Partially graphitic porous carbon with embedded nickel nanoparticles is prepared by direct carbonization of nickel-organic framework (NiOF). NiOF converts to carbon and NiO after calcination at 400 degrees C in air, while that converts to carbon and Ni at temperature higher than 600 degrees C in nitrogen atmosphere. The calcination temperature influences both the carbon structure and surface area, and consequently determines the capacitive behavior of carbon composite electrodes. Partially graphitic porous carbon with tailored pore size and good electrical conductivity can be achieved at the calcination temperature higher than 600 degrees C. The specific surface area of carbon composite increases with elevating the calcination temperature, it reaches a maximum value at 800 degrees C. A decrease in surface area at temperature higher than 800 degrees C is attributed to the high graphitization degree of carbon. The specific capacitance of carbon composite electrodes comes mainly from the nickel nanoparticles embedded in the porous carbon framework. NiOF after calcination at 800 degrees C shows good cycle-life stability and exhibits the best performance, its specific capacitance reaches 886 F g(-1) at 1 A g(-1) and only decreases to 746 F g(-1) a(t) 30 A g(-1). The significantly improved capacitive behavior results from the porous conductive carbon with macropores that expedites the transport of electron and electrolyte. (C) 2014 Elsevier B.V. All rights reserved.