Sodium Battery Electrolyte Composition for Cycle Stability
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Solution Overview
Problem
Sodium secondary batteries face challenges with low stability and corrosion due to hydrofluoric acid production from halide anions in conventional electrolytes, limiting their cycle life and efficiency.
Innovation Solution
An electrolyte composition comprising an alcohol compound as a hydrogen bond donor and a sodium salt, specifically a deep eutectic solvent with a balanced molar ratio, is developed to enhance cycle stability and ion conductivity, preventing halogen-containing acid formation and improving ion transportation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes containing halide anions are used in sodium secondary batteries, then ion conductivity is achieved, but hydrofluoric acid is produced causing corrosion and low stability
Solution Approach 1:
The patent removes harmful halide anions (such as PF6-, CF3SO3-) from the electrolyte composition and replaces them with non-halide alternatives (such as BF4-, ClO4-, AlCl4-). This extraction of the harmful component eliminates the source of hydrofluoric acid production while maintaining the electrolyte's ion conductivity and electrochemical functionality.
Solution Approach 2:
The patent converts the harmful effect of halide anion decomposition into a benefit by deliberately selecting sodium salts that do not produce hydrofluoric acid. The replacement electrolyte composition maintains or improves ion conductivity while eliminating corrosion, effectively turning the problem of electrolyte degradation into a solution that enhances battery stability and cycle life.
2Quantity of substance
If aqueous electrolyte is used in sodium secondary battery, then cost is reduced and safety is improved, but energy density becomes low
Solution Approach 1:
The patent changes the fundamental parameter of the electrolyte from aqueous to non-aqueous (deep eutectic solvent), which fundamentally alters the energy density characteristics. This parameter change enables the battery to achieve higher energy density while maintaining the cost-effectiveness and safety advantages of alternative electrolyte systems.
Solution Approach 2:
The patent employs a composite electrolyte system using deep eutectic solvents formed by combining hydrogen bond donors (such as alcohols, carboxylic acids) with hydrogen bond acceptors (such as salts). This composite approach creates a new class of electrolyte that combines the benefits of low cost and safety with high energy density and wide operating potential.
3Reliability
If deep eutectic solvent is used as electrolyte, then cost is reduced and biocompatibility is improved, but ion conductivity and cycle stability need optimization
Solution Approach 1:
The patent optimizes the molar ratios of hydrogen bond donors to acceptors in the deep eutectic solvent system to achieve optimal ion conductivity. By adjusting these compositional parameters and selecting specific sodium salts with appropriate characteristics, the electrolyte achieves high ion conductivity while maintaining the inherent advantages of deep eutectic solvents including low cost, biocompatibility, and wide operating potential.
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 composition achieves high ion conductivity, extended cycle life, and increased discharge capacity, with improved capacity retention and reduced toxicity, enhancing the overall performance of sodium secondary batteries.
Implementation Method 1
an alcohol compound serving as a hydrogen bond donor and a metallic salt
Implementation Method 2
the deep eutectic solvent has advantages of easier preparation, availability of raw materials, and high biocompatibility
Data Source
AI summary
An electrolyte composition and a sodium secondary battery are provided. The electrolyte composition includes an alcohol compound and a metallic salt, wherein the metallic salt consists of a sodium salt formed. The sodium secondary battery includes the electrolyte composition, a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode.