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

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, CeO 2 thin films were deposited to modify the surface of lithium-rich Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LRNMC) particles via ALD. The film thicknesses were measured by transmission electron microscopy. For electrochemical performance, ∼2.5 nm CeO 2 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 CeO 2 -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 CeO 2 thin-film coating was interpreted as being to increase substrate conductivity and to block the dissolution of metal ions during the charge–discharge process.

Enhanced Electrochemical Performance of Li‐ and Mn‐Rich Cathode Materials by Particle Blending and Surface Coating

“…The n‐LMR/Ce cathode shows a discharge capacity of 161.3 mAh g −1 and capacity retention of 84.6 % after 100 cycles. This illustrates that the CeO 2 coating layer is useful for improving the cathode stability, which may be ascribed to the protective CeO 2 layer mitigating oxygen release from the surface and suppressing side reactions with the electrolyte compared to those during the cycling performance of the pristine n‐LMR cathode.…”

“…To suppress the side reactions between the electrode/electrolyte and mitigate the oxygen release from the surface of LMR materials, we use cerium oxide (CeO 2 ) to coat the micron‐ and nano‐sized LMR particles, respectively. The CeO 2 coating materials not only prevent the electrode from being directly exposed to the electrolyte but also have an oxygen storage capability that improves the surface stability of layered oxide materials during the redox reaction (CeO 2 ↔CeO 2−x +x/2O 2 ; x=0−0.5) . On the basis of these efforts, we propose a practical modification strategy by combining micron‐ and nano‐sized particle blending and CeO 2 surface coating modifications to enhance the integral performance of LMR materials, including tap density, rate capability and long‐term cycling life.…”

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

“…Through ALD treatment, a coating layer can be formed on LIB cathode surface, which would protect active materials against erosion from the electrolyte. Similar with the purpose of other coatings [29,63], the main function of the ALD coating layer is to separate electrolyte and active materials, inhibiting the electrolyte corroding the active material, as shown in Fig. 2(c).…”

Surface Modification of Li‐Rich Mn‐Based Layered Oxide Cathodes: Challenges, Materials, Methods, and Characterization

“…Mn K-edge EELS spectral measurements (Figure 8c,d) indicated that the presence of an Al 2 O 3 surface layer suppresses dissolution of Mn ions and thus retards the consequent structural changes. There are reports on the use of ALD processes for coating LMLO materials with other oxides such as TiO 2 [137] and CeO 2 [138] and with phosphates such as AlPO 4 . [139] Similar to ALD, molecular layer deposition (MLD) adopts small and bifunctional organic molecules to build up organic or organic-inorganic hybrid materials.…”