Improving lithium-ion battery performance with attapulgite nanoparticle-modified polypropylene separator

Abstract

The separator is one of the important components of lithium-ion battery, but there are also some problems, such as low porosity, poor wettability and so on. Therefore, it is an important approach to improve the performance of lithium-ion battery by improving the performance of separator. In this paper, the attapulgite nanoparticle was modified onto the polypropylene separator for the first time by the surface covalent method, and the effect of attapulgite nanoparticles on the properties of separator and the performance of lithium-ion battery was studied in detail. Electron microscopy and infrared characterization results have showed that attapulgite nanoparticles were successfully immobilized on the surface of polypropylene separator by covalent reactions. Compared to the original polypropylene separator, the porosity of polypropylene separator modified with attapulgite nanoparticles was improved obviously (38 % VS 78 %). At the same time, the cost of attapulgite nanoparticle has a clear advantage over other studies. Compared to the lithium-ion battery equipped with original polypropylene separator, and the lithium-ion battery equipped with polypropylene separator modified with attapulgite nanoparticles based on the surface covalent reaction method has a better electrochemical kinetic reaction process and lower interfacial resistance. Meanwhile, the polypropylene separator modified with attapulgite nanoparticles could improve the performance of lithium-ion battery obviously (~ 110 %) in different c densities, and a capacity retention of 97.2 % and 87.3 % was gained for the battery modified with attapulgite nanoparticles at 0.5c and 1c respectively.