Core–shell-structured nanofibrous membrane as advanced separator for lithium-ion batteries

Ceramic-layer coated Lithium ion batteries (LIBs) separator shows excellent thermal stability, good electrolyte wettability, but usually poor mechanical strength. For the first time, Silica Encapsulated Nanofibrous Separator (SENS), in which ceramic coating layer is covalently bonded to the polymer nanofibers, is prepared as an advanced composite separator for LIBs. Properties of SENS including morphology, ionic conductivity, electrochemical stability, thermal stability, mechanical strength and battery performance were characterized. Because of the unique SiO2-coating structure and cross-linked three-dimensional network, SENS shows significant advantages of good thermal stability up to 200°C, high ionic conductivity, excellent coating strength and improved battery charge–discharge performance. •SiO2 layer is covalently coated on polymer nanofibers.•SENS has good flexibility and strong adhesion strength of the SiO2 coating layer.•SENS separator shows no shrinkage up to 200°C.•SENS separator has high ionic conductivity and excellent electrolyte wettability.•LIBs with SENS separator shows notably improved battery performance.