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Graphene Materials For Clean Energy Applications

Hui-Ming Cheng (成会明)

Advanced Carbon Division

Shenyang National Laboratory for Materials Science

Institute of Metal Research, Chinese Academy of Sciences

72 Wenhua Road, Shenyang 110016, China 中国科学院金属

研究所 沈阳材料科学国家（联合）实验室先进炭材料研究部

E-mail: cheng@imr.ac.cn

World’s Energy Needs up to 2050

14 TW (2010) to 28 TW (2050)

D. Larcher & J. M. Tarascon, Nature Chem., DOI: 10.1038/NCHEM.2085, 17 Nov. 2014

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World Energy Production

R. E. Smalley. 27th Illinois Junior Science & Humanities Symposium, Apr. 3(2005)

Stationary and Mobile Electric Energy Storage

Large scale electricity storage Electricity storage for EVs & MDs

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Characteristics of ESDs

Y Gogotsi, et al, Nat. Mater. 7:45 2008

High energy density

High power density

Strategies for Improvement of Energy Storage Materials

• Core-shell structuring

• Composite and

hybridization

• Surface modification

• Configuration design

Liu C, HMC*, Advanced materials for energy storage (Review), Adv. Mater., 22(2010) E28.*

• NanostructuringHigher energy density

• Nano/micro combination

Higher power density

Higher reliability

Longer life

Lower cost

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Active substance

Conducting network

Interface controller

Substrate for composites

Key materials for EES: Carbon

CB

Porous C

Graphite

Graphene

CNT

Coating

Advantages of graphene materials for energy applications

Toller MD, et al NanoLett. 8(2008)3498

Li D, et al , Nat Nanotech. 3(2008)101

Geim AK, et al., Nature Mater. 6(2007) 83

High electric conductivity

Flexible and transparent

Rich porous structures

Easy surface functionalization Facile fabrication of membranes,

coatings and 3D structures

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• Use of graphene in lithium ion batteries and

supercapacitors

Structure of LIBs

Tarascon JM et al, Nature, 414: 359 (2001)

a) Cylindrical, b) Coin, c) Prismatic, d) Thin and flat

Main modules:

• Current collectors

• Electrolyte

• Separator

• Cathode• Active mater.

• Binder;

• Conducting additive

• Anode• Active mater.

• Binder;

• Conducting additive

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Graphene Materials for LIBs

• Coating on current collectors

• Conductive additive

• Components for hybrid electrode

materials

Good Cycliability@ high rateHigh Rate Capability

Shi Y, Cheng HM, et al., J. Power Source 196(2011)8610

94.8%

Graphene-Li4Ti5O12 (4.8wt%)

Li4Ti5O12

2. Graphene Materials as Conducting Additive for LIBs

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GS by Chemical ReductionNature Graphite

GS by Arc Discharge

GS byThermal Reduction

3. Graphene materials as anode materials？

Many defects

…

• High irreversible capacity• Low first Coulumbic efficiency

High irreversible

capacity:

High surface area

Rich functional

groups

4. Making Hybrids: Use Graphene as Electrode Materials for ESDs

Sy

e

• Suppression of agglomeration, restacking,

and volume change

• Formation and uniform dispersion of NPs

• Highly conductive and flexible network

• Large capacity/capacitance

• Enhanced cycling stability

• Good rate capability

Oxides GO, rGO or GS Hybrids

nergistic

ffect

• Agglomeration• Poor conductivity• Big volume change

• High capacity• High density

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Structure of graphene Hybrids

(a) Anchoring, (b) Wrapping, (c) Encapsulation,

(d) Sandwich, (e) Layering, (f) Mixing

Wu ZS, Cheng HM, et al., Nano Energy (invited review), 1(2012)107.

Wet Chemistry Synthesis of Graphene Hybrids

ZS Wu, et al., Nano Energy (invited review) 1, 2012, 107-131.

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715800

631484

Improvement of rate performance

Wu ZS, Cheng HM, et al. ACS Nano, 4(2010)3187.

