Preparation and electrochemical hydrogen storage properties of Co ₉ S ₈ alloy coated with cobalt/graphene composite

Abstract

A facile one-pot reduction process is used to obtain the cobalt/graphene composite (CoRGO). The CoRGO materials exhibit unique reticular globular morphology. Co 9 S 8 hydrogen storage alloy is fabricated via mechanical alloying method. Different amounts of CoRGO are coated on the surface of Co 9 S 8 alloy by ball milling. The electrochemical characterizations of the composites are conducted in the standard tri-electrode system. Ultimately, the CoRGO coated Co 9 S 8 electrode shows preferable performance than the RGO modified alloy (603.6 mAh/g) and original alloy (577.3 mAh/g). As the additive content of CoRGO is 6 wt%, a maximum discharge capacity of 637.5 mAh/g is obtained. Furthermore, the cycle stability and high-rate dischargeability of the electrode are also enhanced. The Co particles in the CoRGO participate in the reversible redox reactions and the graphene provides high conductivity. The CoRGO with distinctive structure and morphology can not only improve the electrocatalytic activity but also increase the specific surface area of Co 9 S 8 alloy. The cobalt and graphene species in the CoRGO composite serve a synergistic effect in further facilitating the hydrogen diffusion, expediting the charge transfer in/on the alloy and improving the corrosion resistance, thus enhancing the electrochemical performance and reaction kinetics of Co 9 S 8 alloy.

Preparation of CO2‐activated Porous Graphene for Enhancing the Electrochemical Hydrogen Storage Properties of Co9S8 Material

“…[18] The reticular globular Co-RGO was prepared by Liu et al using simple one-pot reduction method. [19] The Co-RGO dopant improved the electrochemical activity and corrosion resistance of CoÀ S material. Wang et al studied the effects of RGO doping on electrochemical properties of CoÀ Cu-Si alloys.…”

“…The reticular globular Co‐RGO was prepared by Liu et al. using simple one‐pot reduction method [19] . The Co‐RGO dopant improved the electrochemical activity and corrosion resistance of Co−S material.…”

Synthesis of a Porous CoS2‐CN/MWCNTs Composite Derived from ZIF‐67 for Electrochemical Hydrogen Storage Applications

“…In recently years, a variety of cobalt‐containing materials including Co−B, Co−P, Co−BN and Co−Si, etc. have been evaluated for electrochemical hydrogen storage [3–5] . These cobalt‐based materials possess high theoretical hydrogen storage capacities and exhibit outstanding electrochemical properties.…”

The impacts of nitrogen doping on the electrochemical hydrogen storage in a carbon

“…Among multitudinous hydrogen storage methods, the electrochemical hydrogen storage of carbonbased materials can be carried out directly at or close to ambient conditions, for example, at room temperature and low pressure. [20][21][22][23][24][25][26] Besides, the electrochemical hydrogen storage also possesses the merits of simplicity, reusability and safety. 27 The mechanism of electrochemical storage contains a few steps as described below: [13][14][15]24,[28][29][30][31] I.…”