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Page 10 of 14 Chen et al. Energy Mater. 2025, 5, 500064 https://dx.doi.org/10.20517/energymater.2024.163

Figure 5. Origin of the enhanced performance enabled by ALD strategy. (A) Comparison of EIS spectra of LMA-
Alucone|LLZO/PEO/LiTFSI|Alucone-NCM811 and LMA|LLZO/PEO/ LiTFSI|NCM811 batteries after 50 cycles at 0.1C, 50 °C. (B) PDF of
the LLZO/PEO/LiTFSI film before and after cycling in the LMA-Alucone|LLZO/PEO/LiTFSI|Alucone-NCM811 battery. (C) XAS of Ni
-
L-edge of NCM811 (without ALD coating) and alucone-coated NCM811 cathodes. Normalized COO signal from TOF-SIMS on the
surface of (D) NCM811 and (E) alucone-coated NCM811 cathodes after cycling. (F) SEM images of Li metal surface after 50 cycles of
the (i) LMA-Alucone|LLZO/PEO/LiTFSI|Alucone-NCM811 battery and (ii) LMA|LLZO/PEO/LiTFSI| NCM811 battery.

PDF, XAS, ToF-SIMS and SEM were further employed to check the interfacial products for those two
batteries on the cycled cathodes. The purpose of these characterization is to see if there is any damage to the
NCM811 from cathode reaction or lithium dendrite growth to the electrolyte. The PEO portion of the
LLZO/PEO/LiTFSI film from the battery with alucone coating layer is known to be amorphous, at which
normal XRD cannot detect any diffuse scattering. Therefore, to examine the potential bonding of LLZO/
PEO/LiTFSI film with the alucone coating layer, the total scattering experiment coupled with PDF was used.
The result of PDF also shows negligible changes to the LLZO/PEO/LiTFSI film in LMA-Alucone|LLZO/
PEO/LiTFSI|Alucone-NCM811 batteries [Figure 5B], which indicates that the LLZO/PEO/LiTFSI is
successfully preserved due to the functional role of the alucone coating layer.

The cathode materials were dissembled from the batteries and subject to XAS characterizations. Figure 5C
shows the Ni L-edge of the cathodes from LMA|LLZO/PEO/LiTFSI|NCM811 and LMA-Alucone|LLZO/
PEO/LiTFSI|Alucone-NCM811 batteries. The valence state of Ni can be evaluated by the ratio of the peaks
located at ~852 and 856 eV. Higher ratio of the peaks of alucone-coated NCM811 after cycling indicates the
low oxidation of Ni in the pristine NCM811 [55,56] . In comparison, the cycled LMA|LLZO/PEO/LiTFSI|
NCM811 battery shows a much lower ratio of the peaks which indicates that Ni has been partially oxidized
due to the cycling .
[57]