Exploring the Characteristics of Na1.35CrO4 as Active Electrode for Energy Storage Application in Sodium‐Ion Batteries

For the first time, Na 1.35 CrO 4 is successfully synthesized using a citric acid‐assisted sol–gel method, and its physicochemical and electrochemical properties are explored as an active electrode material for sodium‐ion batteries (SIBs). Extensive physicochemical analyzes confirm the phase purity, high crystallinity, and orthorhombic crystal symmetry of Na 1.35 CrO 4 , having well‐controlled elemental stoichiometry and a smooth surface with nanoparticle morphology. The nanoparticles have an average particle size of 42.87 nm, providing a high active contact surface. Na 1.35 CrO 4 coexists with Cr 6+ and Cr 7+ oxidation states, with Cr 6+ as the dominant one. The electrochemical studies for Na 1.35 CrO 4 as an active electrode are carried out through sodium half‐cells. The cyclic voltammetry reveals an open circuit voltage of about 1.842 V and consistent redox peaks within a working voltage window of 0.01 to 3.0 V, representing the structural and phase stability of Na 1.35 CrO 4 . The power‐law analysis shows battery‐type features and diffusion‐controlled charge transfer for energy storage. The electrochemical impedance spectroscopy analysis indicates good electrolyte compatibility and excellent charge transfer kinetics of Na 1.35 CrO 4 . The material also exhibits a low double layer capacitance, representing its suitability for high‐energy‐density applications. These investigations reveal that Na 1.35 CrO 4 could be a promising electrode for SIBs.