Fabrication and Investigation of PE-SiO@PZS Composite Separator for Lithium-Ion Batteries.

Commercial polyolefin separators exhibit problems including shrinkage under high temperatures and poor electrolyte wettability and uptake, resulting in low ionic conductivity and safety problems. In this work, core-shell silica-polyphosphazene nanoparticles (SiO@PZS) with different PZS layer thicknesses were synthesized and coated onto both sides of polyethylene (PE) microporous membranes to prepare composite membranes. Compared to pure silica-coated membranes and PE membranes, the PE-SiO@PZS composite membrane had higher ionic conductivity. With the increase in the SiO@PZS shell thickness, the electrolyte uptake, ionic conductivity and discharge capacity gradually increased. The discharge capacity of the PE-SiO@PZS composite membrane at 8 C rate was 129 mAh/g, which was higher than the values of 107 mAh/g for the PE-SiO composite membrane and 104 mAh/g for the PE membrane.