Construction of flower/polyhedron hierarchical BiVO4/Mo–NiFe−LDH nanocomposite electrode for advanced asymmetric supercapacitors

The development of high-performance nanomaterials has been crucial for the widespread use of supercapacitors. Among these materials, NiFe−LDH shows excellent charge storage capability because of its abundant redox active sites, environmental friendliness and adjustable chemical composition. However, the agglomeration of nanosheets hinders further breakthroughs in LDH electrochemical performance. Therefore, resolving the issue of LDH stacking and designing of hierarchical porous structure are important strategies to enhance LDH performance. Herein, a flower/polyhedron hierarchical structural BiVO4/Mo–NiFe−LDH nanocomposite was obtained using a facile hydrothermal method. Polyhedral BiVO4 was inserted among LDH nanosheets to reduce stacking and agglomeration, thereby exposing more active sites. Furthermore, doping of the Mo element significantly improved the electronic structure and facilitated the transfer of charges. Benefiting from the positive effect of Mo atoms and BiVO4 on the properties of LDH, BiVO4/Mo–NiFe−LDH exhibited superior property with the specific capacity of 248.3 mAh g−1 at 1 A g−1 (40.0 % at 30 A g−1). In addition, BiVO4/Mo–NiFe−LDH and activated carbon (AC) were served as the positive electrode and negative electrode to fabricate asymmetric supercapacitor (ASC). The constructed BiVO4/Mo–NiFe−LDH//AC ASC could store a large energy density (43.6 W h kg−1 at 800.8 W kg−1) and delivered outstanding capacitance retention of 90.1 % after 10,000 cycles at 15 A g−1. The concept designed in this paper contributed novel ideas to the production of materials with superior energy storage properties and facilitated the further promotion of supercapacitors.