Benefit and safety aspects of nanotechnology

-From the viewpoint of carbon nanotubes for a low-carbon society-

M. Endo

Shinshu University

Japan

OECD Conference on

Potential Environmental Benefits of

Nanotechnology:Fostering Safe Innovation-Led Growth

Conventional technology has contributed to building our fertile but

environmentally unfriendly civilization.

From now on, high-tech such as emerging nanotechnology will

contribute to realize the sustainable world.

And we have to start RIGHT NOW

Contents1. Nanotechnology and Carbon Nanotubes (CNT)

2. Manufacturing and green fuel production by CNT Process

3. CNT applications to lithium-ion battery (LIB) and LIB-based

electric vehicle for ultra low emission

4. Lead-acid battery using CNT and its contribution to the

Environment

5. CNT composite materials and its environmental effect

6. CNT composite rubber and oil development and water saving

7. The role of impurities to the safety issue of CNT

8.Conclusions; Green and safe innovation led by CNT for the

future of our planet

Layered Materials (1959)

What could we do with layered structures with just the right layers? What would the properties of materials be if we could really arrange the atoms the way we want them. They would be interesting to investigate theoretically. I cant see exactly what would happen, but I can hardly doubt that when we have some control of the arrangement of things on a small scale, we will get an enormously greater range of possible properties that substances can have, and of different things that we can do.

R. P. Feynman

There is Plenty of Room at the

Bottom

December 29, 1959

1. Nanotechnology and Carbon Nanotubes (CNT)

Diamond

Graphite

CNT

5nm

Single walled

carbon

nanotube

Carbon nanotube

Millionth of a millimeter thick carbon cylinder

DWCNT

Multi-walled Carbon nanotubes

2m

PAN-based Carbon Fiber

1nm

Carbon Nanotube

M.Endo

Space Elevator

The goals of the NNI are to:

Maintain a world-class research and development program aimed at realizing the full potential of nanotechnology;

Facilitate transfer of new technologies into products for economic growth, jobs, and other public benefit;

Develop educational resources, a skilled workforce, and the supporting infrastructure and tools to advance nanotechnology; and,

Support responsible development of nanotechnology

Now, CNT research is shifting from well-established basic science to

also application technology !

Source: http://www.nano.gov/html/about/home_about.html

Safety for success !

Catalytic CVD Method

Industrially applied for mass-production

Possibility and potentiality for controllability of

MW- ,DW- and SW-NT structure

2, Manufacturing and Green Fuel by CNT process

5nm

4.039nm0.377nm

3.208nm

Single, double and multi-walled

CNTs by CCVD process using

iron particle as catalyst

Fe catalytic particle

A. Oberlin, M. Endo,

and T. Koyama,

Journal of

Crystal Growth

32, 335-349 (1976)

A. Oberlin, M. Endo,

and T. Koyama,

Journal of

Crystal Growth

32, 335-349 (1976)

The first one is responsible

for the formation of the

inner core containing long,

straight and parallel carbon

lavers cylindrically rolled

around a hollow tube.

A. Oberlin, M. Endo,

and T. Koyama,

Journal of

Crystal Growth

32, 335-349 (1976)

Exposed SWNT during

the growth of crossing the

tubes

A. Oberlin, M. Endo,

and T. Koyama,

Journal of

Crystal Growth

32, 335-349 (1976)

Double layered carbon nanotube

in the core of the VGCF

A. Oberlin, M. Endo,

and T. Koyama,

Journal of

Crystal Growth

32, 335-349 (1976)

A. Oberlin, M. Endo,

and T. Koyama,

Journal of

Crystal Growth

32, 335-349 (1976)

A. Oberlin, M. Endo,

and T. Koyama,

Journal of

Crystal Growth

32, 335-349 (1976)

2 n m2 n m

CNT grown from an Iron catalyst particle

M. Endo

American Chemical

Society,

CHEMTECH,

September, 568-576,

(1988).

