Solid State Polymer Electrolyte for 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 the need for separators that can introduce contamination and decomposition, limiting their operational range and durability.
Innovation Solution
A solid-state polymer electrolyte comprising an ionic liquid and polymer, along with specific additives, is used in ultracapacitors to maintain performance between -40°C and 250°C, eliminating the need for separators by using a polymer electrolyte that provides mechanical separation and enhanced ion mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metallic canister is used to provide robust physical protection for the energy storage cell, then mechanical strength is improved, but electrochemical reactions increase at elevated temperatures leading to premature degradation
Solution Approach 1:
A corrosion-resistant coating layer is applied to the metallic canister to act as an intermediary barrier between the metal and the electrolyte. This coating prevents direct electrochemical reactions while maintaining the mechanical protection benefits of the metallic structure, thereby improving reliability at elevated temperatures.
Solution Approach 2:
The canister is designed as a composite structure combining metallic material with a corrosion-resistant coating layer. This composite approach leverages the mechanical strength of metal while the coating provides electrochemical stability, resolving the contradiction between strength and reliability.
2Ease of manufacture
If conventional electrolytes are used in EDLCs, then manufacturing ease is improved, but performance degrades at temperatures over 200°C
Solution Approach 1:
The electrolyte composition is modified by changing key parameters such as using ionic liquids instead of conventional organic electrolytes. This parameter change enables the electrolyte to maintain stability and performance at temperatures over 200°C while remaining manufacturable through established processes.
Solution Approach 2:
The electrolyte is formulated as a composite system combining ionic liquids with specific additives and chelating agents. This composite approach maintains ease of manufacture while extending the operating temperature range beyond 200°C, resolving the contradiction between manufacturing ease and temperature performance.
3Reliability
If a separator is used to prevent contact between electrodes, then short circuit prevention is improved, but contamination and decomposition occur at elevated temperatures
Solution Approach 1:
The separator component is completely removed from the EDLC design. Instead of using a separate separator layer, the patent employs a separator-less architecture where the electrolyte itself and electrode positioning prevent short circuits, thereby eliminating the source of contamination and decomposition associated with separators at elevated temperatures.
Solution Approach 2:
The electrolyte and electrode structure are designed to self-prevent short circuits without requiring a separate separator component. The electrolyte formulation and electrode arrangement work together to maintain electrical isolation, allowing the system to prevent short circuits while avoiding separator-related contamination and decomposition.
4Temperature
If the EDLC is designed for high temperature operation, then temperature range is improved, but leakage current increases
Solution Approach 1:
The electrolyte composition parameters are optimized by using ionic liquids with specific molecular structures and additives that suppress leakage current. This parameter optimization enables high temperature operation while minimizing energy loss through leakage, resolving the contradiction between temperature range and energy 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 solution enables robust operation of ultracapacitors over a wide temperature range with improved durability and voltage stability, reducing leakage current and maintaining high energy and power density.
Implementation Method 1
a solid state polymer electrolyte is disclosed for use in an ultracapacitor. The electrolyte includes an ionic liquid and a polymer
Implementation Method 2
eliminating the need for separators by using a polymer electrolyte that provides mechanical separation and enhanced ion mobility
Data Source
AI summary
A solid state polymer electrolyte is disclosed for use in an ultracapacitor. The electrolyte includes an ionic liquid and a polymer and may include other additives, wherein an ultracapacitor that utilizes the solid state electrolyte is configured to output electrical energy at temperatures between about −40° C. and about 250° C. or more.