3D walnut-shaped TiO2/RGO/MoO2@Mo electrode exhibiting extraordinary supercapacitor performance

Rational architectural design is the key to improve specific capacitance. Herein, we present a facile one-step hydrothermal process for the fabrication of a TiO2/RGO/MoO2 composite with an unprecedented 3D walnut-shaped hierarchical nanostructure, in which amorphous TiO2 is decorated on the RGO (reduced graphene oxide)/MoO2 surface via a Mo-involved in situ growth route on Mo net (TiO2/RGO/MoO2@Mo). This 3D structure coated with ultrafine arched nanorods is a great breakthrough in electrochemical performances of TiO2- or MoO2-based electrodes as it exhibits an extraordinary areal capacitance of 3927 mF cm(-2) at 3 mA cm(-2) (i.e. 1636 F g(-1) at 1.25 A g(-1)) with only 3.5% capacitance loss after 5000 cycles. Such an excellent performance is benefitted from the following factors: (i) amorphous TiO2 sculptured MoO2 blocky particles supply more active-site accessibility and facilitate the accommodation of volume expansion. (ii) Arched MoO2 nanorods as well as the walnut-shaped spheres of the composite provide electron transfer paths. (iii) RGO is a soft scaffold, which relieves the volume expansion during the charge/discharge processes.