(119c) Enhanced Performance of Li-Rich Layered Cathode By CeO2 Atomic Layer Deposition

Surface modification has been widely considered as an effective strategy to boost cycle-life and enhance conductivity of electrode particles for lithium ion battery. Through atomic layer deposition (ALD), a conformal ultrathin coating with controllable thickness can provide initial protection for surface of active materials. In this work, Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ (LRNMC) was coated with different ALD cycles of CeO₂. The thickness was estimated by transmission electron microscopy (TEM). With the optimal thickness, the electrochemical performance greatly improved, with an initial capacity of 199 mAh/g, and 60.2% capacity retention after 400 cycles of charge/discharge with 1C (1C=250 mA/g) rate at 55℃, compared to uncoated LRNMC (UC) with 184 mAh/g and <22% at the same condition. These results were explained as increase of conductivity and Mn²⁺ dissolution prevention by CeO₂ coating. To support it, polarization behavior was investigated by electrochemical impedance spectroscopy (EIS). AC and DC resistance of active materials was measured by EIS and chronoamperometry (CA) to quantify the improvement of conductivity.