A highly electroactive polypyrrole with hollow horns in micro/nanometers (h-PPy) is galvanostatically prepared by a template-free approach in p-toluenesulfonate alkaline solution Its electrochemical capacitance properties are characterized to verify its promising applicability for supercapacitors Besides its high specific surface area h-PPy shows unexpectedly good ordering of molecular chain and great conjugation length contributing to high ionic and electronic conductivity These advantages lead to a remark able specific capacitance of 400 F g(-1) and ultrafast charging/discharging capability with a specific capacitance of 274 F g(-1) at the charging/discharging time of even 0 4 s Moreover the micro/nanostructured hollow horns which can tolerate the mechanical stress in charging/discharging process significantly Improve the cycle life of h-PPy so that the capacitance retains 90% after 100 000 continuous cycles All of its distinguishing quality enable h-PPy to be an excellent active material of supercapacitors (C) 2010 Elsevier B V All rights reserved