Synthesis of metal hydrides employing vapor deposition technologies

Synthesis of metal hydrides Synthesis of metal hydrides employing vapor deposition employing vapor deposition

technologiestechnologies

Irmantas Barnackas, prof.L. PranevičiusLithuanian Energy Institute

2006 01 20

Outline of the presentationOutline of the presentation

• Hydrogen storage: metal hydrides (Mg2NiH4)

• Experimental work

• Conclusion

The main goal of the workThe main goal of the work

To investigate the possibilities of formation of Mg-based alloys (Mg2NiH4), used for hydrogen storage, employing physical vapor deposition method.

Hydrogen StorageHydrogen Storage Compressed gas storage tanks Carbon fibers and nanotubes Metal hydrides

Mg hydrides• light weight• low manufacture cost• high hydrogen-storage capacity

Limitations• Slow adsorption kinetics• High de-hydriding temperature (~573 K)• Stability of the MgH2

The kinetics can be improved by alloying with Ni → Mg2Ni (the capacity to approx. 3.6 % and TDes ~ 553 K

MaterialH-atoms per

cm3 (x 1022)

% of weight that is

hydrogen

MgH2 6.5 7.6

Mg2NiH4 5.9 3.6

FeTiH2 5.9 1.89

LaNi5H6 5.5 1.37

Hydrogen Storage: Mg-Ni-H systemHydrogen Storage: Mg-Ni-H system

The phases of hexagonal Mg2Ni alloy:• α (Mg2NiH0.3)• β (Mg2NiH4)

The Mg2NiH4 hydride has two crystallographic forms:• a low temperature (LT1 and LT2) modification• a high temperature (HT) modification

For T > 510 K, Mg2NiH4 has a cubic structure (HT phase) which becomes monoclinally distorted below this temperature (LT phase).

Experimental technique: Experimental technique:

• to produce nanocrystalline Mg, Ni and Mg2Ni thin film materials using magnetron sputtering;

• to hydrogenate MgNi thin films in hydrogen plasma and under high hydrogen pressure and temperature (p,T);

• to study MgNi thin films de-hydrogenation kinetics using GDOES techniques;

• to analyze MgNi thin films properties of as-deposited, after hydrogenation and de-hydrogenation using XRD, SEM and GDOES methods.

Experimental technique: Experimental technique:

The scheme of experimental device of MgNi thin films for deposition and hydrogenation

in hydrogen plasma

Parameters of as-deposited Parameters of as-deposited

Mg, Ni and MgNi filmsMg, Ni and MgNi films : :IMg = 1 A, UMg = 400 V

INi = 0.3 A, UNi = 450 V

UBIAS = -100 V, IBIAS = 10-20 mA

Deposition time - 5 min;

Substrate temperature – 330 K

Film thickness – 1 - 3μm

Working gas – argon gas

As-deposited Mg film: - XRD and SEM analysis

10 20 30 40 50 60 700

500

1000

1500

2000

2500

3000

3500

4000 IMg

= 1 A, UMg

= 400 V

UBIAS

= 100 V, IBIAS

=20 mA

t = 5 min.

Substrate - quartz

Substrate

h-Mg(103)

h-Mg(102)h-Mg(101)h-Mg(002)

As-deposited Mg film

Inte

nsi

ty, a

rb.u

Diffraction angle, 2 theta

XRD diffractogram of as-deposited Mg film on quartz substrate

SEM micrograph of as-deposited Mg film on quartz substrate

As-deposited Ni film: - XRD and SEM analysis

30 40 50 60 70 800

50

100

150

200

250

300

350

400 INi

= 0.3 A, UNi

= 440 V

UBIAS

= 100 V, IBIAS

=10 mA

t = 5 min.

Substrate - quartz

c-Ni(200)

c-Ni(111)

Inte

nsi

ty, a

rb.u

.


XRD diffractogram of as-deposited Ni film on quartz substrate

SEM micrograph of as-deposited Ni film on quartz substrate

As-deposited MgNi film: - XRD and SEM analysis

10 20 30 40 50 60 700

500

1000

1500

2000

2500

3000IMg

= 1 A, UMg

= 400 V

UBIAS

= 100 V, IBIAS

=20 mA

t = 5 min.

