SiO2-assisted co-assembly of ultrafine aramid nanofiber-based porous thermal-resistant separator for Lithium-ion batteries

The separator serves as a critical component in guaranteeing the electrochemical safety and operational reliability of lithium-ion batteries (LIBs). The aramid nanofiber (ANF) membrane-based separator is seen as a promising element for next-generation high-performance LIBs separators. However, the short-range intermolecular interactions within the network of ANFs lead to a highly entangled, extremely dense structure and a lack of porosity. In this study, a novel organic-inorganic separator was prepared in-situ by anchoring well-dispersed SiO 2 nanoparticles on the surface of ANFs. The diameter of the ANFs was reduced by retarding their oriented aggregation with SiO 2 , thereby effectively enhancing the porosity of the separator. The thermal stability and flame retardancy of the hybrid separators were significantly improved by the incorporation of SiO 2 ; moreover, the growth of Li dendrites on the anode surface was effectively suppressed compared with the pure ANFs and the commercial PP separators. The assembled LiFePO 4 /Li battery exhibits exceptional rate capability and stable cycling performance. The ANFs hybrid separator holds great potential as a candidate for high-performance LIBs.