2012/11/13

Charge-Discharge Curves of Various Carbon Materials
素子材料特論第３授業
1.8

Li-ion電池負極（II）
ハードカーボン系負極

Potential (V) vs. Li/Li+1.5
1.2
Graphitizable carbon

0.9
Non-graphitizable carbon

0.6Graphite

0.3
0.0
0200

400

600

800

1000-1

Capacity (mAh g )Figure 1-4. Charge-discharge profiles of representative carbon materials

Anodic performance and their related factors
Performances

Factors

Capacity• Sites for Li incorporation

Potential for charge• Reversibility of charge and discharge• Over potential• Non-electrochemical reaction

and dischargeMechanisms for Lithium Insertion in Carbonaceous Materials

charge and discharge rate

• Diffusivity of Li

Non-dischargeable charge• Reactivity of electrolyte• Reactivity of anode, hetero atomic groups,
terminal C-H, edge carbon• Irreversible sites for Li incorporation

Cycle ability• Irreversible charge in structure

Safety• Stability of charged Li• Li-Carbon intercalation• Thermal stability of SEI• Reactivity of electrolyte

Figure 1-5. (a) Plot of reversible capacity for Li vs. HTT for a variety of carbon samples (□hard carbon, ■ soft carbon), (b) Charge capacity as a function of the height of stacking(Lc002)J. R. Dahn,* Tao Zheng, Yinghu Liu, J. S. Xue SCIENCE, 270, 27 OCTOBER 1995

12012/11/13

Characteristics of various materials
Precursor

Graphite(over 2800oC)

Graphitizablecarbon(600~800oC)

Nongraphitizablecarbon(1000~1400oC)

Advantages

Disadvantages

Natural graphite
Artificial graphite
MCMB
Needle cokes
VGCF

Low dischargepotential(around 0.2V)
Long cycle life

Low discharge capacity(372 mAh/g)
High cost

MCMB
Meso phase pitch
Green cokes

High capacity(700~1000mAh/g)
Low cost

High discharge potential(around 1.0V)
High irreversible capacity
Poor cycle stability

Thermosetting polymer
Glassy carbon
Coal
Organic material
Stabilized isotropic pitch

High capacity(400~700mAh/g)
Low dischargepotential(around 0.1V)
Low cost

High irreversible capacity
Fig. 3. Reversible capacity of region 1 carbons plotted as a function of the probability P of turbostratic disorder
between adjacent carbon sheets. The line is the relation 0 = 372(1 - P), where Q is the capacity. For the purposes ofthis plot, samples corresponding to different symbols are equivalent.

ハードカーボンハードカーボンのカーボンの製造
原料：難黒鉛化性前駆体- Biomass: Husk, Cellulose, Sugar, Rignin, Tree, Crab（Chichin), …
- Polymer: Phenol Resin, Unsaturated Resin, Epoxy Resin- Pitch:Isotropic Pitch and Coke
• 熱処理温度- ８００～１４００℃• 構造- 難黒鉛化性カーボン•

Fig. 2. Plots of voltage versus reversible capacity for the second charge-discharge cycle of representative carbon
samples from regions 1, 2, and 3 of Fig. 1. (A) Synthetic graphite (Johnson-Matthey); (B) petroleum pitch (Crowley TarCo.) heated to 5500C; (C) resole resin (Occidental Chemical Co.) heated to 1 0000C. Arrows designate the directions
the curves are traversed as Li is added to (to the right) or removed from (to the left) the carbon samples.

2

2012/11/13

ガラス炭素の微細構造

ハードカーボンハードカーボンの構造
カーボンの構造
２次元的構造３次元的構造11

ハードカーボンの長所と短所

活性炭素繊維の微細構造
In order to remove oxygen containing functional groups for removing the heterogeneous effect of STM,
OG7A and OG20A were heat-treated at 800OC in a hydrogen atmosphere ( H2 / He =1/4).

OG20A-800H

OG7A-800H

Channelingpore(Inter-particles)
Slit shaped pore(Intra-particle)

Slit shaped pore(Intra-particle)

5nm

25nm

5nm

25nm

♣Vacant spaces between the two domains of OG20A are larger than that of OG7A.
♣Domain size of OG20A is a little smaller than that of OG7A.
♣Slit type pores were observed in domains of OG7A and OG20A.

長所- 高容量が可能- 安価（?）- 資源が豊富（?）- High rate property- Hybrid系材料が可能- 低温特性がよい。
- 電解液のPC使用可能
• 短所
- 低密度
- 放電プロフィルがNon-platten- 不純物の除去が困難- 低１st cycle Coulombic efficiency- 低Cycle性- …
•♣It can be presumed that almost pores larger than 2nm nucleated by the inter-particle
mechanism.
1032012/11/13

Hard Carbon from Indonesian Mangrove Char
Elemental analysis & Surface area

STM image of IM1000

Elemental analysis (wt%)

S.A.
(m2/g)

C

H

NO

AshIM

70.6

3.6

0.38

23.7

1.7

-IM 700

89.4

1.0

0.72

582

3.1318

IM 800

90.0

0.8

0.74

5.5

3.019

IM 900

91.0

0.6

1.17

4.3

3.0

3

IM 1000

91.5

0.5

1.13

4.0

2.9

541000

XRD
IM700
IM800
IM900
IM1000Intensity

800

600

400

200

01020304050

2 theta14

Microstructure of carbon derived from mangrove charcoal and its application in Li-ion batteries, Liu, Tao; Luo, Ruiying; Qiao,Wenming; Seong-Ho Yoon, et al., ELECTROCHIMICA ACTA, 55, 1696-1700, 2010

