Synthesis of conducting polymer intercalated sodium vanadate nanofiber composites as active materials for aqueous zinc-ion batteries and NH₃ gas sensors at room temperature

Among the key technologies required for building industrial safety systems is portable integrated safety devices based on gas sensors and rechargeable batteries. In preparation for such integrated devices, this study focuses on the synthesis of sodium vanadate nanofibers (SVNF) and poly(3,4-ethylene dioxythiophene) (PEDOT) intercalated SVNF (E-SVNF) composites by a simple sonochemical approach for room temperature NH₃ gas sensing and zinc ion battery (ZIB) studies. Applying E-SVNF to ZIBs resulted in superior rate capability, with a capacity of 192.13 mAh g⁻¹ at 15 A g⁻¹. Furthermore, they demonstrated long-term cycling stability, maintaining 83.47% of their capacity at 15 A g⁻¹ even after 3,000 cycles. The gas sensor incorporating E-SVNF showcased a high response and excellent selectivity, even at room temperature, with response values of 1.059 for 10 ppm and 1.113 for 70 ppm of NH₃ gas. These remarkable enhancements in the electrochemical performance of ZIBs and the gas sensor are attributed to the insertion of conductive polymers between SVNF layers. This resulted in improved electrical conductivity, increased interlayer distance in the vanadate nanofiber structure, enhanced layered structural stability, increased oxygen vacancies, a decreased work function, and the formation of p-p heterojunctions, all of which contribute to improved functionality of the composites materials. This research is expected to serve as a cornerstone for the development of industrial safety systems.