M. Endo,American Chemical Society, CHEMTECH, September, pp.568-576, (1988).

100 300 5000

20

40

60

80

100

Diameter of Fe particle ()

Rela

tive y

ield

(%

)

M. Endo American Chemical Society,

CHEMTECH, September, pp.568-576, (1988).Fluidization seeding permits better

control of the catalyst-feed ratio

and the product aspect ratio.

Fluidization- produced VGCF has a

crystallographic structure similar

to that of substrate-produced

VGCF, but with much smaller

hollow tubes of 2-3 nm (Figure 9).

The TEM image shows the catalyst

particle at the end of the growing

precursor fiber; it is not yet covered

with hard, graphite-like carbon

layers and can still actively assist

fiber growth in the longitudinal

direction. The resultant thin fibers

have a continuous, thin, hollow tube

as shown in Figure 11b.

M. Endo

American Chemical

Society,

CHEMTECH,

September, pp.568-

576, (1988).

Growth model of CNT by floating catalyst

MWCNT(VGCF) mass production

system and commercialization started

since 1988

hydrocarbon

(benzene) +

catalytic particles

gas outlet

H2

CNT

hydrogen

gas outlet

M.Endo, Japanese Pat.

, , Vol.24, No.5, pp.227-237, (1986).

M. Endo, American Chemical Society,

CHEMTEC, 568-576, (1988).

First stage of early 15 years, the productivity had increased by 1015 times

Mass produced CCVD multi -walled CNT (Dia. 40nm)

1

CNT manufacturing process itself is toward the hydrogen economy as a carbon

fixation and hydrogen production system, when it becomes enough large

Top cover

Safety vent

Gasket

PTC

Insulator

Anode can

Insulator

Cathode Anode

Separator

Anode lead (Cu)

Cathode lead (Al)

Structure of LIB practical cellCommercialization started since 1991 by SONY

Ref :

Sonys catalog, Lithium ion rechargeable battery, ACG-4012-N-9707-P3-002, 1977.

M. Endo, T. Karaki, T. Fujino New ceramics 1988; 4: 46-52, (In Japanese)

M. Endo, T. Hayashi, Y. A. Kim, H. Muramatsu, Development and application of carbon nanotubes, Jap. J. Appl. Phys., 45, 4883-4892 (2006).

3. CNT applications to lithium-ion battery (LIB) and LIB-based Electric Vehicle

for ultra low emission

Toyotas plug-in car

model

Principle of operation of Li-ion-Battery

LiCoO2Graphite

Li

O

Co

Endo lab.

Graphite sheet LiC18 LiC6

5m

Cu foil

MWCNT

M. Endo, Y. A. Kim, T. Hayashi, K. Nishimura, T. Matsushita, K. Miyashita

and M. S. Dresselhaus, Carbon, Vol.39, pp1287-1297, (2001).

70

100

95

85

90

80

0 10 20 30 605040

Cyclic umber

Rel

ati

ve c

harg

e i

n d

isch

arg

e c

ap

aci

ty

%

0% 1% 10%5%VGCF

Artificial graphite (HTT2500)with VGCF

Cyclic characteristics of synthetic graphite anode

as a function of weight percent of CNF(MWCT)

M. Endo et al., Carbon, 39, 1287-1297 (2001).

Schematic model to absorb

the stress by NT for Li-ions

intercalation to graphite

host

7.15

6.625.83

4.51

2.39 Power/Heating

Industry

Deforestation

Transport

Household

Total

7.15

6.62

5.83

2.391.80

26.5 Billion Tons

IPCC Fourth Assessment Report, WGlll, 2007. World Business Council for Sustainable Development, 2004

EDMC / Directory of Energy and Economic Statistics 2007

Overview of Global CO2 Emissions

in 2004

[109 t]

Plug-in HV

[109 t]

10% Decrease)Reference

Ministry of Land, Infrastructure, Transport and Tourism, Japan

If cars all over the world become Plug-in Hybrid Vehicle...