767High capacity + improved cyclability

Anode for High Energy LIBs-- Co3O4/rGO Hybrids (Anchoring)

Electrode for High-Energy ECs-RuO2/rGO Symmetric ECs

Synergistic Effect

Better cyclic performance Higher energy at high power

ZS Wu, HMC*, et al., Adv. Funct. Mater. 20, 3595 (2010).

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• Macroscopic mechanism (ex situ)

– Formation of well-dispersed uniform oxide nanoparticles on graphene

– Suppression of pulverization of oxide particles

– Formation of a conductive network

– Prevention of re-stacking of rGO

• Microscopic mechanism (in situ)

– Increase of Li+ diffusion rate to improve Li+ reaction kinetics

– Restriction of volume expansion

Shan XL, Li F, Cheng HM, et al. J Mater Chem A, 2014.

Au Tip STM Tip

Model material

Graphenehybrid

LithiumLi2O

-2V bias

e-

Role 1 of Graphene Materials: Formation of Well-Dispersed Uniform Nanoparticles

Fe3O4/CDGCo3O4/CDG

Fe3O4Co3O4

Without rGO:

- serious agglomeration

- large size

With rGO:

- nanometer size

- homogeneous dispersion

• Large electrode/electrolyte

contact area

• Short path for Li+ transport

• Good stability

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Role 2 of Graphene Materials: Formation of Conductive Networks

• high electrical conductivity, rapid charge-transfer

process, good Li+ kinetics for uptake and extraction

Role 3 of Graphene Materials: Suppression of Pulverization of Oxide Particles

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Role of Nanoparticles: Prevention of

Re-stacking of rGO

• Beneficial for electrolyte access and Li+ transport

CDG

CDGcomposites

Model MaterialsNiO@graphene hybrids (hydrothermal)

Strong interaction

NiO/graphene mixture (grinding) Weak interaction

NiO NSs

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No

Many

Few

Many

Few

No

G M Zhou, F Li, HMC, et al, ACS Nano 2012

“Oxygen Bridge” mechanism

Oxygen bridge bonding at strong interacted interface: C-O-Ni

C-O-Ni

Oxygen Bridges between Oxides and rGO

Zhou GM, Cheng HM, et al. ACS Nano, 6(2012)3214.

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Calculation of oxygen bridge bonding

Bonding strength: 10 times higher

G M Zhou, et al, ACS Nano 2012

In Situ Studies on the Role of GrapheneMaterials

Au Tip STM Tip

Model material

Graphene hybrid Lithium

Li2O

-2V bias

e-

A nanocell in a TEM chamber

Shan XL, Li F, Cheng HM, et al. J Mater Chem A, 2, 17808 – 17814 （2014）.

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Role 1: Increasing Li+ Diffusion Rate/ Improving Li+ Reaction Kinetics

Li+ diffusion rate

0.0

0 1 2 3 4 5 6 7 8 9 10 11 12

CountsShan XL, Li F, Cheng HM, et al. J Mater Chem A, 2, 17808 – 17814 （2014）.

2.0x101

4.0x101

1.4x102

1.2x102

1.0x102

8.0x101

6.0x101

1.6x102

1.8x102

Diff

usio

nR

ate

(nm

/s)

NiO@grapheneNiO/graphene NiO NSs

137 nm/s

23 nm/s

4 nm/s

NiO@graphene

a b

NiO/graphene

e

50nm

Top-view

side-view

c d

50nm

Top-view

side-view

f g h

Role 2: Interfacial Expansion-Restriction Effect

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• Increase of the Li+

diffusion rate

• Improvement of the

Li+ reaction kinetics

• Interfacial expansion

restriction

High power den

sity

g

Superior cyclin

performance

Excellent Lithium

storage

Graphene’s Role in LIBs

Shan XL, Li F, Cheng HM, et al. J Mater Chem A, 2, 17808 – 17814 （2014）.

