Structural and Electrochemical Study of Al2O3 and TiO2 Coated Li1.2Ni0.13Mn0.54Co0.13O2 Cathode Material Using ALD |
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Authors: | Xiaofeng Zhang Ilias Belharouak Li Li Yu Lei Jeffrey W Elam Anmin Nie Xinqi Chen Reza S Yassar Richard L Axelbaum |
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Institution: | 1. Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL 60439, USA;2. School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China;3. Energy System Division, Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL 60439;4. Department of Mechanical Engineering, Michigan Technological University, Houghton, MI 49931;5. Department of Mechanical Engineering and NUANCE Center, Northwestern University, Evanston, IL 60208;6. Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, One Brookings Dr., St. Louis, MO 63130, USA |
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Abstract: | Nanolayers of Al2O3 and TiO2 coatings were applied to lithium‐ and manganese‐rich cathode powder Li1.2Ni0.13Mn0.54Co0.13O2 using an atomic layer deposition (ALD) method. The ALD coatings exhibited different surface morphologies; the Al2O3 surface film appeared to be uniform and conformal, while the TiO2 layers appeared as particulates across the material surface. In a Li‐cell, the Al2O3 surface film was stable during repeated charge and discharge, and this improved the cell cycling stability, despite a high surface impedance. The TiO2 layer was found to be more reactive with Li and formed a LixTiO2 interface, which led to a slight increase in cell capacity. However, the repetitive insertion/extraction process for the Li+ ions caused erosion of the surface protective TiO2 film, which led to degradation in cell performance, particularly at high temperature. For cells comprised of the coated Li1.2Ni0.13Mn0.54Co0.13O2 and an anode of meso‐carbon‐micro‐beads (MCMB), the cycling stability introduced by ALD was not enough to overcome the electrochemical instability of MCMB graphite. Therefore, protection of the cathode materials by ALD Al2O3 or TiO2 can address some of the capacity fading issues related to the Li‐rich cathode at room temperature. |
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Keywords: | cathode materials surface modification atomic layer deposition lithium‐ion batteries |
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