23.8 Billion Tons

(-3Bt=

By M.Endo

Key tech,

LIB

(HEV, EV, FCEV Plug-in car)

MWCNT can contribute to the21st centurys

environment, energy and information technology by LIB !

Coming soon the age of full electric car

The Automotive Battery The Motorcycle Battery (Sealed type)

Cover (Polypropylene)

Container (Polypropylene)

Anode: lead grid filled with spongy

lead

Separator (Polyethylene)

Anode (Pb)

Cathode: lead grid filled with PbO2

Cover (PP or ABS)

Container(PP or ABS)

H2SO4 electrolyte

Separator (Glass fiber or Synthetic fiber)

H2SO4 electrolyte

cathode

anode

Pb+PbO2+2H2SO4 2PbSO4+2H2O

Construction of Lead-Acid Batteries~Since 1860, performance improvement was only 50% ~

4. Lead-acid Battery using CNT and its contribution

to the Environment

RoHS directive since 2003 led to the reduction of Pb consumption

except rechargeable lead acid battery for motor vehicles (Japan)

Lead consumption

Lead production

World market for production and consumption of Lead

Illegal disposal of the lead-acid battery will happen frequently by the rising

motorization in the world, and which should be protected for global environment.

10Tt/Y

Larger part of Pb consumption is for the

lead-acid batteries such as for cars and

electric bicycles.

Model of Electronic Conductive Network in Active

Material with CNT ( from Yuasa Journal)

Advanced

Lead-Acid

Battery

Annual usage of PbO in Japan is 300 thousand tons

0 200 400 600 800 1000

40

60

80

100

Change in the Cell Capacity During the

Charge-Discharge Cycling Test ( at 25)

(by S. Hojyo from Yuasa Journal)

Cycling charge and discharge regime

Discharge:0.67A to 1.70V/cell

Charge:7.35V (max1.5A) -6H

Cycles

Dis

cha

rge

cap

aci

ty (

%)

Addition of MWCNT to

negative plate

No CNT

aditive

Superior battery life

Built-in type

car battery,

Optical network unit

M. Endo et al., Vapor-grown carbon fibers (VGCFs) Basic properties and battery application,

Carbon, Vol.39, pp1287-1297, (2001).

ConverterInverter

Lead Acid Battery

Engine

Advanced Lead Acid Battery by Incorporating

MWCNT for Diesel Engine-based Hybrid Bus

0.1mm

0.2mm

Precise plastic composite based on nanotubes

High tribological properties

Superior transcribing properties injection molding

The gear(a) made by MWNT composite material

by injection molding

5.CNT Composite Materials and its Environmental Effect

CNT/ plastic composite is useful for

windmill of wind-power generation

composite

Collaboration; Nissin Industry and M.Endo

Much lighter weight and strong as steel !

Carbon Nanofiber composite material project NEDO&Ministry of Economy)

(3) Structures and properties of CNT/Al systems

CNT/Al/N/O interfacial

surface phaseAl matrix phase

Huge cells Baskets

Cage cellulation

Cellulation in Al/CNT composite

ightness

Ant

corrosionThermal

expansion

FC250Al AC2B

m

0

500

50

01000

0

0

10

0

600

150

0

CompositesCast-iron

m

0

500

50

01000

0

0

10

0

600

150

0

Properties of the composites

Strength(MPa)

Thermal

resistance

Thermal conductivity W/mKW/mK

Comparison of the strength

Mg/CNT (Si coated) composite as light as

engineering plastics

Si coated

CNT/Aluminum

306 kg

Aluminum

138 kg

Plastics

117 kg

Gum

66 kg

Glass

34 kg

Others

53 kg

CNT/Magnesium197 kg

Aluminum

138 kg

Plastics

117 kg

Gum66 kg

Glass

34 kg

Others

53 kgSteel

892 kg

Aluminum

138 kg

Plastics

117 kg

Gum

66 kg

Glass

34 kg

Others

53 kg

Material Ratio for Automobiles*1

CNT/Aluminum

CNT/Magnesium

CNT/Aluminum

CNT/MagnesiumTotal

1300 kg

Total

714 kg

Total

605 kg

45.1%

53.5%

Al and Mg/CNT composites can provide light weight and

high safety flamebody

*1 TOYOTA Technical Review,

Vol.53, 219(2004)

million tons

60 million tons

Decrease of CO2 Emission (Calculated with CO2 Emission - Weight Relation*1)

