On the quantification of hydrogen in lithium metal oxides

Abstract

This article presents different hydrogen sensitive methods to determine the bulk hydrogen content in LiMO3 (M = Nb, Ta).

Hydrogen Diffusion in Li(Nb,Ta)O3 Single Crystals Probed by Infrared Spectroscopy and Secondary Ion Mass Spectrometry

“…This gives an approximate initial hydrogen concentration of c H ≈ 1–3 × 10 18 cm –3 for both types of samples. This is in agreement with values found by other authors on commercial crystals. ,, …”

“…For analysis, the integrated peak area is determined by fitting the data with a Gaussian function. For the absorption strength, we find in the literature values of a OH = 9.1 × 10 –18 cm or a OH = 2.0 × 10 –17 cm for LiNbO 3 and a OH = 2.8 × 10 –17 cm for LiTaO 3 . This gives an approximate initial hydrogen concentration of c H ≈ 1–3 × 10 18 cm –3 for both types of samples.…”

“…with a OH is the absorption strength 25,41 , d ≈ 0.05 cm is the sample thickness and A is the integrated peak area. For analysis, the integrated peak area is determined by fitting the data with a Gaussian function.…”

“…This is in agreement with values found by other authors on commercial crystals. 25,41,42 According to FTIR measurements, the LiNb 0.15 Ta 0.85 O 3 crystal did not contain detectable amounts of OH − absorption and consequently hydrogen because it is grown in argon, containing only 0.8% of oxygen. Using eq 1, an initial concentration below 1 × 10 −17 cm −3 can be assessed.…”

“…A rough estimate can be given following ref on the basis of the FTIR results (see below). From the integrated peak area of the OH – absorbance, E , the initial hydrogen concentration, c H , can be calculated as c H = ∫ E d ν normald a OH = A normald a OH with a OH is the absorption strength , , d ≈ 0.05 cm is the sample thickness and A is the integrated peak area. For analysis, the integrated peak area is determined by fitting the data with a Gaussian function.…”