Improving the safety of an Ah-level energy-dense Li-ion cell by LATP solid electrolyte modified separators

Abstract Modifying separators with inorganic particles represents an effective route to improve their mechanical and thermal stability during abuse conditions but generally affects the cell’s electric performance. This study investigates the implementation and effect of Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 (LATP) solid electrolyte (SE) coated polyethylene (PE) separators on the electric and safety performances of an Ah-level energy-dense (≥300 Wh/kg) Li-ion cell. Compared to traditional coating materials like AlOOH (boehmite), LATP demonstrates a superior candidate that can significantly improve the passing rate of the cell in nail pentation tests to 80% and extend the endurance time of cell in heat box tests by tens of seconds and simultaneously enables improved cycling and rate performances. While the improved cell electric performance could be ascribed to the excellent Li ion conductivity of LATP, the safety improvement could be related to LATP’s beneficial role in enhancing the thermal stability of the separator and the suppressive role on the thermochemical reaction of the Ni-rich cathode.