A review on recent status and challenges of yttria stabilized zirconia modification to lowering the temperature of solid oxide fuel cells operation

Abstract

Solid Oxide Fuel Cells (SOFCs) are an electrochemical energy converter that receives the world's attention as a power generation system of the future owing to its flexibility to consume various types of fuels, low emission of greenhouses gases, and having high efficiency reaching over 70%. A conventional SOFCs operates at high temperature, typically ranges between 800 to 1000°C. SOFCs use yttria-stabilized zirconia (YSZ) as the electrolyte, which exhibits excellent oxide ion conductivity in this temperature range. However, this temperature range poses an issue to SOFCs durability, as it leads to the degradation of the cell components. In addition, SOFCs application is limited and difficult to implement for the transportation sector and portable appliance. A viable solution is to lower the SOFCs operating temperature to intermediate (600 to 800°C ) or low (<600°C) operating temperature. The benefit of this way, cell durability will improve, as well as other advantages such as facilitates handling, assembling, dismantling, cost reduction, and expanded the SOFCs application. Nonetheless, the key challenge for the issue is finding suitable electrolyte, as YSZ have lower ionic conductivity at low and intermediate temperature range. The aim of this paper is to review the status and challenges in the attempts made to modify YSZ electrolyte within the past decade. The resulting ionic conductivity, microstructure, and densification, mechanical and thermal properties of these 'new' electrolytes critically reviewed. The targeted conductivity of modification of YSZ electrolyte must be exceeded >0.1 S cm -1 to enable high performance of SOFCs power generation systems to be realized for transportation and portable applications. Based on our knowledge, this paper is the first review which focused on the recent status and challenges of YSZ electrolyte towards lowering the operating temperature.

Electrode and Electrolyte Materials From Atomistic Simulations: Properties of LixFEPO4 Electrode and Zircon-Based Ionic Conductors

“…Zirconium-based ceramics have been shown to posses interesting ion-conduction characteristics (Diazguillen et al, 2008;Mandal et al, 2008;Xia et al, 2010;Anithakumari et al, 2016;Li and Kowalski, 2018), with yttria stabilized zirconia being one of the fastest ionic conductors (Kilo et al, 2003;Krishnamurthy et al, 2005b). It is thus used as solid electrolyte in various energy storage devices (Zakaria et al, 2020). The fast oxygen conduction properties are associated with formation and distribution of vacant sites (in fluorite and pyrochlore, Bukaemskiy et al, 2021) and interesting short-and long-range ordering phenomena (Wuensch, 2000;Yamamura, 2003;Anithakumari et al, 2016;Drey et al, 2020;Kowalski, 2020;Bukaemskiy et al, 2021).…”

“…The formed solid solution shows very high ionic conductivity that increases significantly with dopant amount (Ioffe et al, 1978;Bukaemskiy et al, 2021). These compounds are thus considered as solid electrolyte for energy storage devices (Zakaria et al, 2020).…”

Fuel cells as an advanced alternative energy source for the residential sector applications in Malaysia

“…Besides, the high operating working temperature leads to recycling heat waste for the cogeneration energy production system. 74,75 SOFCs run at reasonably high temperatures from 500 C to 1000 C. to high-temperature activity. 76,77 The advantages of hightemperature SOFC are a spectrum of energy usage due to directly reforming internal fuels such as methane and tar.…”

Carbonate dual-phase improves the performance of single-layer fuel cell made from mixed ionic and semiconductor composite

“…Single-layer fuel cell (SLFC) is an intriguing innovation that consists of one homogenous mixed layer of an ionic conductor and a semiconductor. It has been shown to include all the necessary functionalities of a fuel cell in this single-layer [1] [8], whereas conventional fuel cells, such as solid oxide fuel cells (SOFCs), require a three-layer structure with two electrodes and an electrolyte [9][10] [11]. The SLFC utilizes nanocomposite materials and nano-redox reactions [1] [2] [3] and may operate below 600 o C, making it easier to fabricate and less prone to mechanical stresses.…”