Selenium incorporated sodium vanadate nanobelts as high-performance electrode material for long-lasting aqueous zinc-ion batteries and supercapacitors

Aqueous zinc ion batteries (AZIBs) have received growing attention for comprehensive energy storage owing to their affordability and high safety. Still, cathode materials that usually exhibit low capacity or poor cycling performance have hindered the practical application of AZIBs. Herein, the selenium-incorporated sodium vanadate (NVO@Se) nanobelts (NBs) were synthesized via a single-step hydrothermal method, followed by calcination under N2 flow. As a cathode for AZIBs, the NVO@Se NBs electrode delivered a high discharge capacity of 329.15 mA h g−1 at 2 A/g with ∼ 99 % coulombic efficiency and excellent rate capability (284.89 and 200.21 mA h g−1 at 4 and 5 A/g, respectively). Mechanistic analyses of the intercalation reaction in the NVO@Se NBs after cycleing using ex-situ X-ray diffraction, field-emission scanning electron microscope, and X-ray photoelectron spectroscopy techniques revealed their good structural stability and electrochemical reversibility. Developing interactive properties, the NVO@Se NBs material was also studied as a battery-type electrode for hybrid supercapacitors (HSCs). By sandwiching the NVO@Se NBs and activated carbon, the fabricated HSC exhibited good power and energy density values, along with its verification for practical applications. From all the electrochemical characteristic results, the NVO@Se NBs material has good aspects for AZIBs and HSCs, which makes new prospects for the advancement of materials in energy storage applications.