Hydrogen from Regenerative Energy Power Sources: pressurised alkaline electrolyser with high efficiency and

wide operating range The EU-Project „RESelyser“

The RESelyser Project is supported by the European Union's Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant

agreement n° [278732]

R. Reissner1, G. Schiller1, E. Guelzow1, Y. Alvarez Gallego2, W. Doyen2, A. Funke3, H. de Bie3, J.R. Bowen 4

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Alkaline water electrolysis – advantages and problems

• Well established technique up to large scale systems • Cheap materials • Gas purity problems at low load and high pressure • Electrode stability when electrolyser off • System adaptation to use with RES

New approaches to solve the problems

• double layer diaphragm with internal KOH supply (“E-bypass membrane”) and adapted cell concept

New approaches to solve the problems

• double layer diaphragm with internal KOH supply (“E-bypass membrane”) and adapted cell concept

• Coated nickel electrodes for low overpotentials and long-term stability with RES load profile. Coating by

plasma spraying

New approaches to solve the problems

• System design adapted to RES power profile

New approaches to solve the problems

Example solar and wind power profile on a cloudy May day in Southern Germany Data source: DLR Stetter, Brinner

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Sola

r irr

adia

tion[

W/m

^2]

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solar irradiance0

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Win

d ou

tput

[MW

h] wind output

First results

Diaphragm: double side coated PP spacer-fabric. First version: •total thickness ca. 2.4 mm. •Zirfon(ZrO2/polymer composite) dual layer, individual layer thickness ca. 0.5 mm. •interposed free electrolyte channel, 1.4 mm.

2.4 mm

Internal electrolyte

by-pass

Zirfon® layer 1 0.5 m

m

Zirfon® layer 2

CATHODE

ANODE

Cathodes coated with NiAlMo (Raney-Nickel with Mo) for reduced overpotentials and increased stability

First results

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Nickel-punchedhole sheet

NiAlMo alloycoated

current density [A/cm^2]

Ove

rpot

entia

l [m

V]

Cathodes coated with NiAlMo (Raney-Nickel with Mo) for reduced overpotentials and increased stability XPS-spectra a) newly coated b) activated c) after long operation

First results

binding energy / eV540 538 536 534 532 530 528

inte

nsity

a)

b)

c)

binding energy / eV82 80 78 76 74 72

inte

nsity

a)

b)

c)

Al 2p O 1s

Cathodes coated with NiAlMo (Raney-Nickel with Mo) for reduced overpotentials and increased stability Pore size analysis of VPS- coated and activated NiAlMo electrode 3D SEM measurements planned to see evolution of the pore size distribution

First results

• Anodes coated with NiAl (Raney-Nickel) and various Perowkites and Spinell structure oxides.

• NiAl for electrical conductivity and high surface, oxides for increased oxygen production activity

• Preparation by plasma spraying, activation by leaching out the Al

First results

Summary

• DLR, VITO, Hydrogenics and DTU join their know

how and forces to overcome the problems of gas purity and variable load operation of high pressure, low cost liquid alkaline water electrolysers

• The project RESelyser will run until October 2014 • First steps towards improved diaphragms and

electrodes could be demonstrated