INi

= 0.3 A, UNi

= 440 V

h-Mg2Ni(006)

h-Mg2Ni(003)

Substrate - quartz

As deposited Mg2Ni

Mg2Ni standard

Inte

nsity

, arb

.u.


XRD diffractogram of as-deposited MgNi film on quartz substrate

SEM micrograph of as-deposited MgNi film on quartz substrate

Plasma hydrogenationPlasma hydrogenation

Parameters of hydrogenation:Pressure – 100 PaBias voltage – -300 ÷ -3000 V Ion current from plasma – 70-400 mATemperature of sample holder 40 °CHydrogenation duration – 30-120 min.

The schematic presentation of the plasma hydriding

MgMg22Ni thin film saturated with hydrogen atomsNi thin film saturated with hydrogen atoms

H irra d ia tio n+

S u bs trate

B o un d arie so f n a no g ra in s

C ha n ne lsb etw e e n co lu m ns

C om p re ss ives tre ss

- H yd rog e n atom s

C om p re ss ives tre ss

H sa tu ratedsu rfa ce

.. ... ... ... ... . - H sa tu rated su rfa ce

10 20 30 40 50 60 700

500

1000

1500

2000

2500

3000

c-Ni(111)

h-Mg2Ni(006)

h-Mg2Ni(003)

P(H2) = 100 Pa

t = 1 hourIBIAS

=40 mAU

BIAS= 300 v

After hydrogenation in hydrogen plasma

As deposited Mg2Ni

Inte

nsit

y, arb

.u.


MgMg22Ni films after Ni films after plasma plasma hydrogenation: hydrogenation: - XRD and SEM analysis

XRD diffractogram of Mg2Ni film after plasma hydrogenation using dc power supply

SEM micrograph of Mg2Ni film after plasma hydrogenation on quartz

substrate (DC power supply)

10 20 30 40 50 60 700

500

1000

1500

2000

2500

3000

c-Ni(111)

h-Mg2Ni(006)

h-Mg2Ni(003)

P(H2) = 100 Pa

t = 1 hourIBIAS

=150 mAU

BIAS= 900 v

After hydrogenation in hydrogen plasma

As deposited Mg2Ni

Inte

nsit

y, arb

.u.


XRD diffractogram of Mg2Ni film after plasma hydrogenation using dc power supply



substrate (DC power supply)

10 20 30 40 50 60 700

1000

2000

3000

4000

5000

h-Mg2NiH

0.3(006)

h-Mg2Ni(006)

h-Mg2Ni(003)

h-Mg2Ni(003)

h-Mg2Ni(006)

P = 100 PaU

BIAS= 3000 V

t = 1 hour

After plasma hydriding Mg

2Ni

As-deposited Mg2Ni

Inte

nsity

, arb

.u.


XRD diffractogram of Mg2Ni film after plasma hydrogenation using AC power supply



substrate (AC power supply)

10 20 30 40 50 60 700

1000

2000

3000

4000

5000

LT m-Mg2NiH

4(220)

LT m-Mg2NiH

4(110)

h-Mg2Ni(003)

h-Mg2Ni(006)

P = 100 PaU

BIAS= 3000 V

t = 2 hour

After plasma hydriding Mg

2Ni

As-deposited Mg2Ni

Inte

nsit

y, arb

.u.



XRD diffractogram of Mg2Ni film after plasma hydrogenation using AC power supply


substrate (AC power supply)

Reactive sputtering inReactive sputtering in Ar+H Ar+H2 2 plasmaplasma

10 20 30 40 50 60 700

500

1000

1500

2000

2500

3000 UMg

= 160 V

UNi

= 320 V

Substrate - quartz

Mg2NiH

4 standard

Mg2Ni standard

c-Ni(111)

IMg

= 1 A,

INi

= 0.3 A,

t = 30 min.

P = Ar+H2

Ni standard

Inte

nsi

ty, a

rb.u

.


