Electrolytes for supercapacitors by E-Lyte Innovations

Electrolyte for supercapacitors

Electrolyte salt: TEA BF4

Composition example: TEA BF4  solved in ACN 

Solvent: ACN (Acetonitrile)

Batch sizes: 25 g – 2 kg (bigger amounts available on request )

Packaging Electrolyte: UN-safety aluminum bottles (made in Germany), sealed in pouch bags under an inert gas atmosphere

Packaging Bottle: UN-certified dangerous goods cartons in compliance with ADR

Delivery time within EU: maximum 14 days

If you are interested in our electrolyte, please send us an inquiry to contact@e-lyte-innovations.de or use our contact form:

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Working principle of supercapacitors

Supercapacitors, ultracapacitors or electrochemical double-layer capacitors are widely applied energy storage devices. Comparable to a battery, they consist of two electrodes and an electrolyte. Both technologies are often used complementary due to their individual merits regarding energy density (batteries) and high power (ultracapacitors). The energy storage mechanism differs significantly between both technologies. A lithium-ion battery converts electrical energy to chemical energy via redox reactions while a supercapacitor stores energy via a physical process and the formation of double layers. The double-layer formation is an extremely fast process and thus supercapacitors can be charged/discharged very quickly in the timeframe of seconds, enabling high power. Furthermore, they exhibit very long cycle lives (>500,000 cycles) since the physical storage process is highly reversible and ideally, no structural changes occur at the electrodes. The double-layer formation takes place at the electrode/electrolyte interface, therefore, the active materials and the electrolyte must be tailored with regard to each other. Typically activated carbons with high surface areas are applied as active materials for both, the positive and negative electrodes to form a large electrode/electrolyte interface. During the energy storage process electrolyte ions are attracted and adsorbed on the surface of the electrodes, forming Helmholtz double layers. In such double layers electrolyte ions face the electrode with the opposite charge. The operating voltage of supercapacitors can be set freely in theory but is limited by the electrochemical stability of the supercapacitor components, in particular of the stability of the electrolyte. In addition to double-layer capacitors, there are also hybrid capacitors commercially available. Hybrid capacitors possess two electrodes with different characteristics, one like that of a lithium-ion battery (anode) and one similar to that of an ultracapacitor (cathode)

Application fields of supercapacitors

The most widely used electrolytes in supercapacitors are tetraalkylammonium salts, e.g. tetraethylammonium tetrafluoroborate Et4NBF4 that are dissolved in acetonitrile or propylene carbonate. These combinations of salts and solvents enable high ionic conductivities and low viscosities that are highly important for fast double-layer formations, i.e. high power. Various approaches are currently investigated to increase the voltage of supercapacitors from around 2.8 V today to above 3.0 V with the help of novel electrolytes. Due to their large electrochemical stability window, electrolytes containing ionic liquids are promising alternatives for use in high voltage applications. However, ionic liquids generally have higher viscosities and lower ionic conductivities than the currently used standard electrolytes based on acetonitrile or propylene carbonate. For the use in ultracapacitors, an increased viscosity and lower conductivity are disadvantageous with regard to power density. Ionic liquids can be used as a mixture with organic solvents or as “solvent-free” electrolytes.