Unveiling the Role of CeO₂ Atomic Layer Deposition Coatings on LiMn₂O₄ Cathode Materials: An Experimental and Theoretical Study

Abstract

An atomic layer deposition (ALD) coating on active materials of a lithium ion battery is a more effective strategy for improving battery performance than other coating technologies. However, substantial uncertainty still remains about the underlying physics and role of the ALD coating in improving battery performance. Although improvement in the stability and capacity of CeO thin film coated particles for batteries has been reported, a detailed and accurate description of the mechanism has not been provided. We have developed a multiphysics-based model that takes into consideration stress mechanics, diffusion of lithium ion, and dissolution of transition-metal ions of spinel LiMnO cathode. The model analyzes how different coating thicknesses affect diffusion-induced stress generation and, ultimately, crack propagation. Experimentally measured diffusivity and dissolution rates were incorporated into the model to account for a trade-off between delayed transport and prevention of side reactions. Along with experimental results, density functional theory results are used to explain how a change in volume, due to dissolution of active material, can affect battery performance. The predicted behavior from the model is well-matched with experimental results obtained on coated and uncoated LiMnO-Li foil cells. The proposed approach and explanations will serve as important guidelines for thin film coating strategies for various battery materials.

Controllable atomic layer deposition coatings to boost the performance of LiMnxCoyNi1−x−yO2 in lithium-ion batteries: A review

“…Up to now, there have been many studies about ALD coating on the cathodes in LIBs. In previous studies, it was found that the thickness of a single layer coating is not stabilized to a certain number [27,64,66,67,70,76,77,78,79,80,81,82,83,84,85,86]. However, because of its self-limiting nature, the thickness does not increase when the single layer deposition is saturated.…”

“…In addition, TM cations dissolved in electrolyte and volume expansion lead to structural degradation. Mohanty [67] and Zhu [83] successfully stabilized the structure by inhibiting phase transition by ALD coating of titanium oxide and aluminum oxide on the surface of LiMO 2 (M 5 Ni, Co, Mn) and NCM811, respectively. The evidence for suppressing phase transition is shown in the Figs.…”

Recent Advances in Theoretical Development of Thermal Atomic Layer Deposition: A Review

“…Table 2 summarizes the theoretical-study-only ALD articles found in the Web of Science and covered in this review. It is worth mentioning that this review mostly focuses on the theoretical-study-only ALD articles and does not cover the combined experimental and theoretical ones, which are cited here [ 75 , 76 , 130 , 131 , 132 , 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 , 154 , 155 , 156 ]. Figure 5 displays the publications, summarized in Table 2 , that are covered in this study.…”

Surface modification and functionalization of powder materials by atomic layer deposition: a review

“…The improved cell performance was explained by suppression of the impedance rise and facile transport of the species. 117 ALD of CeO 2 was also applied to modify the surface of a Li-rich layered material made from Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LRNMC) particles. 118 Compared with the uncoated LRNMC particles, the surface modified samples showed 8% higher capacity and significantly improved capacity retention after 400 charge–discharge cycles.…”