Two-dimensional graphene nanoplatelets incorporated PEO/PLA polymer mixture for the enhanced electrochemical performance of quasi-solid polymer electrolytes

In this work, a two-dimensional graphene nanoplatelets (GNP) incorporated polymer blend of polyethylene oxide (PEO) and polylactic acid (PLA), employing their advantageous characteristics in gel polymer electrolytes (GPEs), which demonstrate a high ionic conductivity towards the superior electrochemical performance of the lithium metal batteries (LiMBs) is presented. The PLA has excellent thermal and chemical stability, contributing to improved performance and durability of PEO/PLA blend-based GPEs. Lithium perchlorate (LiClO₄) and different wt.% of GNP are incorporated to optimize and enhance the electrochemical properties of the GPEs. The effects of LiClO₄ and GNP on the morphology, thermal properties, and crystallization of GPE polymer blends have been analyzed thoroughly. The electrochemical impedance spectroscopy indicated that the GPE was 2 wt.% GNP has the highest ionic conductivity of 3.61 × 10^{− 4} S/cm with a crystallinity of 27.76%, confirming that adding GNP decreases the resistance and increases the crystallinity of the GPEs to an optimal level for the superior charge storage capacity. Besides, the galvanostatic charge-discharge study has indicated the GPE with 2 wt.% GNP achieved a lithiation capacity of 479 mAhg^{− 1}, with an initial coulombic efficiency of 59.3%, and attained 76.3% of the theoretical capacity of graphite (372 mAhg^{− 1}).