Exceptionally simple and cost-effective solid-state method is reported for the synthesis of different mixed transition metal oxides (MTMOs).including FeCo2O4, MnCo2O4 and ZnCo2O4 with unique nanostructures. The morphological analysis show that MTMOs possess distinct nanostructures such as tetragonal, spherical nanoparticles and hexagonal nano sheets. Furthermore, these MTMOs showed excellent supercapacitive properties with specific capacitances of 660-1263 F/g at current density of 2 A/g. Asymmetric capacitor was fabricated with FeCo2O4 as positive and activated carbon as negative electrode which exhibits a specific capacitance of 88 F/g with energy density of 24 Wh/kg (1.1 mWh/cm(3)) and cycle life (93%) over 5000 cycles. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.