Supercapacitors with electrical gates

Further increasing the capacitance of supercapacitors is crucial to a large number of applications in energy, communication and sensor fields. Most attention to date was given to the electrodes and the electrolyte with less attention to the separator layer, which in most cases is an electrically insulating membrane. Here we consider an electronically structured separator, which we call the gate. By depositing the separator with permeable layers of p-type and n-type, functionalized single-walled carbon nanotubes (SWCNT) we show that the capacitance of supercapacitors may be increased (in our case, by at least 15%). Additional capacitance increase is achieved for a gate that is biased between −0.1 V and +0.1 V vs Ag/AgCl (in our case, by 15%). The electrical energy, invested in a biased gate is fully captured as stored energy. Implementation to commercial supercapacitors is discussed, as well.