-60 million tons

-72 million tons

50.0%

60.0%

CNT/Aluminum

CNT/Magnesium

Steel

CNT/Aluminum

CNT/Magnesium

(*1 Ministry of Land, Infrastructure, Transport and Tourism Japan)

(*2 JAMA, Japan Automobile Manufacturers Association )

of CO2/year

of CO2/year

of CO2/year

120

of CO2/year

48 million tonsof CO2/yearcar

Run: 10,000 km/year

Production: 60 million cars/year*2

0.2% decrease

0.3% decrease

CNT Rubber Composite for Oil Development and Water Saving

O-ring(a)

Init

ial R

eser

vo

ir P

ress

ure

(M

Pa

)

Reservoir Temperature ()

0

Present Work

Mary AnnMarnock

Eugene Island

North Ossum

(117, 62MPa)

Mobile Bay

South Texas(222, 91MPa)

Walter O&G

Mobile Bay 862(215, 129MPa)

Current

Technology

(b)

Figure S1. (a) Downhaul devices in underground resources probing using rubber seals as a key

component and (b) the distribution of temperature and pressure of the current oil wells, for example.

Note that our developed innovative technique will allow us to excavate oil from unreachable deposits

found deeper and at higher temperatures (as high as 260 C at 239 MPa). The authors would like to

thank Dr. T. Baird for his permission to use his original figure in High-Pressure, high-temperature well

logging, perforating and testing, Schlumberger Oilfield Review, 50-67 (1998)

M.Endo et al., Advanced Functional Mater.,18,3403(2008)

(Source: British

Petroleum World

Energy Statistics)

(Source: Calculated based on Life Cycle

Inventory Analysis of Fossil Energies in

Japan /

The Institute of Energy Economics, Japan

(1999) Gross Heating Value Base

Comparison of Greenhouse Gas Discharge (CO2 equivalent )

from Fossil Fuel by LCA

Electric powewr generation from natural resources in various countries

Immersion time (hours)

0200 400 600 800 1000

50

100

150

200

Res

idu

al c

hlo

rine

con

centr

atio

n (

ppm

)

Comp-3

Current

0

250

Figure Variations of the chlorine concentrations of chlorine solutions containing the carbon black

(Current) - and multi-walled carbon nanotubes (Comp-3) -incorporated rubber composites as a function of

immersion time. The chlorine solution containing current sample become opaque whereas there is no

changes in the solution containing Comp-4 sample (see Insets).

(Valve; opening-closing)Endurance test

Comp-3; 300,000 times

Current; 50,000 times

Multi-walled Carbon Nanotube-filled Rubber Nanocomposites for

Environmentally Durable Valve Sealant to Prevent Water Leakage

The rubber composite

has five times longer

durability.

Present rubber

composite is very

useful for Water warks

to prevent the water

leak for 5 times longer

than current rubber.

World Wide 400 million t/year CO2 Redaction

Present rubber can contribute to the CO2 -1.5% reduction per year and save the

clean water in world wide scale

Safety for Success !Pathological reactions on CNT in mice andexpected bio/medical applications

M. Endo and S. Koyama (Shinshu University, Japan)Collaboration with NIOSH Dr. V.Castranova

Methods

Animals: Mice

Materials: CNT vs Asbestos

Implantation: Subcutaneous tissue

Period: 6 months

Histology: H-E stain

Active oxygen species ,scavenged by agent as iron, are considered to inactivate

enzymes in the cells, damage DNA and destroy lipid membrane which should

cause every disease, aging as well as cancer as far as the most recent medical

research is concerned. In this experiment, the iron content is controlled as low as

200 ppm or less.

abdominal cavity of mice

Subcutaneous

implantation

Aspiration

&

inhalation

Testicles

Causing mesothelioma , if inhaled, and if they migrate to the edge of the

lungs ?

