E lectrodes for High Temperature and Pressure Alkaline Electrolysis Cells HTPAEC Jens Q Adolphsen jenquidtudk Bhaskar R Sudireddy Vanesa Gil Christodoulos Chatzichristodoulou ID: 794064
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Slide1
Development of Oxygen Electrodes for High Temperature and Pressure Alkaline Electrolysis Cells (HTP-AEC)
Jens Q Adolphsen (
jenqui@dtu.dk
), Bhaskar R. Sudireddy,
Vanesa Gil
, Christodoulos Chatzichristodoulou
(
ccha@dtu.dk
)
Slide2OutlineECerS conference 2017, Budapest2Motivation for the workSelection of materialsElectrochemical activity towards the OERChemical stability of materials at high temperatureProcessing porous LaNi0.6Fe0.4O3 electrodes
2017-07-13
Slide3High Temperature and Pressure Alkaline Electrolysis Cells (HTP-AEC)ECerS conference 2017, Budapest3Mesoporous Electrolyte matrixRecord data from earlier work3.75 A/cm2 at 1.75 V with
η
el
= 85 % (
200ºC
, 20 bar)
C.
Chatzichristodoulou
et al. J.
Electrochem
.
Soc
, 163, 2016
2017-07-13
Slide4Selection of materials for the OERElectrochemical activityElectrochemical stabilityElectronic conductivity4
Activity
Stability
Electrode materials for
t
he
Oxygen Evolution
R
eaction (OER
)
4
OH
-
aq
O
2(g)+2H2O(l)
4e
-
?
Slide5Electrochemical CharacterizationMaterialsConditionsRTP, N2 atmosphere, 1 M KOH, MeasurementsChronopotentiometry at 0.5, 1.0, 2.0, 5.0, 10, 25 and 50 mA·cm-2Amperostatic EIS 5Reference electrode (RHE from Gaskatel)
Working
electrode
(
Au
current collector
)
Counter electrode (Pt mesh)
Separator
LaNiO
3
La
0.97
NiO
3
LaNi
0.6
Fe
0.4
O
3
La
0.97
Ni
0.6
Fe
0.4
O
3
La
2
Ni
0.9
Fe
0.1
O
4
Slide6Electrochemical Characterization6
Slide7Electrochemical Characterization7Materialb (V/dec)
η
(V)
@
10 mA/cm
2
LaNiO
3
0.083
0.38
La
0.97
NiO
3
0.092
0.44
La
Ni
0.6
Fe
0.4
O
3
0.13
0.44
La
Ni
0.6
Fe
0.4
O
3
0.11
0.45
La
2
Ni
0.9
Fe
0.1
O
4
0.079
0.40
IrO
x
[1]
-
0.32
Ni
0.9
Fe
0.1
O
x
[2]
0.030
0.34
Pr
BaCo
2
O5+x [3]~0.07~0.38
[1]
C. C. L.
McCrory
, S. Jung, J. C. Peters, T. F.
Jaramilllo
, J. Am.
Chem
. Soc. 135 (16977-16987), 2013
[2]
L.
Trotochaud
, J. K.
Ranney
, K. N. Williams, S. W.
Boettcher
, J. Am.
Chem
Soc. 134 (17253-17261), 2012
[3]
A.
Grimaud
, K. J. May, C. E. Carlton, Y-L. Lee, M.
Risch
, W. T. Hong, J. Zhou, Y.
Shao
-Horn, Nat.
Commun
. 4 (2439-2445), 2013
Slide8Electrochemical Characterization8
Slide91 µmSample roughness factors9Initial polished surfacePolished surface after electrochemical testing1 µm
1 µm
Sample
R
RMS
(pre) [µm]
R
RMS
(post)
[µm]
LaNiO
3
0.41
0.79
La
0.97
NiO
3
0.44
0.92
LaNi
0.6
Fe
0.4
O
3
0.37
0.68
La
0.97
Ni
0.6
Fe
0.4
O
3
0.38
0.49
La
2
Ni
0.9
Fe
0.1
O
4
0.20
0.81
Slide10Chemical StabilityPorously sintered pellets and as-received powders exposed toconcentrated KOH for a week at 100°C/220°C 10
Slide11Chemical Stability – XRD 11○LaNiO3 ● LaNi0.6Fe0.4O3 Δ La2Ni0.9Fe0.1O4 + La2O3 ♦ LaO(OH) ♠ La(OH)3
*
NiO
□
NiO
(OH
)
♥
Ni(OH)
2
× Fe
2
O3 ◊ FeO(OH) ♣ Fe(OH)2
Slide12Chemical Stability – XRD12○LaNiO3 ● LaNi0.6Fe0.4O3 Δ La2Ni0.9Fe0.1O4 + La2O3 ♦ LaO(OH) ♠ La(OH)3
*
NiO
□
NiO
(OH
)
♥
Ni(OH)
2
× Fe
2
O3 ◊ FeO(OH) ♣ Fe(OH)2
Slide13Processing of LNF electrode layersProcessing of porous structures for the oxygen evolution reaction - 40-50% total porosity - Hierachical porosity macropores & mesoporesOptimization of the microstructure of the porous electrode: - Allow transport of oxygen leaving the pores - Allow transport of OH- species to reactive sitesOptimal pore size distributionPercolating phases (gas, solid)13MesoporosityMacroporosity
Slide14Processing of LNF electrode layers1410 µm200nm
2
00 µm
Slide15Processing of LNF electrode layers1510 µm10 µmTop surface
Cross section
Slide16AcknowledgementsBent F. HansenJeanette KrambechJens ØstergaardKaren BrodersenKjeld B. AndersenLene KnudsenSøren ChristensenSøren P. V. Foghmoes16Thank you for your attention