Li ₂ CO ₃ as a Modifier for PVA/PVP/PEG Blend Polymer Electrolytes: Effects on Structural Integrity, Electrical Performance, Thermal Behavior and Optical Properties

Abstract

The effects of incorporating lithium carbonate (Li2CO3) into a polyvinyl alcohol/polyvinyl pyrrolidone/polyethylene glycol (PVA/PVP/PEG) blend polymer electrolyte were investigated. Electrolytes were prepared via solution casting method, with Li2CO3 added at 10, 20, and 30 wt.% to the PVA/PVP/PEG blend (50/30/20 ratio). Fourier transform infrared spectroscopy analysis revealed interactions between the added salt and the polymer blend. The addition of both PEG and Li2CO3 resulted in increased ionic conductivity, reaching a maximum of 4.51 × 10− 5 S/cm at 30°C with 20 wt.% Li2CO3. Ionic conductivity also exhibited a positive temperature dependence. Optical analysis showed a decrease in the optical energy gap with the addition of PEG and Li2CO3. Differential thermal analysis indicated improved thermal stability with increasing Li2CO3 content, as evidenced by higher onset, endset, and midset temperatures. The enhanced properties of the modified electrolyte suggest its potential applicability in lithium-based electrochemical devices.