Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7705508 | International Journal of Hydrogen Energy | 2018 | 10 Pages |
Abstract
Semiconductors have been successfully demonstrated as the electrolytes for solid oxide fuel cells (SOFCs) in recent years. Many such semiconductors have shown their potentials as a competent ionic conductor for fuel cell operation, indicated by the appreciable ionic conduction and electrochemical performance. In the present study, we depart from traditional electrolyte concept to introduce a new semiconductor electrolyte, Li-doped ZnO to low-operating-temperature SOFCs. The used material was synthesized via a co-precipitation method and investigated from phase structure, morphology and UV-vis absorption perspectives. Utilizing Li-doped ZnO as electrolyte layer, we found the corresponding fuel cell exhibited a remarkable maximum power density of 443 mW cmâ2 along with open circuit voltage (OCV) of 1.07 V at 550 °C, and represented a lower-temperature operation feasibility with power outputs of 138-165 mW cmâ2 at 425-450 °C. Besides, high ionic conductivities of 0.028-0.087 S cmâ1 and low activation energy of 0.5 eV were also found in the synthesized Li-doped ZnO at 425-550 °C. Our investigation in terms of electrochemical impedance spectra (EIS) analysis manifested that Li-doped ZnO as the electrolyte layer boosted the electrode reactions of the device, which resulted in rather small polarization resistances and eventually realized good low-temperature performances. Further study based on the rectification characteristic of Ni/Li-doped ZnO contact verified the Schottky junction formation of Li-doped ZnO with anodic Ni, which can avoid the underlying electronic short-circuiting problem. These findings show a profound significance of using doped semiconductor for the future exploitation of SOFC electrolytes.
Related Topics
Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Chen Xia, Zheng Qiao, Liangping Shen, Xueqi Liu, Yixiao Cai, Yang Xu, Jinli Qiao, Hao Wang,