Preparation Of BDD Electrode And Its Super Capacitive Properties

We report nanostructured TiO₂/boron-doped diamond?BDD?/Ta multilayer films and their electrochemical performances as supercapacitor electrodes.The BDD films were grown on Ta substrates using electron-assisted hot filament chemical vapor deposition.Ti metal layers were deposited on the BDD surfaces by radio frequency magnetron sputtering,and nanostructured TiO₂/BDD/Ta thin films were prepared by electrochemical etching and thermal annealing.The successful formation of TiO₂ and Ta layered nanostructures was demonstrated using scanning electron and transmission electron microscopies.The electrochemical responses of these electrodes were evaluated by examining their use as electrical double-layer capacitors,using cyclic voltammetry,and galvanostatic charge/discharge and impedance measurements.When the TiO₂/BDD/Ta film was used as the working electrode with 0.1 M Na₂SO₄ as the electrolyte,the capacitor had a specific capacitance of 5.23 mF cm^-2 at a scan rate of 5 mV s^-1 for a B/C ratio of 0.1% w/w.Furthermore,the TiO₂/BDD/Ta film had improved electrochemical stability,with a retention of 89.3% after 500 cycles.This electrochemical behavior is attributed to the quality of the BDD,the surface roughness and electrocatalytic activities of the TiO₂ layer and Ta nanoporous structures,and the synergies between them.These results show that TiO₂/BDD/Ta films are promising as capacitor electrodes for special applications.Porous boron-doped diamond?BDD?was prepared by hydrogen-argon plasma etching using electrodeposited Ni nanoparticles as a catalyst.The etching process and formation mechanism of porous BDD were investigated by changing the etching time from 30 s to 300 s.Pores were produced due to the C atoms around Ni nanoparticles are easy to react with hydrogen plasma and form methane.With the increase of etching time,the pore size increased,the pore density decreased,and the pore depth first increased and then maintained unchanged.No preferential etching was observed due to the high energy of argon plasma.The electrochemical behaviors of the pristine and porous BDD electrodes were characterized by cyclic voltammetry?CV?,galvanostatic charge–discharge?GCD?and electrochemical impedance spectroscopy?EIS?.The results showed that the porous BDD electrode exhibited high specific capacitance,which is attributed to its high electrical conductivity and large specific surface area.The highest specific capacitance of porous BDD electrode is 9.55 mF cm^-2,which is 22 time higher than that of pristine BDD electrode.The porous BDD electrode demonstrate excellent cyclic stability where lose only 5.3% of the original capacitance after 600 cycles.