Ionic transport of proton-conducting ammonium vanadate salt in blends of polyvinyl alcohol and sodium alginate for electrochemical applications

Exploring highly foldable batteries with no safety hazard is a vital task for the realization of portable, wearable, and implantable electric devices. Owing to these concerns, developing solid-state batteries is one of the most promising routes to achieve this aspiration. Because of the excellent flexibility and process ability, Sodium alginate blends polyvinyl alcohol-based electrolytes possess great potential to pack high energy density flexible batteries, however, suffers the various intrinsic shortcomings such as inferior ionic conductivity, a high degree of crystallinity, and lack of reactive groups. In this present work, polymer electrolyte films based on NaAlg blend PVA doped with NH₄VO₃ salt were prepared by solution casting method. X-ray diffraction (XRD) explains that the enhancement of conductivity is affected by the degree of crystallinity. Fourier transform infrared (FTIR) spectroscopy analysis confirms the interaction between polymers and salt. For NaAlg/PVA system, a sample containing 15 wt% of NH₄VO₃ possesses the highest ionic conductivity of 0.67 × 10^{- 5} S cm^{- 1}. Several electrical and electrochemical characteristics of the prepared electrolytes were examined, including impedance, dielectric behavior, transference number, electrochemical stability window, energy density, specific capacitance (Cs), and power density. The ionic conductivity of the synthesized solid biopolymer electrolyte (SBE) system was found to be influenced by ion mobility (µ) and the diffusion coefficient (D). Hence, the aforementioned results indicate that the developed SBE system holds strong potential for application in electrochemical energy storage and conversion devices such as proton batteries, supercapacitors, and fuel cells.