• Use of graphene materials in Li-S batteries

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Development of Li-ion batteries

18 650 cylindrical-type

Jeong, G, et al, Energy Environ. Sci., 4, 1986 (2011)

Importance of Li-S batteries

P. Bruce, et al, Nature Mater， 2011

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Li-S batteries

• Advantages High capacity

2567 Wh/kg@S Vs 420 Wh/kg@L

Cheap, rich, Environment friendly

• Problems Fast capacity fading

Poor cyclibility

• Reasons• Insulating

• Shuttle effect of polysulfides

• Volume change during charge/discharge

IB

Sulfur

nanocrystals

anchored on

graphene

Zhou GM, Cheng HM, et al. ACS Nano, 7(2013) 5367

1. Graphene-anchored Sulfur

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10 20 30 40 50 60 70

Cycle number80 90 100

1200

1100

1000

900

800

700

600

500

400

300

200

100

0

0.75 A g-1C

apac

ity(

mA

hg

-1)

100

90

80

70

60

50

40

30

20

10

0

Co

ulo

mb

icE

ffic

ien

cy(%

)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Cycle number

0

200

400

600

800

1000

1200

1400

1600

0.75 Ag-1

4.5 Ag-1

3 Ag-1

1.5 Ag-1

0.75 Ag-1

0.3 Ag-1

Cap

acit

y(m

Ah

g-1

)

0 200 400 600 800 1000 12001.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

Capacity(mAhg-1)

Vo

ltag

e(V

vs.L

i+/L

i)

1.6 1.8 2.0 2.2 2.4 2.6

Potential(Volts)vs Li+/Li2.8

-2

-1

0

1

21st cycle 2nd cycle 3rd cycle 4th cycle

Cu

rre

nt

de

ns

ity(

A/g

)

G-S63 hybrid

1st charge/discharge

G-S63 hybrid

G-S63 hybrid

ba

d

c G-S63 hybrid

Graphene-anchored Sulfur

2. Graphene Membranes and Buffer Layers

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Design of a sandwich structure

Improve adhesion

Lower internal impendence &

polarization;

Adsorb and trap polysulfides

Increase surface area

• Polysulphides are blocked in cathode and re-used during cycling.

Zhou GM, Li, F, Cheng HM, et al, Adv Mater, 26(2014)625, inside cover

Improvement of wetting ability

Graphene coating beneficial to the wetting and preserving of electrolyte

Strong adhesion between sulfur slurry and graphene

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Graphene current collecotr

Polymer separator (up) and graphene-coated polymer

separator (bottom)

Electrochemical performance

Function of GCC & G-separator

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Be an internal current

collector

Improve adhesion

Lower internal impendence

and polarization;

Adsorb and trap

polysulfides

Excellent flexibility and

high strength

3. Internal graphene current collector and buffer layer

G@separator

S-G@separator

Zhou GM, Li, F, Cheng HM, et al, Adv Mater, 2015,doi:10.1002/adma.201404210 (inside front cover).

Structure of S-G@separator membrane

C F

S

SO

a bGraphene

PP Separator

c

ed f

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Superior performance

Zhou GM, et al, Adv Mater, 2015, doi:10.1002/adma.2 01404210.

4. Improvement of areal capacity

“Double Low” Issues

• Low sulfur loading

– typically <2 mg cm-2

• Low sulfur content

– typically <70 wt%

• Low areal capacity

• Low energy density

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Synthesis of graphene foam (GF)

Chen ZP, Cheng HM , et al., Nature Mater 10 (2011) 424

Free-Standing Graphene Foam

• Ultra-low density: ~5 mg/cm3, very light aerogel

• A very high porosity: ~99.7%

• Specific surface area: ~900 m2/g

170×240mm2

Z Chen, W Ren , HM Cheng, et al., Nature Mater 10 (2011) 424

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Graphene Foam-rGO

3D Nested Hierarchical Network

• GF-rGO: high porosity and specific surface area; 3D networks

• GF: highly conductive network

• rGO: anchoring sulfur nanoparticles via functional groups

GF-rGO 3D Nested Hierarchical Networks

• GF-rGO: high porosity and specific surface area; 3D networks

• GF: highly conductive network

• rGO: anchoring sulfur nanoparticles via functional groups

GF

rGO aerogel

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GF-rGO/S Cathode for Li-S Batteries

