Fig.1

Schematic illustration for the structure of Al2O3/PAALi composite separator（A）[13]; Schematic illustration and proposed mechanism of the preparation process of the Al2O3-CGS（B）[14];The behavior of thermal shrink of the PP,PI and Al 2O3-PI se-parators at various temperature（C）[15];The diagrammatic dra-wing of preparation of the Al2O3/PAN separator and LIB assem-bling（D）[16];Distribution of PVDF-TrFE and Al2O3nanoparticles in the electrospun fibers（E）[17] "

Fig.2

Surface and cross-section morphologies of（a,c）PE/AlOOHNPs,（b,d） PE/AlOOHNWhs（A）[22];C-rate performance of Li/LiCoO2 cells containing different separators（B）[24] "

Fig.3

Illustration process for the fabrication steps of TiO2 @PI via the surface-alkaline-etching and in-situ complexation hydrolysis strategy（A）[27];Schematic of the LBLD treatment for construction of TiO2@PI nanofiber membranes（B）[28];Schematic preparation process of PP@TiO2（C）[29];On/off function of the as-prepared PVP/TNT separator（D）[31] "

Fig.4

SEM images of（a） surface and（b） cross-section of ST coating separator,（c） surface and（d） cross-section of SP coating separator（A）[37]; B.Scheme of synthetic mechanism for SiO2-PZS nanoparticles[40]; C.SEM images of BC fibers（a） before and（b） after SiO2 encapsulation[43];（D）Schematic representation depict-ing the manufacturing procedure of the Janus separator[48] "