With Spacelink Inc. working on the electric double-layer capacitor (EDLC), a new capacitor that is equivalent to lithium-ion batteries in terms of energy density can become a reality.
The EDLC includes a single-layer carbon nanotube (CNT) and metal oxide to make the energy density reach to 150 Wh/L. The main areas that EDLC can be used are the regenerative braking system in a vehicle or the power storage unit of a drone, as they need to be quickly charged and discharged.
Spacelink Inc. currently has products that have 55 Wh/L energy density; yet, thee products do not have metal oxide in them. It was found that metal oxide can be added to the electrodes to increase the energy density to the levels of a Li-on battery’s energy density.
Although the product itself is called a capacitor, due to the metal oxide in the oxidation-reduction reaction, the EDLC is a pseudo capacitor.
In the capacitor, single-layer CNTs that were produced by Zeon Corp. were used. The CNTs hold an important role in increasing the energy density and improve other values.
For example, the capacitance is 650 F, the volume is 0.52 L, the mass is 500 g, and the energy density is 58 Wh/kg. These values are all great indicators of an efficient pseudo capacitor. Regarding the CNT and the test results, Spacelink said:
“CNT has a strong cohesive force. When it is simply mixed with liquid and dried, the sheet is solidified. As a result, electrolyte does not sink into the sheet, and it cannot be used as an EDLC. We realized an electrode that does not cohere CNT but makes CNT appropriately entangled.”