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Electrochemical Conversion of Natural Gas to Value Added Chemicals
Published in Jianli Hu, Dushyant Shekhawat, Direct Natural Gas Conversion to Value-Added Chemicals, 2020
Wei Wu, Anne Gaffney, Dong Ding
Typical oxygen ion conducting materials are used in SOFC technology including yttrium-stabilized zirconia (Wu et al. 2014; de Souza, Visco, and De Jonghe 1997) and gadolinium doped ceria (Wu, Guan, and Wang 2015; Wachsman and Lee 2011). During operation, oxygen is reduced to oxygen ions at cathode side and transferred across the electrolyte to the anode. At the anode side, ethane is firstly dehydrogenated to ethylene, electrons and protons are combined with oxygen ions to form water, while electrons go through external circuit to produce electricity. This process can also be described as a chemical/power co-generation procedure in an ethane fueled solid oxide fuel cell. Unfortunately, no oxygen ion conducting fuel cell system was reported to be techonomic viable in conversion of ethane to ethylene. There are two major problems inhibiting further development of the EODH technology: first, the presence of oxygen sources at anode side could significantly lead to undesirable deep oxidation of ethane and/or ethylene to carbon dioxide. Second, O-SOCs typically operate at temperatures above 750°C and results in severe side reactions including thermal cracking (Froment et al. 1976) and decreases the C2H4 selectivity. Hibino et al. constructed three kinds of ionic conductors (protonic, oxide ionic and their mixed) to control the oxidative dehydrogenation of ethane at 700 °C (Hibino, Hamakawa, and Iwahara 1993). After comparison, they found the EDH based on P-SOCs presented the highest current efficiency. When P-SOCs were incorporated into the EDH process, the case was shift to nonoxidative mode, namely SO-ENDH.
Component fabrication techniques for solid oxide fuel cell (SOFC) – A comprehensive review and future prospects
Published in International Journal of Green Energy, 2022
Alagu Segar Deepi, Srinivasan Dharani Priya, Arputharaj Samson Nesaraj, Anburaj Immanuel Selvakumar
Magnetron sputtering and electron beam evaporation were also used as PVD techniques. Smolyanskiy et al. deposited La0.6Sr0.4CoO3-δ (LSC) thin films by pulsed DC magnetron sputtering at the oblique angle of the LSC target (Smolyanskiy et al. 2018). The effect of post-annealing temperature in the range of 600–1000°С on the film crystalline structure was investigated. Anode-supported solid oxide fuel cells (SOFCs) with bi-layered thin-film YSZ/gadolinium-doped ceria (GDC) electrolyte and an LSC thin film interlayer were fabricated. Among various fabrication processes, sputtering has shown superior characteristics especially for nanostructured electrode fabrication and does not require high temperatures. The bounded performance of sputtered Ni-based anodes and lack of a basic knowledge of nanostructure control remain significant issues. Wonjong Yu et al. controlled the sputtering deposition angle and rotation speed of the substrate significantly, which improved the in-plane connectivity of the nanostructured Ni anode, resulting in a 50% enhancement in the peak power density of the cell (Yua et al. 2020).
A polymer-assistant for novel semiconductor-ionic membrane solid oxide fuel cells
Published in International Journal of Green Energy, 2022
Wenwen Xu, Wei Yan, Gang Han, Yuzheng Lu
Zhu et al. (2011a) produced an electrolyte-free fuel cell (EFFC) by using a single component of lithium nickel oxide and gadolinium doped ceria, also called a three in one device (Zhu 2011). A maximum power density of 450 mW cm−2 was obtained by this new device at 550°C. To explore the mechanism of this all new SOFC, Zhu et al. (2014) group also invented semiconductor-ionic membrane fuel cells (SIMFCs), meaning that the electrolyte materials were composed of semiconductor, e.g. Sm0.5Sr0.5CoO3 (Deng et al. 2017), LaSrCoFe-oxide (Wang et al. 2017), La0.6Sr0.4Co0.2Fe0.8O3−δ (Wang et al. 2016), Ni0.8Co0.15Al0.05LiO2−δ (Zhang et al. 2016) and ionic conductor materials, e.g. Ce0.8Sm0.2O2-δ (Deng et al. 2017), Sm and Ca co-doped ceria (Wang et al. 2016; Zhang et al. 2016), Gd doped ceria (Chen et al. 2019), etc. This is different from Mott transition in SmNiO3, reported by Zhou et al. (2016), which occurred in semiconductor materials SmNiO3 under a fuel cell condition. There is a balance between semiconductor and ionic conductor materials, which results in high ionic conductivity while prohibiting electron transport through the electrolyte membrane.