Effect of post-annealing on structural, optical and electrochemical properties of LiNiVO4 thin films deposited by spray pyrolysis technique

Abstract

LiNiVO4 films were deposited by spray pyrolysis technique on flexible stainless steel as substrates. The XRD results confirm the formation of LiNiVO4 in a highly crystalline form with an inverse spinel structure after post-annealing the film at 600 °C. From the SEM analysis, it was found that increasing the annealing temperature resulted in the merging of grain boundaries which leads to the formation of larger grains. The bandgap was determined, demonstrating that higher annealing temperatures result in the decrement of bandgap from 2.52 to 2.38 eV. The electrochemical performance of the prepared films was studied using a three-electrode set-up. The LiNiVO4 film annealed at 600 °C exhibited a specific capacitance of 38 F/g at 0.1 A/g current density in 1 M LiOH as an electrolyte.