Improved performance of nitrogen-enhanced SrTiO₃ for energy storage devices

Improving electrochemical energy storage devices, such as supercapacitors, significantly depends on advancements in electrode materials. This paper reported the synthesis of nitrogen-doped strontium titanate (N-doped SrTiO₃) by a simple solid-state mixing and calcination technique employing ammonium salts as the nitrogen source. The material's formation was examined using techniques including XRD, XPS, FT-IR, TEM, and nitrogen adsorption/desorption. The XRD patterns confirmed the formation of a perovskite structure with high crystallinity, whereas the TEM images revealed particle aggregation between 100 and 400 nm. The electrochemical characteristics of both undoped and nitrogen-doped SrTiO₃ were evaluated using cyclic voltammetry (CV), Gavlinostatic charge-discharge curves (GCDC), b-value, Dunn method, and cycling. Nitrogen doping caused notable alterations in redox potentials and improved electrochemical activity, indicating changes to the electronic structure of SrTiO₃. N-doped SrTiO₃ demonstrated enhanced electrochemical performance, attaining a specific capacitance of 130 F g^-1 at 1 A g^-1, higher than that of pure SrTiO₃, which measured 80.8 F g^-1. After 5000 cycles at 10 A g^-1, 80% of the electrode's capacitance was retained, demonstrating exceptional rate capability and cycling stability.