Hallot Maxime, Caja-Munoz Borja, Leviel Clement, Lebedev Oleg I, Retoux Richard, Avila José, Roussel Pascal, Asensio Maria Carmen, Lethien Christophe
Institut d'Electronique, de Microélectronique et de Nanotechnologies, Université de Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, UMR 8520-IEMN, F-59000 Lille, France.
Réseau sur le Stockage Electrochimique de l'Energie (RS2E), CNRS FR 3459, 33 rue Saint Leu, 80039 Amiens Cedex, France.
ACS Appl Mater Interfaces. 2021 Apr 7;13(13):15761-15773. doi: 10.1021/acsami.0c21961. Epub 2021 Mar 25.
LiNiMnO (LNMO) is a promising 5V-class electrode for Li-ion batteries but suffers from manganese dissolution and electrolyte decomposition owing to the high working potential. An attractive solution to stabilize the surface chemistry consists in mastering the interface between the LNMO electrode and the liquid electrolyte with a surface protective layer made from the powerful surface deposition method. Here, we show that a 7400 nm thick sputtered LNMO film coated with a nanometer-thick lithium-ion-conductive LiPO layer was deposited by the atomic layer deposition method. We demonstrate that this "material model system" can deliver a remarkable surface capacity (∼0.4 mAh cm at 1C) and exhibits improved cycling lifetime (×650%) compared to the nonprotected electrode. Nevertheless, we observe that mechanical failure occurs within the LNMO and LiPO films when long-term cycling is performed. This in-depth study gives new insights regarding the mechanical degradation of LNMO electrodes upon charge/discharge cycling and reveals for the first time that the surface protective layer made from the ALD method is not sufficient for long-term stability applications.
LiNiMnO（LNMO）是一种很有前景的用于锂离子电池的5V级电极，但由于工作电位高，存在锰溶解和电解质分解的问题。一种稳定表面化学性质的有效解决方案是通过强大的表面沉积方法制备的表面保护层来控制LNMO电极与液体电解质之间的界面。在此，我们展示了通过原子层沉积法沉积了一层涂覆有纳米厚锂离子导电LiPO层的7400nm厚溅射LNMO薄膜。我们证明，与未保护的电极相比，这种“材料模型系统”能够提供显著的表面容量（1C下约0.4mAh/cm），并具有更长的循环寿命（提高了650%）。然而，我们观察到，在进行长期循环时，LNMO和LiPO薄膜内部会发生机械故障。这项深入研究为充放电循环时LNMO电极的机械降解提供了新的见解，并首次揭示了通过ALD方法制备的表面保护层不足以用于长期稳定性应用。
