sodium salt having borate.