Mechanochemically synthesized NiCo2O4/Vulcan/PANI nanocomposite and investigation of its electrochemical behavior as a supercapacitor

Wet-mechanical alloying was used to synthesize NiCo2O4 (Ni-Co) nanoparticles. XRD results showed that single phase nanoparticles were formed after 1 h of milling and a minimum crystallite size of 3 nm was obtained for 3 h-milled sample. The 3-h-milled sample was mechanically alloyed with Vulcan (Vu) to fabricate NiCo2O4/Vulcan (Ni-Co/Vu). The Ni-Co/Vu sample was thoroughly mixed with aniline (ANI), and the mixture was then polymerized to polyaniline (PANI). The microscopic evaluations showed the change in shape of Ni-Co particles from spherical to worm-liked after the polymerization process. Their structure was evaluated using FT-IR and Raman spectroscopies. The electrochemical studies through cyclic voltammetry (CV) and chronopotentiometry (CP) showed the highest capacitance for the 3-h-milled Ni-Co, in comparison with other milled samples. The capacitance of 341 F g−1 of the 3-h-milled sample, was enhanced to 455 and 644 F g−1, upon introducing Vu and Vu/ PANI, respectively

Facile and scalable synthesis of ultrafine MnCo2O4 nanoparticles via mechanical alloying as supercapacitive materials

The possibility of synthesizing MnCo2O4 nanoparticles from MnCl2·4H2O and CoCl2·6H2O via mechanical alloying was investigated and sampled after 1, 2, 3, and 4 h of milling. X-ray diffraction (XRD) analysis showed that the initial materials were changed to MnCo2O4 after 1 h of milling and calcination. The broadening of the XRD lines showed that MnCo2O4 crystallites were on the order of nanometers. Fourier-transform infrared spectroscopy spectra of the MnCo2O4 samples indicated the cation distribution of Co-O (~ 567 cm−1) and Mn-O (~ 665 cm−1) in octahedral and tetrahedral sites, respectively. The morphology of the samples is spherical, according to field emission scanning electron microscopy results. Electrochemical measurements, including cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy, were performed to evaluate specific capacitance, cyclic stability, and charge transfer resistance, respectively. The highest capacitance of about 546 F/g and efficiency of 103% were obtained for the 3-h-milled MnCo2O4 sample