XRD diffractogram of MgNi film after reactive sputtering on quartz

substrate

SEM micrograph of MgNi film after reactive sputteringon quartz substrate

Hydrogenation of MgNi thin films in high hydrogenHydrogenation of MgNi thin films in high hydrogenpressure and temperature (p,T)pressure and temperature (p,T)

The schematic view of the hydrogenation cell for the studies of the adsorption properties

Parameters of hydrogenation: Pressure – 8 barTemperature – RT – 523 KHydrogenation duration – 30-120 min.

10 20 30 40 50 60 700

2000

4000

6000T = 523 K

Hydrogenation properties: P(H2) = 8 bar

After hydrogenation for 120 min.



As-deposited Mg

2Ni

Mg2NiH

4 standard

Mg2Ni standard

Inte

nsit

y, arb

.u.


MgMg22Ni films after hydrogenation in high hydrogen pressure and Ni films after hydrogenation in high hydrogen pressure and

temperature (p,T) : temperature (p,T) : - XRD analysis


temperature (p,T) : temperature (p,T) : - SEM analysis

a

b

SEM micrograph of MgNi film after hydrogenation in high hydrogen pressure and temperature (p,T) on quartz substrate:

a – after 30 min.; b – after 60 min.


temperature (p,T) : temperature (p,T) : - SEM analysis

SEM micrograph of MgNi film at different magnification after hydrogenation in high hydrogen pressure and temperature (p,T) on quartz substrate

Studies of deStudies of de--hydrhydrogenationogenation kinetics of Mg kinetics of Mg22NiHNiH44 thin films thin films

The schematic view of the de-hydrogenation cell for the studies of the desorption properties

XRD analysis of XRD analysis of Mg2NiH4 film after de-hydrogenation process

DeDe--hydrhydrogenationogenation kinetics of Mg kinetics of Mg22NiHNiH44 thin films: SEM and XRD thin films: SEM and XRD

SEM analysis of SEM analysis of Mg2NiH4 film after de-hydrogenation process

10 20 30 40 50 60 700

1000

2000

3000

4000

5000

Hydrogenation (p,T): T = 523 K t = 60 min.De-hydrogenation: T = 770 K t = 30 min.

After de-hydrogenation for 30 min.


h-Mg2Ni(200)

h-Mg2Ni(203)

c-Mg2NiH

4(311)

c-Mg2NiH

4(220)

c-Mg2NiH

4(111)

As-deposited Mg

2Ni

h-Mg2Ni(006)

h-Mg2Ni(003)

Inte

nsi

ty, a

rb.u

.


GDOES analysis of desorption of Mg2NiH4 thin film

Studies of deStudies of de--hydrhydrogenationogenation kinetics of Mg kinetics of Mg22NiHNiH44 thin films thin films

Basic parameters:

T = 770 K, t = 30 min.

ConclusionsConclusions1. 1-3 µm Mg, Ni and Mg2Ni thin films were successfully deposited on the quartz

substrates using magnetron sputtering.

2.2. Observed formation of amorphous phase during plasma hydrogenation using DC Observed formation of amorphous phase during plasma hydrogenation using DC power supply. It can be related to formation of the compressive stresses and power supply. It can be related to formation of the compressive stresses and defragmentation of the material. defragmentation of the material.

3.3. Formation of low temperature (LT) m-MgFormation of low temperature (LT) m-Mg22NiHNiH4 4 thin films after hydrogenation of thin films after hydrogenation of

MgMg22Ni in hydrogen plasma for 2 hours using AC power supplier is observed.Ni in hydrogen plasma for 2 hours using AC power supplier is observed.

4. After the hydrogenation of Mg2Ni thin films in hydrogen atmosphere, in high pressure and high temperature, Mg2NiH4 thin films were successfully formed.

5. SEM results show formation of “bubbles” on the surface during hydrogenation in (p,T). It can be related to the high temperature during hydrogenation and formation of the compressive stresses. These bubbles were lifted after de-hydrogenation and some parts of thin films were destroyed.

Synthesis of metal hydrides employing vapor deposition technologies

Documents

Transcript of Synthesis of metal hydrides employing vapor deposition technologies