In order to improve the capacity of hydrogen storage using activated carbon nanofibers, metal and fluorine were introduced into the activated carbon nanofibers by electrospinning, heat treatment, and direct fluorination. The pore structure of the samples was developed by the KOH activation process and investigated using nitrogen isotherms and micropore size distribution. The specific surface area and total pore volume approached 2800 m(2)/g and 2.7 cc/g, respectively. Because of the electronegativity gap between the two elements (metal and fluorine), the electron of a hydrogen molecule can be attracted to one side. This reaction effectively guides the hydrogen molecule into the carbon nanofibers. The amount of hydrogen storage was dramatically increased in this metal-carbon-fluorine system; hydrogen content was as high as 3.2 wt%. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.