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Study Overview

In this study, the influence of atomic layer deposition (ALD) derived Li-Al-O interphases in garnet-type Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) solid-state electrolyte (SSE) was investigated. Garnet-type SSE are prone to lithium dendrite growth along interfaces, which causes short-circuits, significantly reducing cell performance. ALD offers high control over coating chemistry and morphology to precisly modify these interfaces in SSEs. Here, Al₂O₃ ALD coatings were applied on LLZTO powder. MAS NMR, XPS and STEM analysis reveal the formation of a compositionally graded Li-Al-O interphase upon deposition due to proton-exchange-induced lithium diffusion. During high-temperature sintering, the ALD coating induces densification and considerable interdiffusion with LLZTO, resulting in a multi-phase microstructure which can be directly controlled via the ALD process, as confirmed by XRD, SEM and EDS measurments. Electrochemical testing reveals that medium-thickness coatings (~ 6.8 nm, 25 ALD cycles) yield optimal performance, exhibiting ionic conductivity at room temperature of 0.39 mS/cm with good Li-dendrite resitance and long-term cycling stability.

Dataset Description

This dataset contains NMR, XPS, XRD, Ellipsometry, EDS line scans, and electrochemical measurements to investigate Li-Al-O interphases in LLZTO.

The dataset is organized into the following folders:

NMR

²⁷Al Solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy experiments were performed using an AvanceNEO spectrometer (Bruker). Data are stored in the folder NMR.

XPS

X-ray photoelectron spectroscopy (XPS) measurements of the Al 2p and C 1s region were conducted using a NEXSA G2 spectrometer (Thermo Fisher Scientific). Data are stored in the folder XPS.

XRD

X-ray diffraction (XRD) experiments were recorded using an Empyrean diffractometer (Pananalytical). Quantitative phase analysis (QPA) on the XRD diffractograms were conducted using the software package Diffrac.Topas version 7 (Bruker). The corresponding diffractograms and fitting data are stored in the folder XRD.

Ellipsometry

Ellipsometry data were recorded using a FS-8 spectroscopic ellipsometer (Film Sense LLC). Data are stored in the folder Ellipsometry.

Electrochemistry

Electrochemical impedance spectroscopy (EIS), critical current density (CCD) measurements, long-term plating/stripping experiments and chronoamperometry (CA) measurements were performed. Data are stored in the folder Electrochemistry.

EDS line profile

EDS line profiles were recorded using a FEI Titan G2 80-200 CREWLEY system. Data are stored in the folder EDS_line_profile.