Pseudocapacitor thin Layer for ultra high-power density supercapacitors

Today, most supercapacitors used for AC rectifiers are electric double layer capacitance (EDLC)-based materials. Usually the arrangement of the material on the current collector required many steps to insure fast diffusion of electrolyte in the material layer. This enables low resistance and fast diffusion of ions, which is required at the high 120 Hz frequency signal that goes out of the diode bridge and needs to be rectified by the capacitor. The main obstacle from integration of those technologies in commercial charges is the high cost and elaborate production steps of those electrodes. In our research we are focusing on electrochemical methods for the fabrication of ultra-thin layers of transition metal oxides on nickel foil. These metal oxide layers can store charge through a fast-redox reaction, an order of magnitude higher capacitance than EDLC-materials, resulting in high areal capacitance (~1 mF cm^-2). In addition, the use of thin layers removes diffusion limitation and in a near negligible charge transfer resistance. Using different oxides for the cathode and anode we can increase the voltage windows, which is crucial for the final capacitor embedded in the charger.