Preparation And Electrochemical Hydrogen Storage Properties Of Co-S Electrode Materials

As a kind of green source, nickel-metal hydride is environmentally friendly andlarge capacity. In order to solve tradional source crisis, the development of negativeelectrode materials to increase the hydrogen storage property is the key link. Naturally,cobalt-based electrode materials turn out to be outstanding among various hydrogenstorage materials and are brought into focus for its high hydrogen storage, cyclingstability and high ratio discharge property. In this paper, firstly, ball-milling method areused to preparing Co-S electrode material and composites by using grapheme tomodified Co9S8. Secondly, the paper testes the electrochemical hydrogen storageperformance of the electrode materials. Thirdly, in use of XRD, SEM and TEM,explores how parameters of milling method influenced the compositions, conformation,structures and hydrogen storage capacity. What’s more, electrochemical hydrogenstorage mechanism is studied by means of cyclic voltammetry and XPS.High energy ball-milling method are used to prepare Co-S electrode materialswhich show excellent electrochemical performance and explores how speed and ratio ofball-milling method influenced the hydrogen storage capacity. It is shown that when atthe speed of600rpm as well as at the molar ratio between Co and S of1:0.5, reaction togenerate pure Co9S8has excellent electrochemical performance. Its electrochemicalproperties showed the hydrogen storage capacity of1.79wt%hydrogen, good cyclestability and more than60%level of high ratio discharge property. Future to prepareCo9S8-grapheme electrode materials by using grapheme to modified Co9S8and mainlyexplores how weight ratio of ball-milling method influenced the hydrogen storagecapacity. It is shown that when at the speed of400rpm as well as at the weight ratiobetween Co9S8and grapheme of4:1, reaction to generate Co9S8-grapheme have bestelectrochemical performance. Its electrochemical properties showed the greatesthydrogen storage capacity of3.73wt%hydrogen, which can increase capacity by morethan two times compared with Co9S8. Besides, it is explored that how time ofball-milling influenced the Co-S electrode materials. It is found that the product’sdiffraction peaks become sharp and strengthen with increasing milling time and high energy crystal planes appear to help promote the crystallization process.In this paper, Co9S8was tested the cyclic voltammetry by electrochemicalworkstation and electrochemical hydrogen storage mechanism was studied. It was foundthat Co9S8stored hydrogen by the means of change of hydride and solid solution andsurface adsorption. The modified Co9S8-graphene electrode materials stored hydrogenby the means of changing of Co9S8to hydride and special gap structure. The decreasingof hydrogen storage property is mainly because of the destruction and electrolytecorrosion during charging and discharging.