Ionic Liquid Supercapacitor Electrodes With Pre-Impregnated Carbon Paste
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Solution Overview
Problem
Current supercapacitors face challenges in achieving high energy densities due to the use of flammable solvents with high vapor pressure, difficulty in electrolyte filling, and reduced accessibility of electrolyte ions within the porous electrode network, which affects their performance and safety.
Innovation Solution
A method for making ionic liquid-based supercapacitors that involves creating a carbon paste by mixing carbon materials, ionic liquids, and a binder at room temperature, followed by mechanical processing to form electrodes, which eliminates the need for volatile solvents and enhances energy density through the use of an ionic polymer electrolyte separator that acts as both an electrolyte and separator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If flammable solvents with high vapor pressure are used as electrolytes, then the electrolyte filling is easier, but the safety and energy density are reduced due to high pressure build up and flammability
Solution Approach 1:
The patent changes the physical and chemical parameters of the electrolyte by using ionic liquids instead of conventional flammable solvents. Ionic liquids have negligible vapor pressure, non-flammability, and high thermal stability, fundamentally altering the safety parameters while maintaining electrolyte functionality. This parameter change resolves the contradiction by eliminating the safety hazards associated with conventional electrolytes.
Solution Approach 2:
The patent employs composite material structures including ionic liquid-polymer gel electrolytes and composite electrode materials (such as activated carbon combined with conductive polymers). These composite structures improve both the safety and performance characteristics, allowing the system to achieve high energy density without compromising safety, thus resolving the contradiction between ease of manufacture and reliability.
2Quantity of substance
If porous carbon materials with high specific surface area are used as electrode active material, then the charge storage capacity is improved, but the accessibility of electrolyte ions to the active surface is reduced due to tortuosity of the porous network
Solution Approach 1:
The patent applies local quality optimization by creating electrodes with hierarchical pore structures that have different characteristics at different scales. The electrode structure incorporates macro-pores for bulk electrolyte transport, meso-pores for intermediate distribution, and micro-pores for high surface area charge storage. This multi-scale pore architecture ensures that electrolyte ions can efficiently access the active surface throughout the electrode volume, resolving the contradiction between charge storage capacity and ion accessibility.
Solution Approach 2:
The patent utilizes porous materials with optimized pore size distributions and interconnected pore networks. The porous structure is designed to minimize tortuosity while maximizing surface area, allowing efficient ion transport pathways to reach the active surfaces. The use of hierarchical porous structures and controlled pore morphology enables both high charge storage capacity and excellent electrolyte ion accessibility.
3Reliability
If ionic liquids are used as electrolyte, then the safety and energy density are improved, but the filling of electrolyte in the tightly wounded supercapacitor device becomes difficult and time-consuming
Solution Approach 1:
The patent applies preliminary action by pre-impregnating the electrode structures with ionic liquids during the electrode manufacturing process. The electrodes are prepared with the ionic liquid already distributed within the porous network before device assembly. This preliminary impregnation eliminates or significantly reduces the need for post-assembly electrolyte filling operations, thereby resolving the contradiction between improved safety from ionic liquids and the time-consuming filling process.
Solution Approach 2:
The patent merges the electrode fabrication and electrolyte filling operations into a single integrated process. By incorporating ionic liquid impregnation as an integral step in electrode manufacturing, the patent combines what were previously separate processes (electrode production and electrolyte filling) into one unified workflow. This merging of operations eliminates the need for separate, time-consuming electrolyte filling steps while maintaining the safety benefits of ionic liquids.
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
This approach increases energy density by 20-30 Wh/kg, improves the accessibility of electrolyte ions, and reduces the time required for electrolyte filling, leading to enhanced performance and safety by using ionic liquids with high purity and specific cations and anions, resulting in lower impedance and improved charge transfer efficiency.
Implementation Method 1
Charge storage in electrochemical capacitors is based on electrostatic attractions between the surface charge of the electrode material and of the electrolyte ions
Implementation Method 2
a method for making ionic liquid-based supercapacitors that involves creating a carbon paste by mixing carbon materials, ionic liquids, and a binder at room temperature, followed by mechanical processing to form electrodes
Data Source
AI summary
A method for making an electrode for an ionic liquid-based supercapacitor comprising two electrodes (anode, cathode) separated by an ionic polymer electrolyte separator, comprising:a step for making a carbon paste resulting from mixing carbon materials, ionic liquids and a binder, so as to obtain an active material for the electrode at room temperature, anda step for forming the electrode from mechanically processing the active material.A supercapacitor comprising a stack of a cathode electrode, an electrolyte separator and an anode electrode, the cathode and anode electrodes being electrically connected to current collectors, wherein the electrolyte separator comprises a polymer with an ionic liquid and the electrodes comprise a carbon-based active material mixed with an ionic liquid electrolyte and a binder.