Mechanical Ball-Milling Preparation of Fullerene/Cobalt Core/Shell Nanocomposites with High Electrochemical Hydrogen Storage Ability

Abstract

The design and synthesis of new hydrogen storage nanomaterials with high capacity at low cost is extremely desirable but remains challenging for today's development of hydrogen economy. Because of the special honeycomb structures and excellent physical and chemical characters, fullerenes have been extensively considered as ideal materials for hydrogen storage materials. To take the most advantage of its distinctive symmetrical carbon cage structure, we have uniformly coated C60's surface with metal cobalt in nanoscale to form a core/shell structure through a simple ball-milling process in this work. The X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectra, high-solution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrometry (EDX) elemental mappings, and X-ray photoelectron spectroscopy (XPS) measurements have been conducted to evaluate the size and the composition of the composites. In addition, the blue shift of C60 pentagonal pinch mode demonstrates the formation of Co-C chemical bond, and which enhances the stability of the as-obtained nanocomposites. And their electrochemical experimental results demonstrate that the as-obtained C60/Co composites have excellent electrochemical hydrogen storage cycle reversibility and considerably high hydrogen storage capacities of 907 mAh/g (3.32 wt % hydrogen) under room temperature and ambient pressure, which is very close to the theoretical hydrogen storage capacities of individual metal Co (3.33 wt % hydrogen). Furthermore, their hydrogen storage processes and the mechanism have also been investigated, in which the quasi-reversible C60/Co↔C60/Co-Hx reaction is the dominant cycle process.

Intracell Hydrogen Adsorption–Transmission in a Co2P Solid Hydrogen‐Storage Material

“…To further investigate the hydrogen‐storage ability and mechanism of the Co 2 P nanoparticles, their hydrotreating cycles at a charging/discharging rate of 0.1 C are recorded, as shown in Figure (a). A long and stable charging/discharging plateau appeared at about 0.7/1.4 V, which indicates a balanced hydrogen discharging/charging process . In the cyclic voltammogram shown in Figure (b), cathodic peaks at –1.10 and –1.00 V are due to the P–H bonding and Co ··· H interaction, respectively.…”

Hydrogen ion supercapacitor cell construction and rational design of cell structure

“…In active porous carbon electrode side, the simple double-layer discharge curves were presented, and their capacitance were found to increase as the increasing of the mass loading. In the Co@NMC negative electrode side, however, a quick double-layer discharging followed by a potential plateau, which was believed to relate to the process of electrochemical hydrogen desorption from the Co@NMC, 35,38,[45][46][47][48] were observed. The discharge capacity of the Co@NMC negative electrode was also found to increase with the mass of active porous carbon positive electrode, since the observed capacity of negative electrode must equal to that of positive electrode when the hybrid device is operated.…”

Hybrid Veil-Like Co(OH)2/rGO Nanocomposites Towards Electrochemical Hydrogen Storage Properties

“…The charge plateau is at about 1.44 V in the charge process, which can be attributed to the reaction of Co!Co-H x and the adsorbed hydrogen on the surface of the nan ocomposite. [36][37][38] In the discharge curve, two obvious plateaus are observed at 1.17 V and 0.50 V, which suggests di®erent reaction sites in the nanocomposite. The discharge plateaus appearing at about 1.17 V are comparable to those of other Co-based alloys, which is due to the reaction to the reaction of Co!Co(OH) 2 and the discharge capacity agreeing with the capacity of charging process ($ 160 mAh/ g).…”