Ionic Conductivity and Cycling Stability Improvement of PVDF/Nano-Clay Using PVP as Polymer Electrolyte Membranes for LiFePO4 Batteries

Abstract

In this paper, we present the characteristics and performance of polymer electrolyte membranes (PEMs) based on poly(vinylidene fluoride) (PVDF). The membranes were prepared via a phase-inversion method (non-solvent-induced phase separation (NIPS)). As separators for lithium battery systems, additive modified montmorillonite (MMT) nano-clay served as a filler and poly(vinylpyrrolidone) (PVP) was used as a pore-forming agent. The membranes modified with an additive (8 wt % nano-clay and 7 wt % PVP) showed an increased porosity (87%) and an uptake of a large amount of electrolyte (801.69%), which generated a high level of ionic conductivity (5.61 mS cm⁻¹) at room temperature. A graphite/PEMs/LiFePO₄ coin cell CR2032 showed excellent stability in cycling performance (average discharge capacity 127 mA h g^−minus;1). Based on these results, PEMs are promising materials to be used in Polymer Electrolyte Membranes in lithium-ion batteries.