Strictly speaking, supercapacitors are only those named as electric double layer capacitors (EDLCs), which are the ones more widely used industrially. EDLCs are made of activated carbon electrodes and store energy via electrostatic process in which charges are accumulated at the electrode/electrolyte interface through polarization. Thanks to the mechanism of energy storage, EDLCs offer the rapidest charging capacity and the lowest degradation, but they suffer from a low energy density.
Trying to overcome this problem, a new technology called pseudo-capacitors has been proposed and more recently incorporated to the market. As their name indicates, these systems are not exactly supercapacitors, because their operating principle is completely different. These devices are made of transition metal oxides or electroactive polymer electrodes and store energy through surface or bulk (pseudocapacitive) redox reactions, with a very fast charge transfer response, closer to EDLCs.
However, while pseudo-capacitors store more energy than EDLCs, their widespread use has been hampered by their narrow electrochemical voltage window, which is the voltage range where the electrode materials are stable. The most intuitive approach to combine high energy and high-power density within a single device is to combine the different types of energy storage mechanisms. These brings us to the more novel proposed category of hybrid capacitors, capacitors with special and asymmetric electrodes that exhibit both significant double-layer capacitance and pseudocapacitance, such as lithium-ion capacitors.
The development degree of the Gnanomat nanomaterials, together with the testing in energy storage devices and the versatility of these materials make Gnanomat a key-partners of choice to the pseudocapacitor manufacturers.