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2006 DOE Hydrogen Program Review

Electron-Charged Graphite-Based Hydrogen Storage Material

Chinbay Q. Fan

Gas Technology Institute

May 18, 2006

STP 13This presentation does not contain any proprietary or confidential information

Overview

> Project start: July 1, 2005

> Project end: June 30, 2009

> Percent complete: 15%

Cost: use inexpensive graphiteWeight and volume: use high density graphite, maximizing capacityEfficiency: add electron charge to increase storage rateDurability: use electron charge to control cyclesRefueling Time: use electron charge to increase fueling rateCodes and StandardsSystem Life-Cycle Assessments

> Total project funding– DOE share: $1,562K– Contractor share: $390K

> Funding received in FY05: $110K

> Funding for FY06: $150K

Timeline

Budget

Barriers

Superior Graphite Co.

Chicago, Illinois

Partners

ObjectivesOverall Development of a hydrogen storage device for

hydrogen quick charge and discharge, high wt% and vol% storage capacity, durability over many cycles, and safe handling and transport.

2006 • Select materials and conduct graphite-processing steps • Test and evaluation cycles for hydrogen storage • Construct an electron charge device and evaluate the concept with the modified graphite materials.

2007 • Prepare samples for independent evaluation • Investigate performance optimization and prototype container systems.

Plan and ApproachTask 1. Proof of

Feasibility1. Select materials for

intercalation2. Test and evaluate

hydrogen storage cycles3. Theoretical calculation

Task 2. hydrogen Storage Optimization

1. Prepare samples for independent evaluation

2. Performance optimization3. Investigate process steps

Task 3.Prototype Development and Process Scale Up

1. Pilot evaluation of production steps

2. Production cost and market potential

Task 4. production and Market Assessments

1. Build prototype systems

2. Analysis of market

60%

Com

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e N

ot st

arte

d

Not

star

ted

Not

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ted

Technical Accomplishments/ Progress/Results

Achieved 4.5Å space between graphite flakes. This 4.5Å can allow hydrogen molecules to enter.Intercalated different metals to change the graphite electronic configuration: Mg, Li, Al, and Ti etc.Achieved 1% hydrogen storage with graphite based materials in early-stage tests.Built an electron-charge device for hydrogen storage and observed the effect of external charges on the hydrogen storage.

Accomplishments/Progress/ Results

Hydrogen Storage Material DevelopmentGraphite expansion and oxidationSEM and TEM analysis of the expansionExpanded graphite reduction and mechano-chemical intercalationStructure reorganization under heat treatmentHydrogen uptake and release using high temperature, high pressure TGA as well as Sievert devices

Graphite Samples for Hydrogen Storage Materials

Flake graphite for platesGTI 4926Batch 73703

Flake graphite for platesGTI 2926 RGAPHSO-4-40-02

Unique SGCoGTI SR11993SO-4-40-06

Boron graphiteGTI 9039 RGSO-4-40-01

Fullerine graphiteGTI FullerineSO-4-40-04

Flat flakesGTI 2935 GRAPHSO-4-40-03

Purified carbon black with graphiteGTI SCD310SO-4-40-07

High bulk density, sphericalGTI SLA 1518SO-4-40-09

High bulk density, sphericalGTI SLC 1520SO-4-40-08

Worm structureGTI Compacted WormsSO-4-40-05

NotesSample NameSuperior Batch

Flake graphite for platesGTI 4926Batch 73703

Flake graphite for platesGTI 2926 RGAPHSO-4-40-02

Unique SGCoGTI SR11993SO-4-40-06

Boron graphiteGTI 9039 RGSO-4-40-01

Fullerine graphiteGTI FullerineSO-4-40-04

Flat flakesGTI 2935 GRAPHSO-4-40-03

Purified carbon black with graphiteGTI SCD310SO-4-40-07

High bulk density, sphericalGTI SLA 1518SO-4-40-09

High bulk density, sphericalGTI SLC 1520SO-4-40-08

Worm structureGTI Compacted WormsSO-4-40-05

NotesSample NameSuperior Batch

AccomplishmentsDifferent Graphite Shapes Fabricated and Tested

Graphite shape modification, metal intercalation, and coating for hydrogen storage

AccomplishmentsGraphite Expansion

2939APH (D50~10um; BET surface area: 9 m2/g)

Step 1air-milling

Thermally Purified natural crystalline flake graphite G2900G8

Accomplishments

Aggressive intercalation + oxidation

Step 2

AccomplishmentsEnlarged SEM showing high surface area

BET surface area: 700 m2/gThe space between graphite layers is

more than 4.5Å

TGA of the Expanded Graphite for Hydrogen Storage

SO#4-49-18

99.8

99.85

99.9

99.95

100

100.05

0 1000 2000 3000Time (sec.)

