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Title: Spatial extent of lithium intercalation in anatase TiO{sub 2}

Abstract

Thin smooth anatase TiO{sub 2} films are obtained by electron beam evaporation of reduced TiO{sub 2}. These films show a preferential (004) orientation when deposited on electron beam evaporated amorphous titanium. Electrochemical lithium insertion into these films is studied with several optical and electrochemical techniques. A coloration efficiency of 13 cm{sup 2} C{sup {minus}1} is found, which is twice as high as that reported for TiO{sub 2} films grown by chemical vapor deposition (CVD). Potential-dependent capacitance measurements show that after the extraction of lithium ions has taken place a small region at the surface of the electrode has a much higher dielectric constant than that of the bulk of the electrode. This is explained by the presence of irreversibly trapped lithium ions in the region where a (reversible) phase transformation from anatase TiO{sub 2} to anatase Li{sub 0.5}TiO{sub 2} has occurred. The extent of this region depends strongly on the intercalation potential; values of 7 and 17 nm are found after 2.5 h of intercalation at {minus}1.0 and {minus}1.2 V vs SCE, respectively. The dielectric constant of the modified surface region is found to range between 500 and 900. A scheme is proposed that describes the mechanism of lithium insertionmore » in terms of a moving TiO{sub 2}{vert_bar}Li{sub 0.5}TiO{sub 2} phase front.« less

Authors:
; ;  [1]
  1. Delft Univ. of Technology (Netherlands). Lab. for Inorganic Chemistry
Publication Date:
OSTI Identifier:
696647
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical
Additional Journal Information:
Journal Volume: 103; Journal Issue: 34; Other Information: PBD: 26 Aug 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; TITANIUM OXIDES; THIN FILMS; ELECTRON BEAMS; EVAPORATION; LITHIUM; DIELECTRIC PROPERTIES

Citation Formats

Krol, R. van de, Goossens, A., and Schoonman, J. Spatial extent of lithium intercalation in anatase TiO{sub 2}. United States: N. p., 1999. Web. doi:10.1021/jp9909964.
Krol, R. van de, Goossens, A., & Schoonman, J. Spatial extent of lithium intercalation in anatase TiO{sub 2}. United States. doi:10.1021/jp9909964.
Krol, R. van de, Goossens, A., and Schoonman, J. Thu . "Spatial extent of lithium intercalation in anatase TiO{sub 2}". United States. doi:10.1021/jp9909964.
@article{osti_696647,
title = {Spatial extent of lithium intercalation in anatase TiO{sub 2}},
author = {Krol, R. van de and Goossens, A. and Schoonman, J.},
abstractNote = {Thin smooth anatase TiO{sub 2} films are obtained by electron beam evaporation of reduced TiO{sub 2}. These films show a preferential (004) orientation when deposited on electron beam evaporated amorphous titanium. Electrochemical lithium insertion into these films is studied with several optical and electrochemical techniques. A coloration efficiency of 13 cm{sup 2} C{sup {minus}1} is found, which is twice as high as that reported for TiO{sub 2} films grown by chemical vapor deposition (CVD). Potential-dependent capacitance measurements show that after the extraction of lithium ions has taken place a small region at the surface of the electrode has a much higher dielectric constant than that of the bulk of the electrode. This is explained by the presence of irreversibly trapped lithium ions in the region where a (reversible) phase transformation from anatase TiO{sub 2} to anatase Li{sub 0.5}TiO{sub 2} has occurred. The extent of this region depends strongly on the intercalation potential; values of 7 and 17 nm are found after 2.5 h of intercalation at {minus}1.0 and {minus}1.2 V vs SCE, respectively. The dielectric constant of the modified surface region is found to range between 500 and 900. A scheme is proposed that describes the mechanism of lithium insertion in terms of a moving TiO{sub 2}{vert_bar}Li{sub 0.5}TiO{sub 2} phase front.},
doi = {10.1021/jp9909964},
journal = {Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical},
number = 34,
volume = 103,
place = {United States},
year = {1999},
month = {8}
}