High performance ultra-high molecular weight polyethylene nanocomposite separators with excellent rate capabilities designed for next-generation lithium-ion batteries

Abstract

The separator is a key part of lithium-ion batteries (LIBs), which avoids physical contact between electrodes and keeps the transportation of ions. Continuous efforts have been adopted to modify separators to increase safety and improve electrochemical performance. Combining the industrialized biaxial stretching technique with the electron beam irradiation (E.B) cross-linking method, the advanced nanocomposite separator with great commercialization potential is developed using ultra-high molecular weight polyethylene (UHMWPE) and inorganic silicon dioxide (SiO2) nanofillers. The E.B irradiation cross-linking improves the thermal properties and electrochemical performances of the UHMWPE-SiO2 nanocomposite separator (M2). The modified nanocomposite separator has an outstanding electrolyte uptake (575%) and excellent ionic conductivity (1.60 mS cm−1). And the E.B cross-linked nanocomposite M2 separator can withstand higher current densities (e.g. 116.7 mAh g−1 at high C-rate 8C) than the non-cross-linked version. Current work offers a sustainable and industrialized method for producing advanced separators to improve LIBs' safety and stability.