Understanding the role of Co3O4 on stability between active hierarchies and scaffolds: An insight into NiMoO4 composites for supercapacitors

Abstract 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 NiMoO 4 nanosheet arrays (NSAs) on free-standing substrates after introducing Co 3 O 4 hierarchies. Under sonication vibration environment, the mechanical stability of Co 3 O 4 @NiMoO 4 NSAs was enhanced by ∼70% compared to that of the pure NiMoO 4 ones. Moreover, the Co 3 O 4 @NiMoO 4 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 Co 3 O 4 @NiMoO 4 core/shell NSAs, while only 70% for the pure NiMoO 4 ones.