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

Yan Gao; Rajankumar L Patel; Kuan-Yu Shen; Xiaofeng Wang; Richard L Axelbaum; Xinhua Liang

doi:10.1021/acsomega.7b01922

Boosting the Electrochemical Performance of Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ by Atomic Layer-Deposited CeO₂ Coating

ACS Omega. 2018 Jan 24;3(1):906-916. doi: 10.1021/acsomega.7b01922. eCollection 2018 Jan 31.

Authors

Yan Gao¹, Rajankumar L Patel¹, Kuan-Yu Shen², Xiaofeng Wang¹, Richard L Axelbaum², Xinhua Liang¹

Affiliations

¹ Department of Chemical and Biochemical Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409, United States.
² Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, United States.

Abstract

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, CeO₂ thin films were deposited to modify the surface of lithium-rich Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ (LRNMC) particles via ALD. The film thicknesses were measured by transmission electron microscopy. For electrochemical performance, ∼2.5 nm CeO₂ 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 CeO₂-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 CeO₂ thin-film coating was interpreted as being to increase substrate conductivity and to block the dissolution of metal ions during the charge-discharge process.