Wgt

(%)

0

50

100

150

200

250

Tem

p (°

C)

Graphite SO#4-49-18 Temp

TGA Used for Fast Screening for Hydrogen Storage and Cycle Lifetime

High temperature, high pressure thermo gravimetric analysis (TGA) is used to test the hydrogen storage and cycle lifetime.Look for the storage capacity decay under different pressures.Screen material modification to increase the hydrogen storage capacity and decrease hydrogen charge/discharge decay rate.

Hydrogen Uptake/Release Cycle on Graphite-based Material

Hydrogen storage capacity increases while the hydrogen release decreases.

1200

1200.5

1201

1201.5

1202

1202.5

1203

1203.5

4000 9000 14000 19000 24000 29000 34000 39000 44000 49000 54000

Time (sec.)

Wei

ght (

mg)

0

20

40

60

80

100

120

Tem

pera

ture

(o C)

Weight Temperature (C)

Hydrogen Storage Capacity Decays with Cycles under Different Pressures

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 2 4 6 8 10 12Cycles

Hyd

roge

n St

orag

e C

hang

e (w

/w%

)

H2 Storage at ambient pressure H2 Storage at 136 KPa H2 Storage at 340 KPa

y = -0.0053x + 0.1225

y = -0.0053x + 0.0733

y = -0.0044x + 0.0434

Sievert Method to Test Hydrogen Storage Capacities

Measure the hydrogen storage and release capacity at steady state under different temperatures.Calculate the enthalpy (∆H) of the hydrogen adsorption

vent

PT0-2000psi

VConVectorr

vacuum gaugeReferencevolume

isolating valve

VV

turbo pump

backing pump

Cold cathodevacuum gauge

sample bomb

isolating valve

isolating valve

isolating valve

vent valve

isolating valveisolating valve

filter

filter

pressure regulator

pressure regulator

H2 cylinder

He cylinder

SenTorr pressure gaugecontroller

process meter

Seivert's Apparatus

isolation valve

PT0-300psi

filter

Turbo-V70 controller

Pressure/Composition Isotherm Curves of the Graphite-based Hydrogen Storage

MaterialStorage capacity: 0.8 ~ 1.0 wt%

10

100

1000

10000

0 0.002 0.004 0.006 0.008

H.C. (mole/gram)

Pres

sure

(KPa

)100°C des70°C des40°C des20°C ads0°C ads-20°C ads

Heat (∆H) of the Metal Modified Graphite Material Derived from PCT Curves

y = -2.7304x + 22.892R2 = 0.9962

10

11

12

13

14

15

16

2.5 3.0 3.5 4.0 4.51/T*1000 (K-1)

lnP

(Pa)

∆H = -22.7 kJ/mol

The heat release (∆H) of the metal modified graphite material for hydrogen adsorption is –22.7 kJ/mol. The theoretical calculation of pure metal alloy for hydrogen adsorption is approximately –33 kJ/mol. The metal modified graphite has low heat produced in the hydrogen adsorption.

Electron-charged Device for Hydrogen Storage

Electron-charge Effect on Hydrogen Storage

1.0E-03

1.0E-02

1.0E-01

1.0E+00

1.0E+01

0.0000 0.0010 0.0020 0.0030 0.0040 0.0050 0.0060H.C. (mole/gram)

Pres

sure

(MPa

)

0V -5V +5V

Room Temp.

Electron-Charge Effect on Hydrogen Storage

The PCT shift is related to the electronic structure of the substrate. Electron-rich material needs positive charges and electron-poor material needs negative charges. External charge shifts the chemi-sorption to physi-sorption and shifts physi-sorption to chemi-sorption with different charges.Exploring benefits in conventional metal hydride and newer materials

Future Work

Test and evaluation cycle for hydrogen storage1. Modify testing apparatus2. Test the expanded and intercalated graphite

materials3. Investigate the electron charge effect on

different hydrogen storage substrates.Calculate and compare the theoretical charge sufficient for the hydrogen storage target

Future Work

Prepare samples for independent evaluationInvestigate performance optimization and prototype container systemInvestigate process steps for productionPreliminary analysis of production costsPilot-evaluation of key production stepsPrepare samples and prototype containers for independent evaluation

Summary

> Demonstrated the hydrogen storage capacity 0.8~1.0 Wt% of graphite-based materials.

> Achieved 4.5Å space between graphite flakes

> Demonstrated the external electron charges affect the hydrogen storage. The PCT curves of the graphite-based materials show that the positive charges reduce the hydrogen storage and negative charges increase the hydrogen storage

Acknowledgements

> Financial Support from DOE: DE-FG36-05GO15010.

> DOE Supervisors: Jesse J. Adams, Carole J. Read, Sunita Satyapal

> Dr. Hideaki Itoh, The Japan Steel Works, Ltd.

> Dr. Jun Shu and Frank P. Vultaggio, INCO Special Products.

> Prof. Deyang Qu, university of Massachusetts.