Sulfur Dioxide Electrolyte Lithium Cell Design
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Solution Overview
Problem
Conventional lithium-ion batteries face safety risks due to organic electrolytes, particularly in high-capacity applications, leading to increased costs, volume, and reduced energy density, and they are irreversibly damaged when discharged below 2.7 V, limiting their deep discharge capability.
Innovation Solution
A rechargeable lithium battery cell with a sulfur dioxide (SO2)-containing electrolyte and a porous positive electrode structure that allows lithium deposition, ensuring high ionic conductivity and preventing electronic short circuits, while using lithium tetrachloroaluminate as a conductive salt and incorporating a lithium dithionite layer to enhance safety and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic electrolyte is used in lithium-ion cells, then ion mobility is achieved, but safety risks increase due to flammability
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by replacing organic solvents with inorganic sulfur dioxide and using aluminum chloride-based conductive salts, fundamentally altering the electrolyte's physical and chemical properties to eliminate flammability while maintaining ionic conductivity
Solution Approach 2:
The patent creates an inert chemical environment by using sulfur dioxide as the electrolyte solvent and aluminum chloride-based salts, which do not support combustion and are chemically stable, thereby eliminating the flammability hazard associated with organic electrolytes
2Reliability
If safety measures are added to reduce flammability risks, then safety is improved, but device complexity and costs increase
Solution Approach 1:
The patent converts the inherently safe chemical properties of inorganic sulfur dioxide and aluminum chloride into a beneficial electrolyte system that is non-flammable by design, eliminating the need for additional safety measures such as flame inhibitors, protective coatings, or complex monitoring systems required with organic electrolytes
3Ease of operation
If organic lithium-ion cells are discharged below 2.7 V, then deep discharge capability is achieved, but the cell is irreversibly damaged
Solution Approach 1:
The patent changes the electrochemical window and reaction mechanisms by using inorganic sulfur dioxide electrolyte with aluminum chloride-based salts, enabling the cell to withstand and reversibly operate at potentials below 2.7 V without the irreversible damage that occurs in organic electrolyte systems
4Quantity of substance
If electrode thickness is increased to improve energy density, then energy density is improved, but ion transport efficiency decreases
Solution Approach 1:
The patent changes the ionic conductivity parameter of the electrolyte by using inorganic sulfur dioxide with aluminum chloride-based conductive salts, which provide high ionic conductivity that enables efficient ion transport even through thicker electrodes, thereby allowing increased energy density without sacrificing 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
The SO2-containing electrolyte and porous structure enable thicker electrodes, higher power density, improved safety, and deep discharge capability, achieving higher energy density and cycle life while maintaining cost-effectiveness.
Implementation Method 1
the mobility of the ions that cause the charge transport is at least partially due to the SO2
Implementation Method 2
the active cations, which react as a metal when charging the battery cell on the negative electrode by being incorporated into a host lattice or by alloying or by deposition
Implementation Method 3
a porous positive electrode structure that allows lithium deposition
Data Source
Figure 1~2
AI summary
The invention relates to a rechargeable, non-aqueous electrochemical battery cell which has a negative electrode, a positive electrode and a sulphur-dioxide containing electrolyte.