Effect of surfactant on the morphology and capacitive performance of porous NiCo2O4

Abstract

A promising nickel cobaltite oxide (NiCo 2 O 4 ) composite electrode material was successfully synthesized by a sol-gel method and followed by a simple sintering process. The microstructure and surface morphology of NiCo 2 O 4 modified by hexadecyltrimethylammonium bromide (CTAB) and polyvinyl alcohol were physically characterized by powder X-ray diffraction and scanning electron microscopy. Meanwhile, electrochemical performance was widely investigated in 2 M KOH aqueous electrolyte using cyclic voltammetry, galvanostatic charge-discharge test, and electrochemical impedance spectroscopy. The results show that evident porous microstructure was successfully fabricated by CTAB. The NiCo 2 O 4 controlled by CTAB exhibited highly specific capacitance of 1,440 Fg −1 at a current density of 5 mAcm −2 . Remarkably, it still displays desirable cycle retention of 94.1 % over 1,000 cycle numbers at a current density of 20 mAcm −2 . The excellent electrochemical performance suggests its potential application in electrode material for electrochemical capacitors.

NiCo2O4-based materials for electrochemical supercapacitors

“…Since this pioneering work, several researchers have been devoted on this sol-gel approach. [61][62][63][64][65] The typical preparation process is illustrated in Fig. 5a and the mechanism of gelation can be explained by the following reaction sequence in which M represents nickel or cobalt ions, and A À represents Cl À or NO 3 À ions.…”

“…By using citric acid as the chelating ligand and H 2 O-DMF as solvent via a facile sol-gel process, the submicron-sized NiCo 2 O 4 particles exhibited a specic capacitance of 217 F g À1 with a high mass loading of 5.6 mg cm À2 . While Kong et al 61 developed a sol-gel process by adding different surfactants, such as hexadecyltrimethylammonium bromide (CTAB) and polyvinyl alcohol (PVA), to control the microstructure and surface morphology of the NiCo 2 O 4 nanoparticles. The product modied by CTAB shows the highest specic capacitance of 1440 F g À1 at a current density of 5 mA cm À2 .…”

“…Both of them show remarkable electrochemical performances. Note that surfactants, 19,50,56,61,62 such as hexadecyltrimethylammoniumbromide (CTAB), polyvinyl alcohol (PVA), and citric acid, have also been studied extensively, which contribute to the formation of unique morphologies and excellent electrochemical performance. Moreover, the sonochemical precipitation technique, 83 chemical bath deposition, 84 co-precipitation method 85,86 and single-spinneret electrospinning technique 87 have also been utilized to synthesize NiCo 2 O 4 nanostructures for supercapacitors.…”

Surfactant assisted sonochemical synthesis of Bi2WO6nanoparticles and their improved electrochemical properties for use in pseudocapacitors

“…Among all, H2 possess a higher value of specic capacitance value. Recently, Kong et al 52 reported on the effect of surfactants (CTAB and PVA) and their concentration on the morphology and capacitive performance of porous NiCo 2 O 4 . The specic capacitance was enhanced from 1063 F g À1 to 1440 F g À1 and 1263 F g À1 for 0.025 g CTAB and 0.075 g PVA.…”

Progress in Spinel‐Structured Cobaltite‐Based Positive Electrode Materials for Supercapacitors

“…Thus the morphology and microstructure of NiCo 2 O 4 controlled by CTAB possess higher specific capacitance with capacity retention of about 94.1 % over 1000 cycles. [33] Meanwhile, Ye Qin Wu and his coworkers stated that apart from processing parameters, the initial molar concentration, reaction time, and solvent too plays a critical role in preparing targeted products. Using citric acid as a chelating agent and H 2 O-DMF as a solvent, they created NiCo 2 O 4 coral-like porous crystals, sub-micron sized NiCo 2 O 4 particles, and NiCo 2 O 4 nanoparticles through Sol-gel.…”