Sodium Battery Cell Electrolyte for SO2 Solubility and Oxidation Stability
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Solution Overview
Problem
Sodium-ion batteries face challenges with electrolyte decomposition, limited solubility of conductive salts in SO2-based electrolytes, and safety risks due to flammability, leading to reduced stability and operational reliability.
Innovation Solution
A rechargeable battery cell design using an SO2-based electrolyte with a specific conductive salt formula (I) that forms a stable liquid solvate complex with SO2, ensuring high solubility and oxidation stability, and incorporating a negative electrode with metallic sodium or sodium-storing materials to enhance performance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an SO2-based electrolyte is used to improve ionic conductivity, then solubility of conductive salts is enhanced, but oxidation stability deteriorates leading to electrolyte decomposition above certain cell voltage
Solution Approach 1:
The patent modifies the chemical structure of the conductive salt by introducing fluorinated alkyl groups (R1-R4) with specific constraints (at least one being CF3 or OSO2CF3). This parameter change in molecular structure enhances both solubility in SO2 and oxidation stability, allowing the electrolyte to maintain reliability up to 4.2V or higher without decomposition.
Solution Approach 2:
The conductive salt combines aluminum or boron central atom with fluorinated organic ligands (formula I), creating a composite structure that integrates inorganic core with organic functional groups. This composite approach achieves synergistic effects: the inorganic center provides ionic conductivity while the fluorinated organic groups provide oxidation resistance and solubility in SO2.
2Reliability
If conventional conductive salts are used in SO2-based electrolytes, then ionic conductivity is achieved, but solubility is limited reducing cell performance
Solution Approach 1:
The patent introduces fluorinated alkyl groups (R1-R4) with specific constraints (at least one being CF3 or OSO2CF3) into the conductive salt structure. This parameter change significantly enhances solubility in SO2 while maintaining ionic conductivity, resolving the contradiction between these two properties.
3Reliability
If organic electrolytes are used in sodium-ion batteries, then ion conduction is enabled, but flammability increases creating safety risks
Solution Approach 1:
The patent uses SO2 (sulfur dioxide) as the electrolyte solvent instead of flammable organic solvents. SO2 is an inert, non-flammable gas that forms a safe electrolyte environment while enabling sodium ion conduction through the formulated conductive salts, thereby eliminating fire hazards.
4Quantity of substance
If lithium is used as active metal to achieve high energy density, then electrical energy storage is maximized, but availability and cost increase
Solution Approach 1:
The patent replaces expensive and scarce lithium with abundant and inexpensive sodium as the active metal. By formulating specialized conductive salts with formula (I) that enable efficient sodium ion conduction, the patent achieves cost-effective battery manufacturing while maintaining competitive energy density through optimized sodium-based electrochemistry.
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 provides a rechargeable battery cell with improved ionic conductivity, reduced self-discharge, and increased service life, along with enhanced safety and operational reliability, while using inexpensive and accessible sodium as the active metal.
Implementation Method 1
The electrolyte is based on SO2 and contains at least one first conductive salt with the formula (I)... which forms a stable liquid solvate complex with SO2, ensuring high solubility and oxidation stability
Implementation Method 2
The active metal of a rechargeable battery cell is the metal whose ions migrate within the electrolyte to the negative or positive electrode during charging or discharging of the cell and take part in electrochemical processes there
Implementation Method 3
Above a certain upper cell voltage of the rechargeable battery cell, the electrolyte is electrochemically decomposed by oxidation. This process often leads to the irreversible destruction of components of the electrolyte and thus to failure of the rechargeable battery cell
Data Source
AI summary
A rechargeable battery cell has an active metal, at least one positive electrode, at least one negative electrode, a housing and an electrolyte. The active metal is sodium and the electrolyte is based on SO2 and contains a first conductive salt which has the formula (I)R1, R2 and R3 can be a halogen atom, a hydroxy group or a chemical group —OR5. R4 can be a hydroxy group or a chemical group —OR5. R5 can be C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C6-C14 aryl or Cs-C14 heteroaryl. The aliphatic, cyclic, aromatic and heteroaromatic groups can be unsubstituted or substituted. Z is aluminum or boron. At least two of the substituents R1, R2, R3 and R4 can jointly form a chelate ligand which is coordinated to Z.