Spray deposition of steam treated and functionalized single-walled and multi-walled carbon nanotube films for supercapacitors

Abstract

Steam purified, carboxylic and ester functionalized single-walled carbon nanotube (SWNT) and multi-walled carbon nanotube (MWNT) films with homogeneous distribution and flexible control of thickness and area were fabricated on polymeric and metallic substrates using a modified spray deposition technique. By employing a pre-sprayed polyelectrolyte, the adhesion of the carbon nanotube (CNT) films to the substrates was significantly enhanced by electrostatic interaction. Carboxylic and ester functionalization improved electrochemical performance when immersed in 0.1 M H(2)SO(4) and the specific capacitance reached 155 and 77 F g(-1) for carboxylic functionalized SWNT and MWNT films respectively. Compared with existing techniques such as hot pressing, vacuum filtration and dip coating, the ambient pressure spray deposition technique is suggested as particularly well suited for preparing CNT films at large scale for applications including providing electrodes for electrochemical supercapacitors and paper batteries.

Compact-designed supercapacitors using free-standing single-walled carbon nanotube films

“…The specific capacitance decreases continually with the increase of scan rate due to progressively less efficient infiltration of ions into the porous films at higher scan rates, a typical behavior of CNT film electrode. 24 At slower scan rates, the diffusion of ions from the electrolyte can gain access to almost all available pores of the film electrodes and the penetration of electrolytic ions into the pores will be a lot deeper, leading to a high specific capacitance. However, when the scan rate is increased, the efficient infiltration of ions into the porous films is progressively lower, and as a result, there is a reduction in capacitance.…”

“…30 The impedance plots can be explained using the equivalent circuit shown in Fig. 6b, 24,39 where R e is the electrolyte resistance, C f and R f are the capacitance and resistance of SWCNT film electrodes, and C dl and R ct are the double-layer capacitance and chargetransfer resistance, respectively; Z w is the Warburg impedance related to the ionic diffusion in the SWCNT films. In Fig.…”

A 2D graphene-manganese oxide nanosheet hybrid synthesized by a single step liquid-phase co-exfoliation method for supercapacitor applications

“…The spray-deposition method has been described in our previous work [29,30] and some details are described in the electronic supplementary information (ESI).…”

A flexible angle sensor made from MWNT/CuO/Cu2O nanocomposite films deposited by an electrophoretic co-deposition process

“…Many types of metal oxide have been used in CNT/metal-oxide composites, such as tin oxide (SnO 2 ) [1], titanium dioxide (TiO 2 ) [2,3], manganese oxide (MnO 2 ) [4], tungsten trioxide (WO 3 ) [5], copper oxide [6,8], ruthenium dioxide (RuO 2 ) [7] and zinc oxide (ZnO) [9]. Many methods have been used to fabricate CNT/metal-oxide composites on substrates; for example, electrospinning [1], filtration [2], drop-coating [3], roll-pressing [4], spin-coating [5], inkjet printing [10], spray deposition [11], aerosol methods [12], electrophoretic deposition (EPD) [13,14], hot-pressing transfer [14] and filtration-wet transfer processes [15]. However, the use of the electrophoretic co-deposition method for the preparation of multi-wall carbon nanotube/cupric oxide/cuprous oxide (MWNT/CuO/Cu 2 O) nanocomposite films on a polyethylene terephthalate (PET) sheet for an angle sensor has not been reported.…”