Hydrogen Absorbing Materials YOSHIDA Lab. M1 Ryusuke Tominaga.
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Transcript of Hydrogen Absorbing Materials YOSHIDA Lab. M1 Ryusuke Tominaga.
Hydrogen Absorbing Materials
YOSHIDA Lab. M1
Ryusuke Tominaga
The purpose of research
The purpose of my research is through creating high-quality Hydrogen Absorbing Materials , to encourage the prevalence of fuel-cell electric vehicle , and thereby to contribute to the energy and environment concern .
fuel-cell electric vehicle「PUYO」
出典: http://www.nikkei.co.jp/news/main/im20071009AS1D0904609102007.html
(( ->) ->) environment concern
The efficiency of fuel-cell electric vehicle is2 times more efficient than that of normal vehicle
(->energy concern)(->energy concern)
No emissions of carbon dioxide
The structure of Fuel cell
What is the Hydrogen Absorbing Materials ?
The Hydrogen Absorbing Materials are the materials that can absorb and emit hydrogen.
The discover : the Philips Eindhoven institution
( Netherlands)
The condition that must be satisfied to be a practical Hydrogen Absorbing system
Can the system contain enough fuel for about 480km drive ranges at one time refilling ?
Can it release hydrogen at rates fast enough to provide the power and acceleration that drier expect on a freeway ?
Can it fill the fuel fast enough at reasonable price ?
Specific material ZnO
Doping H into T0
Formation energy Ef=[E(ZnO:Hx)-{E(ZnO)+0.5*x*E(H2)}]/x
(zincblende)
BC: Bond-centeredAB: Antibonding T: Tetrahedral H: Hexagonal
Condition for calculation
Machikaneyama2002 http://sham.phys.sci.osaka-u.ac.jp/~kkr/
Korringa-Kohn-Rostoker (KKR) Green’s function method
Coherent potential approximation (CPA) Local density approximation (LDA) No lattice relaxationedelt=0.001 Ry,
ZnO zincblende structure Experimental lattice constants are used.
ZnOThe formation energy of H
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 0.2 0.4 0.6 0.8 1
hydrogen concentration
Ener
gyeV
)(
同時ドーピング法 ドープするドナーとアクセプター濃度にアン
バランつけながら、同時にドープする方法。
a)溶解度増大効果
b) キャリア活性率増大効果 c)易動度増大効果
Specific material ZnO
Doping trantion metal into Zn-site Doping H into T0
Formation energy Ef=[(E((Zn,X)O:Hx)-{E((Zn,X)O)+0.5*x*E(H2)}]/x
(zincblende)
BC: Bond-centeredAB: Antibonding T: Tetrahedral H: Hexagonal
Condition for calculation
Machikaneyama2002 http://sham.phys.sci.osaka-u.ac.jp/~kkr/
Korringa-Kohn-Rostoker (KKR) Green’s function method
Coherent potential approximation (CPA) Local density approximation (LDA) No lattice relaxationedelt=0.001 Ry,
ZnO zincblende structure Experimental lattice constants are used.
The formationenergyof H
0
0.2
0.4
0.6
0.8
1
1.2
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
hydrogen concentration
ener
gyev
)(
X=22
X=23
X=24X=25
X=26
X=27
X=28X=29
no- dop
What is the cause ? LDA error ? Can ZnO be Hydrogen Absorbing Materi
als ?
LDA+SIC
‘Pseudopotential-like self-interaction correction scheme’ by Filippetti and Spaldin. We implement the scheme with
KKR-CPA code (MACHIKANEYAMA2002).
Filippetti and Spaldin, PRB 67, 125109 (2003).Akai, PRL 81, 3002 (1998).
Orbital independent potential
ZnVO
Ishida et al., Pysica B 351, 204 (2004).
LDA
SIC
Main peak at EB = 1.8 eV
Condition for calculation
Machikaneyama2002 http://sham.phys.sci.osaka-u.ac.jp/~kkr/
Korringa-Kohn-Rostoker (KKR) Green’s function method
Coherent potential approximation (CPA) ( Self-interaction corrected LDA (SIC-LDA) ) No lattice relaxationedelt=0.001 Ry,
ZnO zincblende structure Experimental lattice constants are used.
Formation energy of H
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 0.2 0.4 0.6 0.8 1
hydrogen concentration
ener
gy(e
V) SicLDA
Other material MgH2
Sumarry The co-doping method is efficient to Zn
O. But the effect is limited . Using SIC-LDA (Self-interaction corrected LDA) Other material ex) MgH2