Preparation and electrochemical performance of ZrO2 nanoparticle-embedded nonwoven composite separator for lithium-ion batteries

To improve the safety of lithium-ion batteries, a high performance composite separator based on ZrO2 nanoparticles and poly (ethylene terephthalate) nonwoven was successfully prepared. Systematical investigations including morphology characterization, porosity measurement, electrolyte wettability, thermal shrinkage testing, and cell performance examination were carried out. The results show that ZrO2 nanoparticles and nonwoven substrate endow the composite separator with outstanding thermostability, which may lead to improved safety of the batteries. Meanwhile, the composite separator possesses unique porous structure formed between ZrO2 particles. Owing to the relatively polar constituents and well-developed microstructure, the composite separator exhibits higher air permeability and porosity, as well as superior electrolyte wettability compared to the commercialized polyethylene separator. Based on the above advantages, this composite separator shows better electrochemical properties, such as the discharge C-rate capability and cycling performance, as compared to the polyethylene separator. This research presents a simple approach to prepare high performance separator, which is demonstrated to be a good candidate for lithium-ion batteries.