7.The role of Impurities to the safety of CNT and mouse plumonary responce

x40

x400

SWCNT(HIPCU)

4 weeks after subcutaneous implantation

1.Thicker granulomatous tissue

2. Suggesting more active inflammatory

response of SWCNT than MWCNT

S. Koyama & M. Endo, Carbon 44, 1079-

1092, 2006

Are there differences of biological responses depending on the property of Carbon

nanotubes?

To be publishedS.Koyama, M.Endo et al; In vivo immunological toxicity in mice of carbon

nanotubes with impurity, Carbon 47 (2009)1365

Proinflammatory (TNF, IL-6) cytokines

1.5

6.5

11.5

16.5

21.5

26.5

31.5

36.5

41.5

46.5

0 day 2 weeks 4 weeks 8 weeks

pg

/ml

TNF

Control

MWCNT-low

Purification

MWCNT-high

Purification

1.5

6.5

11.5

16.5

21.5

26.5

31.5

36.5

41.5

46.5

51.5

0 day 2 weeks 4 weeks 8 weeks

pg/m

l

I L -6

Control

MWCNT-low Purification

MWCNT-high Purification

Tumor necrosis factor alpha (TNF, cachexin or cachectin) is an important cytokine involved in systemic inflammation and the acute phase response.

IL-6: secreted by macrophages, induces acute phase reaction. Interleukin-6 (IL-6) is a pro-

inflammatory cytokine secreted by T cells and macrophages to stimulate immune response to trauma, especially burns or other tissue damage leading to inflammation.

Th1 (IL-12, IFN) cytokines

IFN

1.5

201.5

401.5

601.5

801.5

1001.5

1201.5

1401.5

1601.5

0 day 2 weeks 4 weeks 8 weeks

pg

/ml

Control

MWCNT-low

Purification

MWCNT-high

Purification

IL-12

1.5

6.5

11.5

16.5

21.5

26.5

31.5

36.5

0 day 2 weeks 4 weeks 8 weeks

pg

/ml

Control

MWCNT-low

Purification

MWCNT-high

Purification

IL-12: NK cell stimulation, Th1 cells induction.

Interleukin 12

(IL-12) is an

interleukin

that is

naturally

produced by

macrophages

and human B-

lymphoblastoi

d cells (NC-

37)in response

to antigenic

stimulation.

Interferon-is secreted by T-cells and natural killer lymphocytes.

All classes of

interferon

production.

Th2 (IL-4, IL-10) cytokines

IL-10

1.5

21.5

41.5

61.5

81.5

101.5

121.5

141.5

0 day 2 weeks 4 weeks 8 weeks

pg

/ml

Control

MWCNT-low

Purification

MWCNT-high

Purification

IL-4

1.5

6.5

11.5

16.5

21.5

26.5

31.5

36.5

0 day 2 weeks 4 weeks 8 weeks

pg

/ml

Control

MWCNT-low

Purification

MWCNT-high

Purification

IL-4: involved in

proliferation of B cells, and the

development of T cells and mast cells. Important role in

allergic responses.

IL-4 is a cytokine

that stimulates the

proliferation of

activated B-cells, T-

cells, and

differentiation of

CD4+ T-cells into

Th2 cells, among

other effects. It is a

key regulator in

humoral and

adaptive immunity.

IL-10: inhibits Th1 cytokine production.

Interleukin-10 (IL-10), also known as human cytokine synthesis inhibitory factor

(CSIF), is an anti-inflammatory cytokine, capable of inhibiting synthesis of pro-

inflammatory cytokines like Interferon-gamma, IL-2, IL-3, TNF and GM-CSF by

cells such as macrophages and the Type 2 T helper cells.

