< Solid Oxide Fuel Cell >
Fuel cells allow the direct conversion of chemically stored energy into electrical energy by means of electrochemical oxidation of various fuels. Solid oxide fuel cells (SOFCs) are considered to be among the most promising fuel cells.
- Advantage of Solid Oxide Fuel Cells
- Environmentally friendly: low emission, less CO2
- High efficiency.
- Fuel flexibility & Non-Precious metal catalyst.
- High-quality waste heat for cogeneration applications
In SOFCs, an oxygen reduction reaction occurs at the cathode to produce oxygen anions, which then move through a dense oxygen-ion-conducting electrolyte to the anode. Current state-of-the-art technology SOFCs can produce electrical energy with very high efficiency, low emissions, and excellent fuel flexibility at operating temperatures.
- Materials for Cathode applications
■ Layered perovskite, LnBaCo2O5 (Ln = Pr, Nd, Sm, Gd)
· The best cathode materials for intermediate-temperature solid oxide fuel cell
· Rapid oxygen diffusion, surface exchange kinetics and high electrical conductivity
· Layered perovskite (LnBaCo2O5), Ruddlesden-Popper series (Lan+1NinO3n+1)
- Materials for Anode applications
Mixed ionic-electronic conductors (MIECs) have been developed as ceramic anode materials because of their great durability under anodic operating conditions. Their excellent tolerance to carbon coking and sulphur poisoning, especially, could facilitate the efficient operation of the SOFC directly with natural gas. The A-site layered double perovskite materials including mixed valence transition metal cations provide high electrical conductivity and maintain a large oxygen vacancy content, contributing to fast oxygen ion diffusion and good catalytic activity towards fuel oxidations.
< Proton Conducting SOFCs >
Proton-conducting oxides are ideally suited for the electrolytes of intermediate and low temperatures (400~600 oC)-SOFCs because of their low activation energy and high ionic conductivity. In addition, proton-conducting SOFC (H+-SOFC) can avoid water formation, and thus dilution of the fuel, on the anode side during operation because water will form on the cathode side of the cell, which can lead to higher fuel utilization and greater Nernst potential of SOFCs. One of the basic requirements for high-performing H+-SOFC cathode material is the high conductivity of the electron, oxide ion, and proton with the high chemical stability. In this regards, the triple conducting (H+/O2-/e-) oxides (TCOs) effectively extend the electrochemically active site to the entire surface of cathode.
< Solid Oxide Electrolysis >
Solid-oxide electrolyzers (SOEs), which are essentially solid-oxide fuel cells (SOFCs) operated in reverse, are capable of higher water electrolysis efficiency levels compared to solution-based electrolysis cells because they operate at higher temperatures, i.e., around 925 K. The higher operating temperature results in a lower Nernst potential, the thermodynamic potential required for water splitting, and in lower electrode overpotentials.
Metal-air batteries are powered by oxidizing metal with oxygen from the air. The major appeal of the metal-air batteries is the extremely high specific energy, a measure of the amount of energy a battery can store for a given weight.
- Zn-air battery
Fuel Electrode: 2Zn + 8OH− → 2Zn(OH)42− + 4e−
Fluid: 2Zn(OH)42− → 2ZnO + 2H2O + 4OH−
Air Electrode: O2 + 2H2O + 4e− → 4OH−
Overall: 2Zn + O2 → 2ZnO(s) (E0 = 1.59 V)
- Hybrid Li-air battery
Fuel Electrode : 4Li → 4Li+ + 4e−
Air Electrode : O2 + 2H2O + 4e− → 4OH−
Overall: 4Li + O2 + 2H2O → 4LiOH(aq) (E0 = 3.43 V)
< Membrane Reactor >
The production of syngas is one of the most important industrial processes that provides the building blocks used in the production of valuable chemicals. Conventional processes are highly energy intensive due to their endothermic reaction and require an expensive O2 plant to avoid diluting the products. Recently, it has been proposed that ceramic membrane reactors based on mixed ionic and electronic conductors could greatly enhance the efficiency of reactions compared to conventional processes.
< Polymer Electrolyte Membrane Fuel Cell >
- PEMFC is a promising energy transformation technology from chemical energy to electric energy with oxidation of hydrogen and reduction of oxygen.
- PEMFC possesses powerful characteristic, such as low pollution, high power efficiency, low operating temperatures (55-95 oC) and stable power generation.
- We have focused on advanced catalysts for oxygen reduction reaction in cathode using carbon-based materials.