Ionic Liquid Electrolyte for High-Temperature Ultracapacitors
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Solution Overview
Problem
Energy storage cells, particularly electric double-layer capacitors (EDLCs), face performance degradation at elevated temperatures due to electrolyte instability and separator-related issues, limiting their operational range and durability in high-temperature applications such as petroleum exploration and geothermal wells.
Innovation Solution
Development of an ultracapacitor with a hermetically sealed housing containing an energy storage cell and an electrolyte comprising an ionic liquid and additives like gelling agents, inorganic powders, and clays, which forms a solid state polymer electrolyte, eliminating the need for a separator and enhancing performance across a wide temperature range from -40°C to 250°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional electrolytes are used in EDLCs, then the device can operate at standard temperatures, but the electrolyte degrades at elevated temperatures above 200°C
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by using ionic liquids instead of conventional electrolytes. This parameter change enables the electrolyte to maintain stability at elevated temperatures up to 200°C and above, resolving the degradation issue while expanding the operating temperature range.
Solution Approach 2:
The patent employs composite materials by combining ionic liquids with specific additives including gelling agents (such as silica or polyacrylonitrile), inorganic powders (such as alumina or titania), and clays (such as bentonite). This composite approach creates a stable electrolyte system that maintains reliability at high temperatures while enabling operation from -40°C to 250°C.
2Reliability
If a separator is used to prevent electrode contact, then short circuits are avoided, but contamination and decomposition occur at high temperatures
Solution Approach 1:
The patent removes the separator component from the EDLC structure entirely. By using ionic liquids with added stabilizers, the electrolyte itself provides sufficient stability to prevent electrode contact and short circuits without requiring a separate separator that would decompose at high temperatures. This extraction eliminates the source of contamination and decomposition.
Solution Approach 2:
The ionic liquid electrolyte with additives serves multiple functions simultaneously: it provides ionic conductivity for charge transfer, acts as a physical barrier preventing electrode contact, and stabilizes the system at high temperatures. This multi-functionality replaces the need for a separate separator component.
3Strength
If metallic canisters are used for physical protection, then robust protection is provided, but electrochemical reactions increase at elevated temperatures
Solution Approach 1:
The patent creates an inert environment by using ionic liquids as the electrolyte medium. Ionic liquids provide a chemically inert atmosphere that prevents electrochemical reactions between the metallic canister and other cell components at elevated temperatures, while the canister continues to provide robust physical protection.
Solution Approach 2:
The patent uses composite materials including inorganic powders (alumina, titania) and ceramic materials in the electrolyte formulation. These composite materials form a protective barrier between the metallic canister and the electrochemical environment, preventing reactions while maintaining the structural integrity and physical protection provided by the metallic canister.
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 improved performance with increased operational lifetime, maximum operating voltage, and temperature durability, along with reduced vapor pressure and leakage current, enabling robust operation under extreme conditions.
Implementation Method 1
an electrolyte comprising an ionic liquid and additives like gelling agents, inorganic powders, and clays, which forms a solid state polymer electrolyte
Implementation Method 2
an ultracapacitor with a hermetically sealed housing containing an energy storage cell and an electrolyte
Implementation Method 3
electric double-layer capacitor (EDLCs), face performance degradation at elevated temperatures due to electrolyte instability
Data Source
AI summary
Disclosed herein is a method for using a high temperature rechargeable energy storage device comprising (a) obtaining an HTRESD; and (b) at least one of (1) cycling the HTRESD by alternatively charging and discharging the HTRESD at least twice over a duration of 20 hours and (2) maintaining a voltage across the HTRESD for 20 hours, such that the HTRESD exhibits a peak power density between 0.005 W/liter and 75 kW/liter after 20 hours when operated at an ambient temperature in an operating temperature range comprising between about −40° C. and about 210° C.