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Lifespan of fuel cells maximized using small amount of metals

Date:
January 18, 2018
Source:
The Korea Advanced Institute of Science and Technology (KAIST)
Summary:
Researchers have described a new technique to improve chemical stability of electrode materials which can extend the lifespan by employing a very little amount of metals. Using computational chemistry and experimental data, the team observed that local compressive states around the Sr atoms in a perovskite electrode lattice weakened the Sr-O bond strength, which in turn promote strontium segregation.
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Fuel cells are key future energy technology that is emerging as eco-friendly and renewable energy sources. In particular, solid oxide fuel cells composed of ceramic materials gain increasing attention for their ability to directly convert various forms of fuel such as biomass, LNG, and LPG to electric energy.

KAIST researchers described a new technique to improve chemical stability of electrode materials which can extend the lifespan by employing a very little amount of metals.

The core factor that determines the performance of solid oxide fuel cells is the cathode at which the reduction reaction of oxygen occurs. Conventionally, oxides with perovskite structure (ABO3) are used in cathodes. However, despite the high performance of perovskite oxides at initial operation, the performance decreases with time, limiting their long-term use. In particular, the condition of high temperature oxidation state required for cathode operation leads to surface segregation phenomenon, in which second phases such as strontium oxide (SrOx) accumulate on the surface of oxides, resulting in decrease in electrode performance. The detailed mechanism of this phenomenon and a way to effectively inhibit it has not been suggested.

Using computational chemistry and experimental data, Professor WooChul Jung's team at the Department of Materials Science and Engineering observed that local compressive states around the Sr atoms in a perovskite electrode lattice weakened the Sr-O bond strength, which in turn promote strontium segregation. The team identified local changes in strain distribution in perovskite oxide as the main cause of segregation on strontium surface. Based on these findings, the team doped different sizes of metals in oxides to control the extent of lattice strain in cathode material and effectively inhibited strontium segregation.

Professor Jung said, "This technology can be implemented by adding a small amount of metal atoms during material synthesis, without any additional process." He continued, "I hope this technology will be useful in developing high-durable perovskite oxide electrode in the future."

The study co-led by Professor Jung and Professor Jeong Woo Han at Department of Chemical Engineering, University of Seoul was featured as the cover of Energy and Environmental Science in the first issue of 2018.


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Materials provided by The Korea Advanced Institute of Science and Technology (KAIST). Note: Content may be edited for style and length.


Journal Reference:

  1. Bonjae Koo, Hyunguk Kwon, YeonJu Kim, Han Gil Seo, Jeong Woo Han, WooChul Jung. Enhanced oxygen exchange of perovskite oxide surfaces through strain-driven chemical stabilization. Energy & Environmental Science, 2018; 11 (1): 71 DOI: 10.1039/C7EE00770A

Cite This Page:

The Korea Advanced Institute of Science and Technology (KAIST). "Lifespan of fuel cells maximized using small amount of metals." ScienceDaily. ScienceDaily, 18 January 2018. <www.sciencedaily.com/releases/2018/01/180118100814.htm>.
The Korea Advanced Institute of Science and Technology (KAIST). (2018, January 18). Lifespan of fuel cells maximized using small amount of metals. ScienceDaily. Retrieved May 29, 2024 from www.sciencedaily.com/releases/2018/01/180118100814.htm
The Korea Advanced Institute of Science and Technology (KAIST). "Lifespan of fuel cells maximized using small amount of metals." ScienceDaily. www.sciencedaily.com/releases/2018/01/180118100814.htm (accessed May 29, 2024).

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