In our studies, gate electrodes were placed in mid-position between the anode and the cathode of electrolytic capacitors.  Ionic currents were made to flow through these gate electrodes.  The gate was an electronic p-n junction and consisted of p-type and n-type functionalized carbon nanotubes (CNT).  Chrono-potentiometry and electrochemical impedance spectroscopy revealed the effect of the gate electrode on the overall cell's capacitance.  Current-Voltage measurements (I-V curves) were made on dry samples, which were consisted of p-type and n-type CNT layers.  These data clearly exhibited an electronic diode-like gate characteristics.  Cyclic voltammetry (CV) with two-electrode system configuration was carried out at room temperature and using 1 M NaCl as an electrolyte. 

The electrolytic cell capacitance was assessed while biasing the gate voltage in the range of -15 mV to +15 mV.  This small bias was enough to substantially increase the cell capacitance. 

[1]   Y. Zhang, H. Grebel, “Controlling Ionic Currents with Transistor-like Structure”, ECS Transactions 2 (18). 2007

[2]   S. Sreevatsa, H. Grebel, “Carbon Nanotube Structures as Ionic Barriers: A New Corrosion Prevention Concept”, ECS Transactions 19 (29) 91-100. 2009

[3]   T. Chowdhury and H. Grebel, "Effect of Gate Electrode in Electrochemical Cells", Session B01: Energy Storage: Batteries and Supercapacitors, Abstract MA2015-01 721, 227 ECS Annual Meeting, Chicago, IL, (May 2015).