Tubular cone-shaped Ni-based anode-supported solid oxide fuel cells (SOFCs), with yttria-stabilized zirconia (YSZ) electrolyte and La0.8Sr0.2MnO3 (LSM) cathode, were investigated with Fe catalyst-loaded activated carbon directly filled in as fuel. Three identical single cells were operated at different current and it turned out that larger current resulted in shorter operation life and smaller carbon utilization. A 3-cell-stack, with the segmented cone-shaped cells connected in series, was assembled and tested. A peak power density of 465 mW cm(-2) and a volumetric power density of 710 mW cm(-3) were achieved at 850 degrees C. The degradation performance was analyzed according to the electrochemical characterization and SEM-EDX measurement. Based on the experimental results, the potential of developing such direct carbon SOFC into a high performance battery was proposed. Copyright (c) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.