Functional modification of polypropylene separators with solid electrolyte LATP and SiO2 coatings for lithium batteries

The separator is crucial to the performance and safety of the battery. This study prepared a polypropylene (PP) /solid electrolyte Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) /SiO 2 composite separator (PP/LATP/SiO 2 ). The experimental results demonstrate significant enhancements in the electrolyte wettability and thermal stability of the separator. Furthermore, the lithium-ion transference number ( t + ) has been raised from 0.22 to 0.56. In electrochemical performance tests, the lithium symmetric battery assembled with the PP/LATP/SiO 2 composite separator exhibits an exceptionally long cycle life, sustaining stable cycling for 900 h at a current density of 0.5 mA cm −2 . This composite separator, combining the solid electrolyte and SiO 2 layer, effectively facilitates lithium-ion transport and reduces the occurrence of electrode side reactions, thereby enhancing the performance and safety of the battery.