Imperial College London
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Professor Stephen Skinner

Faculty of Engineering, Department of Materials

CeresPower/RAEng Research Chair in Electrochemical Devices
 
 
 
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Contact

 

+44 (0)20 7594 6782s.skinner

 
 
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Location

 

206GoldsmithSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Shih:2018:10.1016/j.ssi.2018.01.003,
author = {Shih, D and Aguadero, A and Skinner, SJ},
doi = {10.1016/j.ssi.2018.01.003},
journal = {Solid State Ionics},
pages = {32--38},
title = {Improvement of Ionic Conductivity in A-site Lithium Doped Sodium Bismuth Titanate},
url = {http://dx.doi.org/10.1016/j.ssi.2018.01.003},
volume = {317},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Oxide-ion conductors play a significant role in various applications such as solid oxide fuel cells (SOFCs), oxygen separation membranes and sensors. Recently, high ionic conductivity (~ 1 × 10− 4 S cm− 1 at 600 °C) was found in sodium bismuth titanate (NBT), which originates from oxygen vacancies compensating the introduced Bi-deficiency. By providing pathways with low diffusion barriers, the highly polarizable Bi3 + ions with 6s2 lone pair electrons and weak Bisingle bondO bonds are also beneficial for the migration of oxygen ions. Here we report the influence of lithium doping on the electrical properties of NBT. The optimal doping level of 4 at% Li on the Bi-site improves the ionic conductivity by one order of magnitude to ~ 7 × 10− 3 S cm− 1 at 600 °C without changing the conduction mechanism, which could be attributed to an increase in the oxygen vacancy concentration based on an acceptor doping mechanism. A further increase in Li content does not improve the total conductivity. Oxygen diffusion data were acquired by the Isotope Exchange Depth Profile (IEDP) method in combination with Secondary Ion-Mass Spectrometry (SIMS). The oxygen self-diffusion coefficients (e.g. 7.04 × 10− 9 cm2 s− 1 at 600 °C) are in excellent agreement with the values derived from impedance spectroscopy data, suggesting that the oxygen ions are the main charge carriers in the system. Furthermore, a degradation test was performed for 100 h under a variety of atmospheres, showing only a slight decrease in conductivity in both air and oxygen atmospheres attributed to the loss of material from the A-site. Comparison with other oxide-ion conductors indicates that Li-doped NBT materials are promising candidates for intermediate temperature SOFC applications.
AU  - Shih,D
AU  - Aguadero,A
AU  - Skinner,SJ
DO  - 10.1016/j.ssi.2018.01.003
EP  - 38
PY  - 2018///
SN  - 0167-2738
SP  - 32
TI  - Improvement of Ionic Conductivity in A-site Lithium Doped Sodium Bismuth Titanate
T2  - Solid State Ionics
UR  - http://dx.doi.org/10.1016/j.ssi.2018.01.003
UR  - http://hdl.handle.net/10044/1/55642
VL  - 317
ER  -
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