The Co3O4 nanosheets electrode have been fabricated on Ni foam by a facile synthesis process including the electrodeposition of Co(OH)(2) precursor followed by subsequent thermal transformation of precursor to Co3O4. The resulting Co3O4 nanosheets electrode exhibits an ultrahigh specific capacitance of 6469 F g(-1) at a current density of 5 mA cm(-2), exceeding their theoretical value. Moreover, at density of 15 mA cm(-2), the specific capacitance maintains 4127 F g(-1), with 81.6% retention after 2000 chargedischarge cycles. The work confirms the promising application of Co3O4 nanosheets as an efficient electrode for supercapacitors, and also offers a facile strategy to design and synthesis Co3O4 electrode with enhanced specific capacitance. (C) 2015 Elsevier Ltd. All rights reserved.