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