2015 Fiscal Year Research-status Report
高効率・高耐久性SOFC/SOEC電極のための結晶粒界構造と元素組成の最適化
| Project/Area Number |
15K18213
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| Research Institution | Kyushu University |
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Principal Investigator |
ペリー ニコラ 九州大学, カーボンニュートラル・エネルギー国際研究所, 助教授 (90645665)
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| Project Period (FY) |
2015-04-01 – 2017-03-31
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| Keywords | solid oxide fuel cell / electrode / efficiency / durability / optical absorption / thin films / pulsed laser deposition / energy |
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| Outline of Annual Research Achievements |
This project focuses on improving the efficiency and durability of oxygen electrodes used in solid oxide fuel/electrolysis cells. In particular, the impact of grain boundary density and grain boundary chemistry on performance is examined. Grain boundaries can contain different point defect chemistry that impacts how quickly they can take in or release oxygen. They may also be sources or sinks for impurities that impact the durability of the active surfaces.
In FY2015 the following progress was made:
1) Thin film electrodes of Sr(Ti,Fe)O3-x were fabricated by pulsed laser deposition. The impact of processing conditions on microstructure were determined. Microstructures ranging from amorphous to nanocrystalline to single crystal were fabricated, having different grain boundary densities.
2) The concentrations of point defects that control performance have been studied using a novel contact-free optical absorption approach, in situ, on selected thin film electrodes.
3) The operando performance of the thin film electrodes with different grain boundary densities has been studied with this new optical absorption approach. A clear impact of crystallinity on oxygen exchange kinetics has been observed. The impact of grain boundaries on aging is also being studied by this technique.
Future work includes understanding the impact of the grain boundaries on the oxygen transport (diffusivity) in the electrodes as well as the surface exchange kinetics. Then the grain boundaries will be chemically modified to improve performance. New local scanning probe microscopy techniques will be applied.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The research is taking place at the expected pace.
Stage 1, "fabrication of electrodes with tailored grain boundary density and chemistry", has been mostly achieved. (The heterogeneous doping to control chemistry still remains and will be done in FY2016.)
Stage 2, "in situ characterization of surface exchange rates", has been achieved by the novel optical absorption method. (The work function relaxation method work is ongoing and will mostly be attempted in FY 2016.)
Stage 3, "evaluation of stability and corresponding chemistry", has been partially achieved through many aging studies using the optical absorption approach, which studies native electrode surfaces without metal current collectors. (This work is ongoing, and chemical analysis will be targeted in FY 2016.)
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| Strategy for Future Research Activity |
In FY 2016 the plan is:
Stage 1: Also fabricate electrode films with controlled grain boundary chemistry through heterogeneous doping.
Stage 2: Continue the optical absorption studies of oxygen exchange rates. Attempt to also measure oxygen exchange through work function relaxation approach and impedance spectroscopy approach. Collaborate to study oxygen exchange additionally through oxygen tracer exchange and secondary ion mass spectrometry (SIMS) analysis.
Stage 3: Continue the aging studies to evaluate the impact of grain boundaries on electrode stability. Collaborate to study local grain boundary and surface chemistry before and after aging tests.
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| Causes of Carryover |
I will need to spend more on article costs, instrument fees, and materials costs in FY 2016 compared to FY 2015, for the next stage of the research, so I decided to save some of the money for FY 2016.
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| Expenditure Plan for Carryover Budget |
In FY 2016 funds will support the next stages of the work. Article costs include chemicals for the heterogeneous doping, consumables and materials for the work function relaxation measurements and the impedance measurements, instrument time for the collaborative tracer/SIMS measurements, and instrument time for the chemical analysis of electrodes. Additionally halogen gas for the pulsed laser deposition system may be needed in FY 2016. Travel costs include travel to conferences to present the work and to collaborating institutions.
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Research Products
(14 results)
