Peculiar physical properties and material synthesis by self-

organization: New Hydrogen Storage Material

June 22-24, 2015

T. Takami and K. Kawamura

Department of Physics, Osaka University

International Conference and Exhibition on

Mesoscopic and Condensed Matter Physics

Outline

2. New material with a one-dimensional space structure

3. Hydrogen uptake and release

1. Introduction & Motivation; self-organization

4. Mechanism of hydrogen storage

Ideal energysource

■inexhaustible■No emission of CO2

Hydrogen Adsorbing Alloys (LaNi5, TiFe, ···)Porous Materials (Carbon, MOFs, ···)

Conventional Hydrogen Storage Materials

OH H + O Electricity

Introduction

Heavy weight, rare metalSmall adsorption amount at room temperature Irreversibility of adsorption/desorptionExothermic upon adsorption

【Problem】

We develop new hydrogen adsorbingmaterial to overcome above problems.

Motivation

Introduction

0.1 nm

1 nm

10 nm

100 nm

1 mm

10 mm

Sca

le

Time

Top-down method

Bottom-up method

Scanning probe microscopy○: processing at the atomic size×: mass production

Fine processing technology○: mass production×: cost, limit of the size

《Materials Science》

Self-organization○: cost, mass production×: not well established

New material

1. Cu(HCO2)24H2O + C5H5N → C12H12CuN2O4Self-

organ

izationCu

C

H

NO

Cu

Look

Unit cell

C12H12CuN2O4

Cross section of 1D space

N

Dire

ctio

n o

f 1D

space

Characterization

Empirical formula C12H12CuN2O4

Formula weight 311.78

Temperature (K) 200

Wave length (Å) 0.71075

Crystal system orthorhombic (Pnma, No.62)

a (Å) 9.7182

b (Å) 14.3322

c (Å) 10.3144

Crystal size (mm3) 0.19 × 0.16 × 0.14

Crystal color blue

Reflections measured 13357

Refinement method Full-matrix least-squares on F2

Goodness of fit on F2 1.17

R1 (Final R index) 0.0401

R index (All data) 0.0430

wR 0.101510 20 30 40

2 (degree)

(a)

(b)

(c)

Inte

nsity (

arb

. units) Single crystal

Powdered sample

Simulation

Single-crystal X-ray analysis

X-ray diffraction

Single crystals

(001)

Hydrogen storage

2.6 wt% hydrogen israpidly adsorbed in thesingle-crystal material atroom temperature.

500 10001500

12345

0Time (s)H

ydro

genation (

wt%

)

500 1000 1500

5

10

15

0

Time (s)

Hydro

genation (

wt%

)

Pressure cell

Pressure cell + sample

296 K, 6.5 MPa

▲ Metal-Organic Frameworks

N. L. Rosi et al., Science 300, 1127 (2003).

3D space

▲ Our material

1D space

(c)

10-2 10-1 100 1010

0.5

1.0

1.5

2.0

2.5

Adsorp

tion w

eig

ht

(wt%

)

Pressure (MPa)

10-2 10-1 100 1010

0.5

1.0

1.5

2.0

2.5

3.0

Adsorp

tion w

eig

ht

(wt%

)

Pressure (MPa)

(b)

(a)

10-2 10-1 100 1010

0.5

1.0

1.5

2.0

2.5

Adsorp

tion w

eig

ht

(wt%

)

Pressure (MPa)

10-2 10-1 100 1010

0.5

1.0

1.5

2.0

2.5

3.0

Adsorp

tion w

eig

ht

(wt%

)

Pressure (MPa)

10-2 10-1 100 1010

0.5

1.0

1.5

2.0

2.5

3.0

Adsorp

tion w

eig

ht

(wt%

)

Pressure (MPa)

Hydrogen uptake and release

Our crystal can reversibly adsorband desorb hydrogen with a goodcapacity.

Conventional Maximum

1.65 wt%

3.8 wt%

Polycrysta-lline sample

2.3 times

Single Crystal

2.7 wt%

1.6 times

2.6 wt% @297 K 2.7 wt% @258 K

2.1 wt% @323K

DSC under high pressure

As hydrogen pressure was increased, an exothermic peak wasobserved; this trend is characteristic of hydrogen adsorption.

0 20 40 60-4

-2

0

2

0

2

4

6

Time (s)

Pre

ssure

(M

Pa)

Heat

flow

(m

W)

Hydro

gen P

ressure

(M

Pa)

Heat flow

(m

W)

(a)

(b)

A: H atoms.

Q: Is hydrogen adsorbed as H atoms or H2 molecules?

Mechanism

Grand Canonical Monte Carlo method

Q: Which structure of adsorbed hydrogen is energetically stable?

A: Organic linkers are preferential adsorption sites and the organic unit is a key to achieving good adsorption capacity.

(a)

H atom

P. Jena, J. Phys. Chem. Lett. 2, 206 (2011).

(a) Discussion

(a)Materials Carbon

system

MOFs Metal Hydrides Complex

Metal

Hydrides

Advantage reversible reversible reversible High H density

Disadvantage Too cold Too cold Too heavy and expensive irreversible

Physisorption Chemisorption Quasi-molecularbonding

H2 H H

■

We reported the synthesis and characterization of theC12H12CuN2O4 single crystal whose structure, operatingcapacity, and physical mechanism contrast with existing MOFs.

■

Conclusions

Structure・・・1D void space

Operating capacity・・・2.6 wt%, 3.8 wt%

■ Mechanism・・・Hydrogen is adsorbed as atoms.

T. Takami and K. Kawamura, APL Mater. 2, 096104 (2014). PCT/JP2015/63176

Problems

× Heavy weight, rare metal× Small adsorption amount at room temperature × Irreversibility of adsorption/desorption× Exothermic upon adsorption/desorption

Conclusions

× Heavy weight, rare metal

× Small adsorption amount at room temperature

× Irreversibility of adsorption/desorption

× Exothermic upon adsorption/desorption

⇒ ○ light element, element with the large Clarke number

⇒ ○ 2.3 times larger adsorption amount (World record among MOFs)

⇒ ○ reversibility due to a specific mechanism

⇒ ○ small exothermic (≪10 kJ/mol )

Conclusions

91%Down

70 MPa122 L100 kg

6.5 MPa88 L127 kg

6.5 MPa66 L95 kg

28%Down

Present Tank

3.8 wt%

▲FCV

Future(5.0 wt%)

Applications

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FIN.