A large number of carbon nanotubes (CNTs) have been produced commingled in activated mesocarbon microbeads (AMCMBs) activated by potassium hydroxide in a stainless steel container at 900 degrees C, in which an especial buried-protection method with petroleum coke powders was used to protecting the product during activation. The CNTs were found to be about 50 nm in diameter and characteristic length more than 10 mu m. In addition, the AMCMBs/CNTs compound when used for electrode material of electrochemical double-layer capacitors exhibited a specific capacitance of 243 F g(-1) in 6 M KOH aqueous solution. (C) 2009 Elsevier B. V. All rights reserved.