Review of solid oxide electrolysis cells: a clean energy strategy for hydrogen generation

Abstract

Hydrogen is an environmentally friendly alternative to conventional fossil fuels and is considered as a renewable energy carrier for meeting the ever-increasing energy demand. Although hydrogen is abundant on earth in the form of compounds such as water, producing molecular hydrogen demands a large amount of energy. A solid oxide electrolysis cell (SOEC) is an electrochemical device which generates hydrogen from various sources. An SOEC uses high temperature (>800°C) to electrolyse water with high efficiency assisted by thermodynamically favoured water splitting that enables large-scale hydrogen production. This review provides a comprehensive overview of the current status in the developments of high-temperature steam electrolysis using a proton- and oxygen-ion-conducting SOEC system for hydrogen production. The present review summarises the detailed approaches for hydrogen production using SOECs, basic principles, challenges in designing hydrogen and oxygen electrodes and electrolytes, and potential solutions to durability issues.

A Review on Synthesis of Methane as a Pathway for Renewable Energy Storage With a Focus on Solid Oxide Electrolytic Cell-Based Processes

“…The electrodes are separated by a dense ion-conducting ceramic membrane. The feed gases, that is, steam or CO 2 or both, are supplied to the cathode where it reacts with electrons provided by an external power supply to produce H 2 and CO, respectively, and oxygen ions, which are transported through an ionconducting electrolyte to the anode, where they combine and release the electrons (e − ) again (Bandi et al, 1995;Zheng et al, 2017;Pandiyan et al, 2019). The electrochemical reactions taking place in the SOECs are given as follows: Cathode i.…”

“…As for the complete substitution of Ni-YSZ, a wide variety of materials such as perovskites, fluorites, and composites have been studied as prospective cathodes for both hydrogen and syngas generation Wang Y. et al, 2019;Jiang, 2019;Pandiyan et al, 2019). Since the key role of Ni in Ni-YSZ is to provide electronic conduction and catalytic activity toward electroreduction, a pertinent alternative is to seek perovskites that can potentially exhibit these two features.…”

“…These challenges are not specific to synthetic methane production but need focused R&D to meet the performance and life targets for SOECs at a realistic price point. These issues are discussed in detail in SOFC reviews (Balachandran et al, 1989;Lessing, 2007;Shaigan et al, 2010;Ebbesen et al, 2014;Mahato et al, 2015;Mah et al, 2017;Pandiyan et al, 2019;Wang Y. et al, 2019), which apply to SOECs as well.…”

Recent Advances in Power-to-X Technology for the Production of Fuels and Chemicals

“…Electrode materials must be ionic and electronic conducting in order to facilitate electron and mass transport as well as to allow the migration of O 2− species (Coutanceau et al, 2018; Arunkumar et al, 2019). In general, electrode materials consist of mixed oxides with perovskite structure.…”

Green Synthetic Fuels: Renewable Routes for the Conversion of Non-Fossil Feedstocks into Gaseous Fuels and Their End Uses

“…The high operating temperatures improve the transport phenomena since the kinetics of electrochemical reactions is faster (lower activation overpotential), the ohmic overpotential decreased, and the diffusion conductivity is enhanced [215]. Main drawbacks are the high-quality steel needed for auxiliary components, slow load following and start up (several hours), and the requirement for continuous operation as suffers the thermal cycles [216]. Therefore, high temperature electrolyzers are not well suited to be coupled with fluctuant and intermittent energy sources.…”