Boosting the Electrochemical Performance of Li1.2Mn0.54Ni0.13Co0.13O2 by Atomic Layer-Deposited CeO2 Coating

High Resolution Image Download MS PowerPoint Slide It has been demonstrated that atomic layer deposition (ALD) provides an initially safeguarding, uniform ultrathin film of controllable thickness for lithium-ion battery electrodes. In this work, CeO 2 thin films were deposited to modify the surface of lithium-rich Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LRNMC) particles via ALD. The film thicknesses were measured by transmission electron microscopy. For electrochemical performance, ∼2.5 nm CeO 2 film, deposited by 50 ALD cycles (50Ce), was found to have the optimal thickness. At a 1 C rate and 55 °C in a voltage range of 2.0−4.8 V, an initial capacity of 199 mAh/g was achieved, which was 8% higher than that of the uncoated (UC) LRNMC particles. Also, 60.2% of the initial capacity was retained after 400 cycles of charge–discharge, compared to 22% capacity retention of UC after only 180 cycles of charge–discharge. A robust kinetic of electrochemical reaction was found on the CeO 2 -coated samples at 55 °C through electrochemical impedance spectroscopy. The conductivity of 50Ce was observed to be around 3 times higher than that of UC at 60–140 °C. The function of the CeO 2 thin-film coating was interpreted as being to increase substrate conductivity and to block the dissolution of metal ions during the charge–discharge process.