Transition metals doped BiPO4 nanostructures for energy storage applications

Among the various electrode materials being researched for energy storage, one that has excellent properties is bismuth phosphate. We investigated the electrochemical properties of bismuth phosphate (BiPO4) nanostructures doped by transition metals (Ni, Cu, and Zn) synthesized using the microwave method. The structural and morphological data confirm the existence of the hexagonal phase of the synthesized samples. The FESEM and HRTEM techniques have been used to study the morphology of the samples. Transition metals are utilized as doping materials to enhance the electrochemical features of prepared working electrodes for supercapatterybased storage applications. Doped working electrodes demonstrated a high potential window of 1.4 V. The potential window plays a crucial role during the redox reactions in the electrodes and electrolytes. Cyclic voltammetry (CV) study signifies a diffusion-controlled process, and the observed peaks correspond to the oxidation-to-reduction transition of various valence states of bismuth ions. Ni-doped bismuth phosphate Nanostructures showed the highest specific capacity value, i.e., 411 Cg-1 at 2 Ag-1 current density. The values of specific capacity decreased continuously with the current density. During the stability test, 89% retention capacity was obtained over 3000 charge-discharge cycles.