A practical Li-ion full cell with a Li-ion conductor coating cathode and graphite anode: Strong interface stability and superior electrochemical performance

LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523) was coated by a lithium-ion conductor Li₃PO₄ layer using a pre-coating treatment and solid state method. The physicochemical characteristics were investigated by XRD, SEM, TEM and XPS. Li₃PO₄ coating layer maintained the crystal structure of NCM523 cathode. The cathode with 3.0 wt% Li₃PO₄ coating (P0.03-NCM) exhibited outstanding rate capability (169.3 mAh g⁻¹ at 0.2 C) and cycling retention of 92.23% at 1 C after 150 cycles, whereas the pristine NCM exhibited a capacity retention of only 77.84%. The electrochemical performance of the full-cell (P0.03-NCM as the cathodes and graphite as the anodes) showed high cycle retention of 82.92% after 100 cycles. The Li₃PO₄ coating layer acted as a physical barrier and alleviated the degradation behaviors of NCM523. This research work provided insights for the commercial application of ternary layered cathodes.