Influence of pH on the crystal structure of NiMoO4 nanomaterials and their supercapacitor performances

Three types of NiMoO4 nanomaterials with different morphologies and crystal structures were synthesized by regulating the pH value of the precursor solutions. The corresponding electrochemical performances were also systematically measured. Very interestingly, with increasing of the pH value, the morphologies of NiMoO4 nanomaterials changed from nanorods to nanosheets, and eventually became to nanoparticles. The NiO/MoO3 (NiMo-7) sample, prepared at the pH of 7 in the precursor solution, exhibited highly interconnected porous structure, demonstrating much higher specific surface area and enhanced specific capacitance (1516 F/g) at 1 A/g. The assembled asymmetric supercapacitor NiMo-7//AC also delivered a high energy density of 50.13 Wh/kg at 749.9 W/kg and good cyclic stability with a capacity retention of 76% after 5000 cycles at 10 A/g. These results indicated that the NiMo-7 electrode has a very promising application prospect in electrochemical energy storage.

Automated summary

Three types of NiMoO4 nanomaterials with different morphologies and crystal structures were synthesized by adjusting the pH value of the precursor solutions. The NiO/MoO3 (NiMo-7) sample exhibited highly interconnected porous structure at pH 7, demonstrating higher specific surface area and enhanced specific capacitance. The NiMo-7//AC asymmetric supercapacitor showed high energy density and good cyclic stability, indicating promising application prospects in electrochemical energy storage.