Preparation Of CoB-Graphene And One-Dimensional Co-C Mateials By Ball Milling Method And Their Electrochemical Hydrogen Storage Properties

Hydrogen is one of the most promising future sustainable energy fuels due to its abundance,high energy density,and environmental friendliness.However,the major impediment is that it is difficult to be high-capacity stored within an effective,safe and stable solid-state medium,which restricts its practical application.Hence,the design and synthesis of new hydrogen storage materials with high capacity and excellent cycling stability are extremely desirable.In this paper,we synthesize a series of CoB-graphene and one-dimensional core/shell Co-C hydrogen storage materials through ball-milling methods.The morphology and microstructure of the materials were investigated by SEM,TEM and XRD,etc.In addition,the capacities of hydrogen storage,charge-discharge curves and storage mechanism were studied,respectively.A series of CoB-graphene materials are synthesized by ball-milling method.Frist,different CoB alloys were synthesized in difffernent speed and ball-milling time.Second,in order to investigate the effect of graphene on CoB alloys,we take the ratio between CoB and grapheme at ratio of 2:1,5:1 and 10:1,respectively.And after few hours ball milling process,we get a serials of CoB-graphene samples with mass sandwich-like structure.It shows that the maximum discharge capacity of materials is the one that the ratio is 5:1 and ball-milling time is 10 hours.And the maximum capacity is about 2.87 wt%.A series of one-dimensional CNT/Co and CNF/Co materials are synthesized by ball-milling method.In this work,metal cobalt has been uniformly coated on CNT's and CNF's surfaces in nanoscale through a simple ball milling process.Accordingly their X-ray diffraction,scanning electron microscope and transmission electron microscopy measurements clarify the satisfying composite structures.And their electrochemical experimental results demonstrate that the as-obtained CNT/Co and CNF/Co composites have excellent electrochemical hydrogen storage reversibility and considerably high storage capacities of 2.62 wt% and 2.70 wt%.