Superior lithium battery separator with extraordinary electrochemical performance and thermal stability based on hybrid UHMWPE/SiO2 nanocomposites via the scalable biaxial stretching process

Abstract

As a vital part of lithium-ion batteries (LIBs), the separator is closely related to the safety and electrochemical performance of LIBs. Despite the numerous membranes/separators available commercially, their thermal stability and service life still severely limit the efficiency and reliability of the battery. Herein, for the first time, we designed and prepared a hybrid ultra-high molecular weight polyethylene (UHMWPE)/silicon dioxide (SiO2) nanocomposite membrane via a sequential biaxial stretching process. SEM, EDS, ATR-FTIR, WAXS and TGA characterizations offer clear evidence for the successful preparation of UWMWPE-SiO2 nanocomposite membranes. The influence of SiO2 on the structure and properties of UHMWPE membranes was systematically investigated. The presence of SiO2 improves various fundamental properties of UHMWPE separators, such as thermal stability, electrolyte uptake and wettability, ionic conductivity, and electrochemical performance. Thus, obtained lithium-ion batteries have an excellent discharge capacity of 165 mAh g−1 at 0.1 C-rate and 123 mAh g−1 at 5 C-rate and a greater cycling performance over 100 cycles. Thus, this investigation delivers inspiration for the expansion of inorganic-organic nanocomposite separators for next-generation lithium-ion batteries.