Suppressing transition metal dissolution and deposition in lithium-ion batteries using oxide solid electrolyte coated polymer separator*

The dissolution of transition metal (TM) cations from oxide cathodes and the subsequent migration and deposition on the anode lead to the deconstruction of cathode materials and uncontrollable growth of solid electrode interphase (SEI). The above issues have been considered as main causes for the performance degradation of lithium-ion batteries (LIBs). In this work, we reported that the solid oxide electrolyte Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 (LATP) coating on polyethylene (PE) polymer separator can largely block the TM dissolution and deposition in LIBs. Scanning electron microscopy (SEM), second ion mass spectroscopy (SIMS), and Raman spectroscopy characterizations reveal that the granular surface of the LATP coating layer is converted to a dense morphology due to the reduction of LATP at discharge process. The as-formed dense surface layer can effectively hinder the TM deposition on the anode electrode and inhibit the TM dissolution from the cathode electrode. As a result, both the LiCoO 2 /SiO-graphite and LiMn 2 O 4 /SiO-graphite cells using LATP coated PE separator show substantially enhanced cycle performances compared with those cells with Al 2 O 3 coated PE separator.