EDLC Electrolyte Stabilizer for High Voltage Stability
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Solution Overview
Problem
Existing electric double-layer capacitors (EDLCs) face instability at normal operating conditions, particularly at high voltages and temperatures, leading to capacitance loss, increased equivalent series resistance (ESR), and gas generation, which reduces their lifespan and performance.
Innovation Solution
An electrolyte formulation comprising an ionic species, a solvent, and a stabilizer, such as benzonitrile, is used to enhance the stability of EDLCs, reducing degradation, ESR rise, and gas generation, allowing operation at higher voltages and temperatures while maintaining capacitance and extending the device's life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known electrolytes are used in EDLCs, then the device can operate at normal conditions, but the electrolyte becomes unstable at high voltage or high temperature conditions leading to capacitance loss and gas generation
Solution Approach 1:
A stabilizer compound acts as an intermediary substance added to the electrolyte formulation. This stabilizer preferentially reacts with or adsorbs onto the electrode surfaces, forming a protective interface that prevents direct contact and harmful reactions between the unstable electrolyte components and the electrodes at high voltages and temperatures, thereby maintaining electrolyte stability without limiting the operating temperature range
Solution Approach 2:
The electrolyte formulation's composition parameters are modified by adding a specific stabilizer compound at controlled concentrations. This changes the chemical parameters of the electrolyte system, creating a new formulation that maintains stability across a broader temperature and voltage range while preserving the desired electrochemical performance characteristics
2Duration of action of moving object
If known electrolytes are used in EDLCs, then the device can function, but capacitance is lost and ESR increases over time during operation
Solution Approach 1:
The stabilizer compound performs preliminary protective action by preferentially reacting with or adsorbing onto electrode surfaces during initial cycles or at the start of operation. This creates a stable protective interface layer before harmful degradation reactions can occur, preventing capacitance loss and ESR increase throughout the device's operational life
Solution Approach 2:
The stabilizer serves as a protective intermediary between the electrolyte and electrode surfaces. It forms a stable interface layer that mediates the interaction between electrolyte components and electrodes, preventing direct harmful reactions that would lead to capacitance degradation and ESR increase over time
3Ease of operation
If known electrolytes are used in EDLCs, then the device can operate, but gas is generated leading to mechanical deformation and reduced performance
Solution Approach 1:
The stabilizer compound acts as an intermediary that prevents gas-generating side reactions between the electrolyte and electrodes. By forming a protective interface and suppressing parasitic reactions, it eliminates gas generation during normal operation, ensuring operational continuity without mechanical deformation from gas pressure
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 formulation significantly improves the stability and lifespan of EDLCs by retaining capacitance, reducing ESR increase, and minimizing gas generation, enabling operation at higher voltages and temperatures with longer cycle life and reduced mechanical deformation.
Implementation Method 1
the stabilizer can slow down degradation of the electrolyte... such that the stabilizer can prevent the electrolyte from breaking down
Implementation Method 2
Without being bound by theory, the aromatic group... can have an affinity for the cathode and/or anode surface... The nitrile group... can give the stabilizer a high dielectric constant
Implementation Method 3
The EDLC is infiltrated with an electrolyte such as, for example, an aqueous electrolyte... or a non-aqueous electrolyte. Known electrolytes typically include an aqueous or non-aqueous solvent which contains one or more dissolved ionic species
Implementation Method 4
Electric double layer capacitors (EDLCs) which are also referred to as ultracapacitors or supercapacitors... An electrolyte formulation suitable for use in an energy storage device
Data Source
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AI summary
Embodiments described herein relate generally to electric double layer capacitors having an electrolyte formulation that includes a quantity of a stabilizing additive such that the electrochemical double layer capacitors retain cell capacitance for longer periods of time, generate less gas during operation, and experience less long term ESR. In some embodiments, an electrolyte formulation includes an ionic species, a solvent, and a stabilizer. In some embodiments the stabilizer contains a moiety that promotes adsorption to a surface, such as a carbon surface, and a moiety that promotes polarity of the stabilizer. In some embodiments, the solvent can be a nitrile compound and the stabilizer can be a compound of the formula I: Such that R is H, saturated or unsaturated, linear or branched, acyclic carbon group, OH, halogen NH2, NO2, (SO)2CF3, or monocyclic or polycyclic aryl, and n is an integer from 0 to 5.