Biobased phytic acid as a multifunctional structural and electrochemical modifier for high-ionic-conductivity PEO–LiTFSI solid polymer electrolytes

In this study, we showcase a multifunctional biobased phytic acid (PA) additive that is able to function effectively as both a structural and an electrochemical modifier for PEO 12 –LiTFSI solid polymer electrolytes (SPEs). Structural characterization shows that 20 wt% of PA has led to near-complete suppression of the detectable PEO crystalline peaks, which is accompanied by improved mechanical flexibility and increased tensile strength. Electrochemical analysis reveals a more than 34-fold enhancement in ionic conductivity, which is 3.88 × 10 − 4 S cm⁻¹ at 25 °C, and a high ionic transference number of 0.984. Moreover, the electrolyte possesses a widened oxidative stability range of 4.61 V and also demonstrates stable redox behavior in SS/SPE/Li cells. Full-cell tests with the configuration of Li/SPE/LiFePO 4 show very good performance in terms of rate capability and capacity retention throughout the range of 0.1–2 C, and upon returning to the low C-rate, approximately 91% capacity recovery is achieved.