GF

GFrGO

S

100μm

rGO

100μm

100μm 100μm

• Sulfur loading: 14.4 mg cm−2; Sulfur content: 89.4 wt%

o1 2 3 4

c

s

KeV

Electrical Performance of GF-rGO/S Cathode

a b

c d

• Low polarization; Good cycling stability

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Areal Capacity Comparison

• High sulfur loading and high sulfur content

• High areal capacity, good rate capability and cycling stability

C Xu, W Ren, et al, Adv. Mater., accepted, 2015.

• Use of graphene in flexible energy storage

devices

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Heavy & Thick & Stiff Light & Thin & Flexible

Jeong G, et al, Energy Environ. Sci., 4(2011)1986

Trend of mobile devices & power sources

Nokia Humanform

Samsung

Power for Flexible Devices

Stiff & bulky

Light, thin & flexible

• Integratible with

electronic devices

• High capacity per area &

mass

• Superior mechanical

flexibility

• Vital component:

Free-standing flexible

electrodes

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Carbon materials for flexible ESDs

GM Zhou, HM Cheng, et al, Energy Environ. Sci., 7(2014)1307

Anodic Electropolymerization (AEP)

C)

G-PANi: Graphene/Polyaniline Composite

Graphene

G-PANi

Graphene

1. Graphene/PANi paper for flexible supercapacitors

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Capacitance & stability performance

• High gravimetric & volumetric capacitance;

• Excellent cyclic stability.

DW Wang, HMC*, et al., ACS Nano 3:1745 (2009)

2. Graphene/cellulose paper for flexible supercapacitors

Advantages of Cellulose Paper:

Low cost

Superior mechanical flexibility

3D porous texture

Good wettability

Cellulose paper

Cellulose fibers

Y Cui, et al, PNAS 106, 21490 (2009)

Paper

Coating CNTs on Paper

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Only 6% increase of R

(curvature radius of ~4 mm)

cellulose paper GCP

Graphene/cellulose paper for flexible supercapacitors

Microstructures of GCP

Filter paper GCP

Surface

Cross section

GNSs

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Performance of GCP Electrodes

Good rate ability Superior cyclic stability

Gravimetric capacitance: 120 F g-1 (based on the mass of Graphene)

Areal capacitance: 81 mF cm-2

Performance of GCP Flexible ECs

Outstanding flexibility

GCP can be tailored to

various shapes to meet

various applications in

thin electronic devices.

Z. Wen, HMC*, et al, Adv Energy Mater, 1: 917(2011)

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• Sufficiently light• Flexible and integrated• Highly conductive

• Binder-free• Conducting additive-free• Metal current collector-free

2. Graphene-based flexible LIBs

e―Cathode

Separator

Anode

e―Li N, Cheng HM, et al, PNAS 109 (2012)17360.

Chen ZP, Cheng HM , et al., Nature Mater 10 (2011) 424

Washing

Calcinati

on

Anode: GF/Li Ti 0 (LTO)

Synthesis of electrode materials on GF

Precursor solution for active materials

• No conducting additive

• No binder

• Good contact and strong binding between active

materials and graphene current collectors

4 5 12

Cathode: GF/LiFePO4 (LFP)

Graphene

Hydrothermal

Li N, Cheng HM et al, PNAS, 109(2012)17360.

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Performance of GF-based Flexible LIB

No metal current collector;

No binder; No additive!

Li N, Cheng HM et al, PNAS, 109(2012)17360.

Voltage: 1.9 V

Capacity (Cell):

137 mAh/g (0.2C)

High rate performance! Fully charged in 6 minutes.

0.0

0.5

1.0

1.5

1202.0

2.5

3.0

Pot

entia

l(V

vs.

