Preparation Of Co-C Composites And Their Electrochemical Hydrogen Storage Properties

With the reduction of fossil energy and the aggravation of the environmentalpollution, clean and pollution-free hydrogen energy has become the wordwide focus.However, most electrochemical hydrogen storage materials have some shortages, suchas discharging performance and cycling stability. So, exploiting new materials withhigh discharging capacity and excellent cycling stability is the important researchdirection for the use of hydrogen energy. In this paper, we research theelectrochemical hydrogen storage performance and hydrogen storage mechanism of aseries of Co-C electrochemical hydrogen storage materials synthesized by high energyball mill.(1) A series of cobalt-graphene(GE) hydrogen storage materials are prepared byball milling at the speed of400rpm. The studies have shown that all of the materialshave layer structure. The ball-milled composite can be indexed to hcp-Co-GE whenthe ratio between Co and grapheme is4:1,5:1and6:1, fcc-Co-GE can be detected inthe product when the ratio between Co and grapheme is7:1and8:1. The maximumdischarge capacity of materials reaches771mAh/g. It shows that the metal Co reactswith GE forming crystal phase of Co3C when the speed is higher than400rpm.(2) We take the ball milling speed of600rpm to prepare a series of Co-CNT andCo-CF hydrogen storage materials. The studies have shown that The ball-milledcomposite have one-dimensional structures which are similar to CF or CNT. TheCo-CF and Co-CNT hydrogen storage materials have excellent discharge performanceand their maximum discharge capacities reach739mAh/g and717mAh/g,respectively. High rate discharge capability of Co-CF and Co-CNT hydrogen storagematerials have a higher retention rate (79.0%and85.3%, respectively).