Controllable synthesis of a flower-like superstructure of nickel metal-organic phosphate and its derivatives for supercapacitors

Abstract In this study, nickel metal-organic phosphate (Ni-MOPh) (C6H5O3NiP•H2O) was synthesized using a simple method, yielding a three-dimensional (3D) flower-like superstructure composed of layered nanosheets. An amorphous Ni-MOPh derivative [A-(Ni-MOPh)-D] was obtained by calcining Ni-MOPh in air at 600 ℃, which retained the 3D hierarchical superstructure of the precursor and produced uniform pores. Simultaneously, the lattice energy of amorphous materials is low, which is beneficial for ions to enter and exit from the particles, resulting in rapid and reversible chemical intercalation/de-intercalation or redox reactions. In addition, Ni (II) in A-(Ni-MOPh)-D has higher electron binding energy and is more prone to redox reactions. These characteristics render A-(Ni-MOPh)-D suitable as an electrode material for supercapacitors. Following testing, A-(Ni-MOPh)-D showed good electrochemical performance not only in the traditional three-electrode system but also in aqueous devices composed of activated carbon.