It is often reported that pseudocapacitive electrodes' mechanical stability seriously limited their cycling performances in supercapacitors due to their quick fall off the electrode matrix during frequent fast charge/discharge process. In this work, we have demonstrated the mechanical enhancement in hierarchical NiMoO4 nanosheet arrays (NSAs) on free-standing substrates after introducing Co3O4 hierarchies. Under sonication vibration environment, the mechanical stability of Co3O4@NiMoO4 NSAs was enhanced by similar to 70% compared to that of the pure NiMoO4 ones. Moreover, the Co3O4@ NiMoO4 NSAs can display a high specific capacitance of 1476 F g(-1) at the current density of 1 A g(-1), and an excellent rate capability (keeping 81% at 20 A g(-1)). And after 2000 cycles, high capacitance retention of 96% was achieved for the Co3O4@ NiMoO4 core/ shell NSAs, while only 70% for the pure NiMoO4 ones. (C) 2017 Elsevier B.V. All rights reserved.