Materials Science and Engineering Program and ‡Department of NanoEngineering, University of California San Diego , La Jolla, California 92093, United States.
ACS Appl Mater Interfaces. 2017 Aug 9;9(31):26518-26530. doi: 10.1021/acsami.7b05326. Epub 2017 Jul 27.
Atomic layer deposition (ALD) is a commonly used coating technique for lithium ion battery electrodes. Recently, it has been applied to sodium ion battery anode materials. ALD is known to improve the cycling performance, Coulombic efficiency of batteries, and maintain electrode integrity. Here, the electrochemical performance of uncoated P2-NaNiMnO electrodes is compared to that of ALD-coated AlO P2-NaNiMnO electrodes. Given that ALD coatings are in the early stage of development for NIB cathode materials, little is known about how ALD coatings, in particular aluminum oxide (AlO), affect the electrode-electrolyte interface. Therefore, full characterizations of its effects are presented in this work. For the first time, X-ray photoelectron spectroscopy (XPS) is used to elucidate the cathode electrolyte interphase (CEI) on ALD-coated electrodes. It contains less carbonate species and more inorganic species, which allows for fast Na kinetics, resulting in significant increase in Coulombic efficiency and decrease in cathode impedance. The effectiveness of AlO ALD coating is also surprisingly reflected in the enhanced mechanical stability of the particle which prevents particle exfoliation.
原子层沉积（ALD）是一种常用于锂离子电池电极的涂层技术。最近，它已被应用于钠离子电池的阳极材料。ALD 被认为可以改善电池的循环性能、库仑效率并保持电极完整性。在这里，我们将比较未涂层的 P2-NaNiMnO 电极和经过 ALD 涂层的 AlO P2-NaNiMnO 电极的电化学性能。鉴于 ALD 涂层在 NIB 阴极材料的开发初期，对于 ALD 涂层（特别是氧化铝（AlO））如何影响电极-电解质界面知之甚少。因此，本工作对其影响进行了全面的表征。首次使用 X 射线光电子能谱（XPS）阐明了 ALD 涂层电极上的阴极电解质界面（CEI）。它含有较少的碳酸盐物种和更多的无机物种，这使得钠离子具有快速的动力学特性，从而显著提高了库仑效率并降低了阴极阻抗。氧化铝 ALD 涂层的有效性还出人意料地体现在颗粒的机械稳定性增强上，这防止了颗粒剥落。
