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

In this study, a facile and low cost free-template hydrothermal precipitation method was used to synthesize mesoporous Ni-Co based bimetallic carbonates (CO3)(2-) and/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 extensively structurally and morphologically. The textural analysis results confirmed the presence of mesoporous products with a BET-SSA similar to 50 m(2) g(-1) (0.52 cm(3) g(-1) pore volume) for the 3D urchin-like structure and a BET-SSA similar to 47.14 m(2) g(-1) (()0.31 cm(3) g(-1) pore volume) was obtained for the 2D nanoflakes structure. The electrochemical measurements performed in a 6.0 MKOH aqueous electrolyte depicted excellent electrochemical performance ascribed to the optimized composition of Ni-Co LDH (or alpha-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 capacitances (capacities) of 1700 F g(-1) (161 mAh.g(-1)) and 1379 F g(-1) (192 mAh.g(-1)) were obtained for both structures at 5 mV s(-1) scan rate (0.5 A g(-1) gravimetric current density) respectively. These are much better than mono - hydroxides synthesized in same conditions with 351 F g(-1) (90 mAh.g(-1)) for Ni and 216 F g(-1) (21.5 mAh.g(-1)) for Co. A good cyclic stability of similar to 98% after 2000 charge-discharge cycles at 30 A g(-1) was recorded depicting their potential as suitable materials for energy storage devices. (c) 2018 Elsevier Ltd. All rights reserved.