Summary

Carbon nanotubes should be purified to make it

free of several kinds of contaminations that are

formed during production processes.

It should be also better to develop the increased

biocompatibility of carbon nanotubes.

Viability Studies of Pure Carbon- and

Nitrogen-Doped Nanotubes with

Entamoeba histolytica : From

Amoebicidal to Biocompatible

StructuresAna Laura Elas, Julio Csar Carrero-Snchez,Humberto Terrones, Morinobu Endo, JuanPedro Laclette, and Mauricio Terrones ;

Nanoletter

Viability Studies of Pure Carbon- and Nitrogen-Doped Nanotubes with Entamoeba

histolytica : From Amoebicidal to Biocompatible StructuresAna Laura Elas, Julio Csar Carrero-Snchez,Humberto Terrones, Morinobu Endo, JuanPedro Laclette, and Mauricio Terrones ; Nanoletter

The discussion of what makes nanotubes

safe or harmful has to be based on science,

and has to be handled carefully.

TGA curves of non-mixed and NaCl-mixed MWCNT-20 (a) and

MWCNT-80 (b) for various mixing ratios of MWCNTs:NaCl

Res

idual

quan

tity

(%

)

Temperature ()

200 400 600 8000

20

40

60

80

100

0w/w%

NaCl

0.5w/w%

NaCl0.1w/w%

NaCl1w/w%

NaCl

0w/w% NaCl

(as-grown)

(a) MWCNT-20 (HTT:2600) (b) MWCNT-80 (HTT: 2800)

Temperature ()

200 400 600 8000

0w/w%

NaCl0.5w/w%

NaCl

0.1w/w%

NaCl

1w/w%

NaCl

Res

idual

quan

tity

(%

)

0w/w% NaCl

(as-grown)20

40

60

80

100

M. Endo et al., Sodium Chloride-Catalyzed Oxidation of Multi-Walled Carbon

Nanotubes for Environmental Benefit; J. Phys. Chem. B 110(24), 12017 (2006).

Responsible production ;For environmental issue in the CNT mass production era

Functions and Applications of Carbon Nanotubes

EMI

Bio-Sensor

Bio/Medical

Electric Conductivity

Hybrid Vehicle

Sensing

IT

Advanced Composites

Energy

Strength

Secondary

Battery

CapacitorFuel Cell

Thermal Device

Display Device

Bio compatibility

Catalyst

Physiology

Absorption

Adsorption

Morphology Mechanics

Electronic Engineering

Thermology

Thermal Conduction

Field EmissionEnergy Exchanger

MEMS

Semiconductor

Heat Exchanger

Modulus

Electric Vehicle

HE Device

Chemical Engineering

FUNCTIONS

APPLICATIONS

Environment

X-ray/ion source

8.Conclusions; Green and Safe Innovation led by CNT for the Future of our Planet

Conclusions1. Nanotechnology as safe and innovative technology is changing

our way of life.

2. Nanotechnology will solve the currently faced environmental andenergy problems

3. The viability of carbon nanotubes strengthens with itscommercialization after a detailed clarification of theirenvironmental and health safety issue

4. We have proceeded beyond the first mountain of science, thesecond mountain of technology and the third mountain ofeconomy by successful large-scale production of carbonnanotubes at a reasonable cost with the concept of responsibleproduction and uses.

5. Now we are striving to climb the mountain of society. By sharingthe all information on risks and benefits of the materials with allstakeholders, we will finally reach the top of a nanotubemountain and prove the carbon nanotubes to be the safeinnovative materials in the 21st century.

Society

Science

Technology

Economy

Carbon nanotube, as a leading-edge

of nanotech, must go beyond the four

mountains for realization of safe and green

innovation in the 21st century.

Worldwide collaboration on science and

technology including safety issue is the

key for big success by getting social

agreement.