Nanoparticles-enabled low temperature growth of carbon nanofibers and their properties for supercapacitors

Car­bon nanos­truc­tures are of great inter­est for a vari­ety of appli­ca­tions, but their cur­rent pro­cess­ing through­put lim­its their indus­tri­al full scale deploy­ment. This paper presents a cost effec­tive and sim­ple fab­ri­ca­tion process, where ver­ti­cal­ly aligned car­bon nanofibers are grown using DC-PECVD at CMOS com­pat­i­ble tem­per­a­tures from cat­alyt­ic nanopar­ti­cles, spin-coat­ed from sta­ble poly­mer-nanopar­ti­cle col­loidal sus­pen­sions. Two dif­fer­ent cat­a­lysts, Co and Cu, are inves­ti­gat­ed by grow­ing car­bon nanofibers at tem­per­a­tures rang­ing from 390 °C to 550 °C, using sus­pen­sions with var­i­ous con­cen­tra­tions of nanopar­ti­cles. The length and mor­phol­o­gy of the grown nanofibers are exam­ined using SEM and the elec­tri­cal prop­er­ties are inves­ti­gat­ed using elec­tro­chem­i­cal mea­sure­ments on sam­ples arranged as super­ca­pac­i­tor devices. Ver­ti­cal­ly aligned CNFs are suc­cess­ful­ly grown from both types of cat­a­lyst. The Co-derived fibers are long and arranged in a denser car­pet-like struc­ture, while the Cu-derived fibers are short­er and in a spars­er for­ma­tion of free-stand­ing indi­vid­ual fibers. All elec­tro­chem­i­cal mea­sure­ments show typ­i­cal super­ca­pac­i­tor behav­iour even at high scan rates of 200 mV/​s , with the fibers grown from Co show­ing great increase in capac­i­tance over the bare chip ref­er­ence device, includ­ing the sam­ples grown at 390 °C.