Browsing by Author "Wang, Baoyuan"

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Advanced LT-SOFC Based on Reconstruction of the Energy Band Structure of the LiNi0.8Co0.15Al0.05O2-Sm0.2Ce0.8O2-δHeterostructure for Fast Ionic Transport
(2021-09-27) Tayyab, Zuhra; Rauf, Sajid; Xia, Chen; Wang, Baoyuan; Shah, M. A.K.Yousaf; Mushtaq, Naveed; Liang, Shi Heng; Yang, Changping; Lund, Peter D.; Asghar, Muhammad Imran
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Formation of a heterostructure of semiconductor materials is a promising method to develop an electrolyte with high ionic conductivity at low operational temperature of solid oxide fuel cells (LT-SOFCs). Herein, we develop various heterostructure composites by introducing a pure ionic conductor Sm0.2Ce0.8O2-δ (SDC) into a semiconductor LiNi0.8Co0.15Al0.05O2 (LNCA) for LT-SOFCs electrolyte. The morphology, crystal structure, elemental distribution, micro-structure, and oxidation states of the composite of LNCA-SDC are analyzed and studied via X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), high resolution-transmission electron microscopy (HR-TEM), high energy dispersive spectrometry, and X-ray photoelectron spectroscopy (XPS). Electrochemical studies found that the optimal weight ratio of 0.5 LNCA-1.5 SDC heterostructure composite exhibits relatively high ionic conductivity (0.12 S cm-1 at 520 °C), which is much higher than that of SDC. The designed composite of LNCA-SDC heterostructures with optimal weight ratio (0.5:1.5) delivers a remarkable fuel cell power output of 0.735 W cm-2 at 520 °C. The formation of the heterostructure and reconstruction of energy bands at the interface play the crucial roles in enhancing ionic conduction to improve electrochemical performance. The prepared composite heterostructure delivers a unique and insightful strategy of electrolyte in advanced LT-SOFCs.
Designing High Interfacial Conduction beyond Bulk via Engineering the Semiconductor-Ionic Heterostructure CeO2-δ/BaZr0.8Y0.2O3for Superior Proton Conductive Fuel Cell and Water Electrolysis Applications
(2022-12-26) Xing, Yueming; Zhu, Bin; Hong, Liang; Xia, Chen; Wang, Baoyuan; Wu, Yan; Cai, Hongdong; Rauf, Sajid; Huang, Jianbing; Asghar, Muhammad Imran; Yang, Yang; Lin, Wen Feng
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Proton ceramic fuel cells (PCFCs) are an emerging clean energy technology; however, a key challenge persists in improving the electrolyte proton conductivity, e.g., around 10-3-10-2S cm-1at 600 °C for the well-known BaZr0.8Y0.2O3(BZY), that is far below the required 0.1 S cm-1. Herein, we report an approach for tuning BZY from low bulk to high interfacial conduction by introducing a semiconductor CeO2-δforming a semiconductor-ionic heterostructure CeO2-δ/BZY. The interfacial conduction was identified by a significantly higher conductivity obtained from the BZY grain boundary than that of the bulk and a further improvement from the CeO2-δ/BZY which achieved a remarkably high proton conductivity of 0.23 S cm-1. This enabled a high peak power of 845 mW cm-2at 520 °C from a PCFC using the CeO2-δ/BZY as the electrolyte, in strong contrast to the BZY bulk conduction electrolyte with only 229 mW cm-2. Furthermore, the CeO2-δ/BZY fuel cell was operated under water electrolysis mode, exhibiting a very high current density output of 3.2 A cm-2corresponding to a high H2production rate, under 2.0 V at 520 °C. The band structure and a built-in-field-assisted proton transport mechanism have been proposed and explained. This work demonstrates an efficient way of tuning the electrolyte from low bulk to high interfacial proton conduction to attain sufficient conductivity required for PCFCs, electrolyzers, and other advanced electrochemical energy technologies.
A facile method to produce TiO2 nanorods for high-efficiency dye solar cells
(2019-10-31) Wan, Jingshu; Tao, Li; Wang, Baoyuan; Zhang, Jun; Wang, Hao; Lund, Peter D.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Highly ordered TiO2 nanorods are considered promising for photoanodes in dye-sensitized solar cells due to their high charge transfer rate of photo-generated electrons, but they often suffer from low specific area, which may lead to a low conversion efficiency. Here, we produce long vertical single-crystalline rutile TiO2-nanorod arrays on fluorine-doped tin oxide conductive glass substrates(FTO)by the hydrothermal method. To further increase the specific area, the TiO2-nanorod arrays are etched in a secondary hydrothermal process by hydrochloric acid. The etching time have a major effect on the nanorod microstructure and on the dye-sensitized solar cells efficiency. The best result is reached with 8 h of etching, which results in a record high conversion efficiency of 11.14 ± 0.12% (certified efficiency 10.3%) under full sunlight illumination (AM 1.5 G, 100 mW/cm2). The record cell has an open voltage of 0.79 V and a short current density of 21.59 mA/cm2. The proposed manufacturing approach of TiO2 nanorods is highly potential for producing high-efficiency dye-sensitized solar cells.
Non-doped CeO2-carbonate nanocomposite electrolyte for low temperature solid oxide fuel cells
(2020-12-15) Jing, Yifu; Lund, Peter; Asghar, Muhammad Imran; Li, Fengjiao; Zhu, Bin; Wang, Baoyuan; Zhou, Xiaomi; Chen, Chunming; Fan, Liangdong
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
CeO2 is an oxygen nonstoichiometric material for the coexistence of redox pair of Ce3+ and Ce4+, even under an oxidizing atmosphere, and its self-doping is fulfilled bases on the multivalence characteristics. It has been served in versatile applications, including fuel cells and catalysis. Excellent electrochemical performances of solid oxide fuel cell (SOFC) have been achieved at intermediate and low-temperature range based on doped cerium oxide electrolyte. In this study, we utilize its self-doping form to prepare core-shell structure bi-phase nano-composite of CeO2 and alkali carbonate (Li2CO3, Na2CO3 and K2CO3) through a two-step synthesis method. SEM, TEM, XRD, and EIS measurements were applied to characterize the morphology, crystal size, the ionic conductivity of the electrolyte, and the electrochemical performance of resulting ceramic fuel cells. An exceptional ionic conductivity of 0.34 S cm−1 was generated at 550 °C in air, significantly different from its insulating property of the perfect CeO2 phase. A power density of 910 mW cm−2 was also achieved as the highest electrochemical performance of a single cell. The multi-ionic conduction behavior of CeO2-carbonate is also discussed. The results reveal an effective approach to develop alternative SOFC electrolyte materials for low-temperature, high-performance energy conversion applications.