Li+

/Li)

0.2C1C5C

0.5C2C10C

1-2.5 V

60

80

100

140

Cap

acity

(m

Ah/

g)

10C

a b

Performance of GF-based Flexible LIB

Li N, Cheng HM et al, PNAS, 109(2012)17360.

0 20 40 60 80 100 120 140 0 20 40 60 80 100Capacity (mAh/g) Cycle number

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4. GF-based electrodes with high sulfur loading

Zhou GM, Li, F, Cheng HM, et al, Nano Energy, 2015 (11), 356-365.

Electrochemical performance of the S-/PDMS/GF electrode

1.5 A g−1

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• Supercapacitors– PANi/G

– RuO2/G

– MnO2/G

– G-cellulose paper

ACS Nano 2009Adv Funct Mater 2010

ACS Nano 2010

Adv Energy Mater 2011

• LIBs– LiFePO4/G

– Li4Ti5O12/G

– TiO2/G

– B/N-doped G

– LiF-modified G

– Co3O4/G

– Fe3O4/G

PNAS 2012J Power Sources 2011

Adv Funct Mater, 2011

ACS Nano, 2011

Adv Fucnt Mater, 2012

ACS Nano, 2010; J Power Sources, 2014

Chem Mater 2010; Carbon 2014

• Li-S batteries– Fibrous G/S

– G/S/G

– G/S

– GF/S

– GF-rGO/S

ACS Nano, 2013

Adv Mater, 2014

Adv Mater, 2015;Nano Energy 2015;

Submitted

Graphene-based composites for ESDs

High power density

High energy density

High rate capability

• Use of graphene in OLED devices

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Ambient Pressure CVD for Graphene Growth on Cu

Gao, Ren, Cheng, et al., Appl Phys Lett 97 (2010) 183109.

7 inch

Nondestructive H2 Bubbling Transfer method

2 H2O (l) + 2 e- H2 (g) + 2 OH- (aq)

• No damage on metal substrate

• Highly efficient, no pollutions

• Easy to scale up

• Suitable for transferring graphene grown on any metals

Gao, Ren, Cheng, et al., Nature Commun 3 (2012) 699.

Patents: ZL 201110154465.9, PCT/CN2012/076622

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R2R Bubbling Transfer of Graphene

Unpublished result

Continuous R2R Bubbling Transfer of Graphene

• 300-500 / for monolayer without doping Unpublished result

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4 inch Flexible OLED with Graphene Anode

Unpublished result

In collaboration with Prof. Dongge Ma @ CIAC, CASUnpublished result

Summary and Prospect

• Role of graphene materials in various energy storage devices:

– Highly conductive network

– Improved ion diffusion

– Control of volume change

– Effective buffer layer

– Good flexibility

Significant progress in mass production of

graphene materials

Vigorous explorations of graphene-based

materials for clean energy devices

On-going commercialization of graphene-based

energy devices

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Acknowledgment

• Dr. Feng Li• Dr. Rencai Ren

• Dr. Jinhong Du• Dr. Songfeng Pei• Dr. Lei Wen• Mr. Kun Huang• Ms. Ying Shi

• Prof. Quanhong Yang at Tianjin Univ.• Dr. Dawei Wang @ UNSW, AU

• Dr. Zhong-Shuai Wu

• Dr. Guangmin Zhou

• Dr. Na Li

• Dr. Zongping Chen

• Mrs. Lu Li

• Mr. Xuyi Shan

• Mr. Chuan Xu

Acknowledgement

•

•

•

• Deyang Jinghua New Carbon Co.

• Deyang Carbonene Tech. Co.

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Editor-in-Chief: Hui-Ming Cheng

Publisher: Elsevier

Website: http://www.journals.elsevier.

com/energy-storage-materials/

High-quality papers are welcome!

Submission NOW: http://www.evise.com/evise/faces/pages/navigation/NavC ontroller.jspx?JRNL_ACR=E

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