Enhancement of ionic conductivity and electrochemical stability of PVA/HPMC/PANI/CuSO4 gel polymer for rechargeable batteries electrolytes

Gel polymer electrolytes (GPEs) have drawn a lot of interest due to their special qualities, which include high conductivity that is comparable to liquid electrolytes, excellent mechanical stability, and high flexibility. Using the solution casting approach, we have synthesized copper ion conducting gel polymer electrolyte (GPE) films made of polyvinyl alcohol (PVA) as the polymer host. An ionic salt, copper sulphate (CuSO4), and a plasticizing solvent, PANI/ [BMIM] [BF4] polyionic liquid, were employed. The structural, electrical, and electrochemical properties of the GPE films were carefully examined. The significant XRD crystalline peak decreased and disappeared upon the addition of PANI/[BMIM] [BF4] polyionic liquid, suggesting that PIL is a useful plasticizer for the PVA/HPMC polymers.The conductivity of GPE films was determined by electrochemical impedance spectroscopy measurements. The sample containing 20% CuSO4 salt has the highest room temperature conductivity (σ = 5.11 × 10−3 S/cm). The measurements of transference numbers show that ions are primarily responsible for the transport of these electrolytes. It seems that the working voltage range is high enough to be used as an electrolyte in batteries, based on the results of using linear sweep voltammetry (LSV) and cyclic voltammetry to evaluate the electrochemical stability of the GPE films.