SO2 Battery Electrolyte Impurity Control
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Solution Overview
Problem
SO2-based electrolytes for lithium cells are limited by their high corrosiveness and contamination with hydroxide and chlorosulfonate groups, which affect the electrical properties and lifespan of battery cells.
Innovation Solution
An SO2-based electrolyte with a low molar concentration of hydroxide groups (<50 mmol/l) and chlorosulfonate groups (<350 mmol/l) is produced by a method involving the reaction of a Lewis acid and Lewis base with sulfur dioxide, ensuring minimal organic content and optimized proportions of SO2 and conductive salts, and using a drying and heating process to minimize impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SO2-based electrolyte is used to achieve high ionic conductivity and non-flammability, then safety and electrical properties are improved, but corrosiveness and impurity contamination increase
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration of hydroxide groups (<50 mmol/l) and chlorosulfonate groups (<350 mmol/l) in the electrolyte, and by optimizing the SO2 to conductive salt molar ratio (2:1 to 10:1). These parameter optimizations reduce corrosiveness and impurity effects while maintaining the high ionic conductivity and non-flammable safety advantages of SO2-based electrolytes.
2Ease of manufacture
If conventional electrolyte preparation methods are used to produce SO2-based electrolyte, then production is simplified, but hydroxide and chlorosulfonate impurities increase
Solution Approach 1:
The patent applies preliminary action by performing drying and heating treatments on the starting materials before electrolyte assembly, and by conducting the electrolyte preparation process in a controlled atmosphere. These preliminary precautions prevent hydroxide and chlorosulfonate impurity formation from the outset, achieving low impurity concentrations without complex post-processing purification steps.
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 the charging capacity and cycle life of battery cells by reducing corrosion and impurity-related issues, enhancing safety and operational reliability.
Implementation Method 1
An SO2-based electrolyte is typically prepared by mixing together the Lewis acid component and Lewis base component of the conductive salt and reacting with gaseous SO2 flowing over or through the mixture. During the exothermic reaction, a Lewis acid/Lewis base adduct is formed
Implementation Method 2
At least one ion of the conductive salt (anion or cation) is mobile in the electrolyte in such a way that ion conduction allows a charge transport between the electrodes
Implementation Method 3
When the conductive salt is dissolved in SO2, its ions become mobile
Implementation Method 4
A method suitable for producing the electrolyte according to the invention is characterized by the following steps: A Lewis acid, a Lewis base, and aluminum are mixed in a solid form. The mixture is maintained at a temperature above a minimum temperature, the minimum temperature being above the melting point of the mixture, but at least 200° C., for a minimum period of 6 hours
Implementation Method 5
An advantage of the SO2-based electrolyte is that it - in contrast to the organic electrolytes of the lithium-ion cells commonly used in practice - cannot burn
Data Source
AI summary
The invention relates to an electrolyte for an electrochemical battery cell, containing sulfur dioxide and a conductive salt. Improved characteristics of a cell filled with the electrolyte are achieved by the molar concentration of hydroxide groups in the electrolyte being at most 50 mmol per liter and the molar concentration of chlorosulfonate groups in the electrolyte being at most 350 mmol per liter.