Electrochemical measurements of 1D/2D/3DNi-Co bi-phase mesoporous nanohybrids synthesized using free-template hydrothermal method

Abstract

Graphical Abstract0 500 1000 1500 2000 65 Highlights  Ni/Co-precursor ratio effect on the template-free hydrothermal growth of carbonate and/or hydroxide nanocomposites.  Ni/Co-content ratio effect on electrochemical performance of Ni-Co based multiphase nanocomposites. 1D/2D/3D architecture microstructures of Ni-Co bi-phase nanohybrids as promising candidates for electrodes in supercapacitor application. AbstractIn this study, a facile and low cost free-template hydrothermal precipitation method was used to synthesize mesoporous Ni-Co based bimetallic carbonates (CO 3 ) 2and/or hydroxides (OH)micro/nanostructures with different morphologies (1D, 2D and 3D) based on variant stoichiometric compositions. The effect of the growth temperature, synthesis time as well as the Ni/Co-precursors ratio on the physico-chemical properties and faradic electrochemical behavior of these products was investigated. The as-obtained bi-phase nanohybrids were characterized using XRD, FTIR, Raman spectroscopy, TGA, FE-SEM and BET analysis. The textural analysis results confirmed the presence of mesoporous products with a BET-SSA arround 50 m 2 .g -1 and a corresponding pore volume of 0.52 cm 3 .g -1 for the 3D urchin-like structure while a BET-SSA of 47.14 m 2 .g -1 (with 0.31 cm 3 .g -1 pore volume) was obtained for the 2D nanoflakes structure.The CV, CD and EIS electrochemical measurements were performed in a 6.0 M KOH aqueous electrolyte. The excellent electrochemical performance recorded could be ascribed to the optimized composition of Ni-Co LDH (or α-Ni(OH) 2 ) with Co 2 (OH) 3 Cl and their unique hierarchical mesoporous nanoflake and urchin-like architectures. In addition, an exceptionally notable specific capacitance (capacity) of 1700 F.g -1 (161 C.g -1 ) and 1379 F.g -1 (192 C.g -1 )was obtained for both structures, respectively, at 5 mV.s -1 scan rate (0.5 A.g -1 gravimetric current density) compared with their better monohydroxides synthesized in same conditions 351 F.g -1 (90 C.g -1 ) for Ni and 216 F.g -1 (21.5 C.g -1 ) for Co. The electrode also showed good cyclic stability of ~98% after 2000 charge-discharge cycles at 30 A.g -1 making them potential materials suitable for fabricating energy storage devices.

Ni/Zn Layered Double Hydroxide (LDH) Micro/Nanosystems and Their Azorubine Adsorption Performance

“…To better understand the composition of the used nanohybrid based adsorbent as well as the existing functional groups that act on the adsorption mechanism, XPS analysis was performed. Figure 3 shows the deconvolution of main asymmetric peaks (Ni 2p , Zn 2p , C 1s , and O 1s ) of high-resolution core-level XPS spectra, using L/G fitting method consistent with the literature data [36,43]. Ni 2p and Zn 2p show that the oxidation state of these elements is mainly based on ions, namely Ni 2+ (or Zn 2+ ) as in previously reported data, which will be very beneficial in our adsorption process [36,44].…”

Morphology-controlled synthesis of a NiCo-carbonate layered double hydroxide as an electrode material for solid-state asymmetric supercapacitors

“…The stretching vibrations of the Ni–O/Co–O and Ni/Co–OH bands are ascribed at 536 and below 500 cm −1 , respectively. 52 This demonstrates the presence of functional groups such as carbonate and hydroxide in the synthesized samples.…”

Electrochemical Measurements of Ni / Graphene based Nanohybrids for Electrochemical Energy Storage “Supercapacitors”

“…Common vibration bands are observed in the first case of 120°C at 3633 cm -1 , [2358-2363 cm -1 ], 2231 cm -1 , 1363 cm -1 , 631 cm -1 and 641 cm -1 . The narrow absorption located at around 3645 cm -1 is ascribed to the -OH in the brucite-like structure [44]. The band around [2358-2363 cm −1 ] corresponds to the bending mode of water molecules [44,45].…”

“…The narrow absorption located at around 3645 cm -1 is ascribed to the -OH in the brucite-like structure [44]. The band around [2358-2363 cm −1 ] corresponds to the bending mode of water molecules [44,45]. The strong absorption band at 2231 cm -1 indicates the presence of impurities C≡N due to the used urea [46].…”