“Li+ storage sites in non-graphitizable carbons prepared from methylnaphthalene-derived isotropic pitches(MNIP)”, Carbon, 38, 995 1001 (2000), C. W. Park, S. I. Lee, S.H. Yoon, S. M. Oh4

2012/11/13

Hard Carbon from Indonesian Mangrove Char

Li-NMR of Various Carbons
MAG(CCCV charge to 0V)

Ch-Dis Profile-100-50

050100-100-50050100

Potential (V) vs. Li/Li+2.0150200
IMV1000(CCCVcharge 250to 0V)

150200250

1.5

1.00.5

IMV2400(CCCV charge to 0V)

Ar 1000
Vac 1000abundance

0.00-100-50050100

150200

100

250

200

300

400

500

600

Capacity (mAh/g)

IMA1000(CCCV charge to 0V)
Condition-100-50050

100

150

200

250

IMA700(CCCV charge to 0V)-100-50050

100

150

200

Ch
(mAh/g)Dis(mAh/g)

Efficiency(1cy, %)

Cap.irrev.
(mAh/g)Ar 1000

62846974.7159

Vac 1000

50345390.１50IM

250ppmIM V1000 showed the better initial efficiency than that of IM Ar1000
19

理想的なハード理想的なハードカーボンなハードカーボン

ハードカーボンの充放電機構•••••••••••

Low-crystallized carbon materials for lithium-ion secondary batteries,
Hayato Higuchi, Keiichiro Uenae, Akira Kawakami
JOURNAL OF POWER SOURCES, 68, 1997

高密度： 1.9g/cm3以上
高容量： 650mAh/cc
高レート性： 90%以上（５C/0.2C: Half cell, ２０C/0.2C:Single cell）
Low Impurity: 100ppm以下
安価： 800円/Kg以下
高1st Coumbic efficiency
高低温特性
高サイクル性
豊富な原料からの調製
マイルドな炭化条件
Hybrid系が可能な材料：SnOxまたはSiとのハイブリッド化⇒高容量化⇒ 達成するためには、各々因子に対応する原因把握が要求。
⇒ まだ、原因解明が明らかになっていない。
⇒ 今後の研究に期待する。
今後の研究に期待する52012/11/13

Fig. 2. Galvanostatic charge–discharge profiles for micro-Si (10 μm) anode.

Figure 1-15. Typical high performance materials as anode ;(a) Comparison of graphite, Si, Sn and Sb(b) Volume expansion model of Si during charge

J.H. Ryu, J.W. Kim, Y.-E. Sung, S.M. Oh
Electrochem. Solid State Lett., 7 (2004), p.
A306

High performance material & their problems
 SiO, Si and Sn (SiO 2100, Si 4200, Sn 931 mAh/g) are very promisingmaterials as anodic materials of LIB for their large theoretical capacities,
however, they have poor cycle performances because of internal crack inparticles caused by large volumetric expansion in charge process.
Li-Si systemRef.) J. Power Sources 192 (2) (2009) 644-651

CompoundStructure

Unit cell vol.
(A3)

Vol. / Si atom
(A3)

Si

Cubic

160.2

20.0

Li12Si7

Orthorhombic

243.6

58.0

Li14Si6

Rhombohedral

308.9

51.5

Li13Si4

Orthorhombic

538.4

67.3

Li22Si5

Cubic

659.2

82.4

Volumeexpansion(over 400%)

Cycling behavior of SiOx with different oxygen content and particle size

Ref. : A. John Appleby and et al., J Power Sources 163 (2007) 1003-1039

22J. Yang, Y. Takeda, N. Imanishi, C. Capiglia, J.Y. Xie, O. Yamamoto
Solid State Ionics, 152–153 (2002), p. 125

62012/11/13

Specific capacity vs. cycle number for nano-crystalline Si and nano-amorphous Si thin film
anodes prepared by thermal vapor deposition. Specific capacity of graphite and bulksilicon anodes also shown
J. Graetz, C.C. Ahn, R. Yazami, B. Fultz
Electrochem. Solid-State Lett., 6 (2003), p. A194

Cycling performance of carbon-coated silicon anodes in 1 M LiPF6 EC:DMC (1:2) at different
water contents present in the electrolyte. In all cases, the ‘exhaustion point’ (last extractionpeak) is centered around 1000 mA h/g
Electrochimica Acta
Volume 48, Issue 11, 15 May 2003, Pages 1579–1587

Relative intensity(a)(b)
(c)

108

106

104

102

100

98

Binding energy (eV)SEM morphology of 250 nm a-Si film on Cu cycled at C/2.5 for (a) 1 cycle, and (b) 30
cyclesJ.P. Maranchi, A.F. Hepp, A.G. Evans, N.T. Nuhfer, P.N. Kumta
J. Electrochem. Soc., 153 (2006), p. A1246

Figure Schematic model of cocoon shaped composite of silicon monoxide and surficialcarbon nanofiber (SiO-CNF composite)

7

2012/11/13(a)Potential (V) vs. Li/Li+

1.8

1cycle2cycle3cycle

1.5
1.2
0.9
0.6
0.3
0.0
0300(b)

1.8
Potential (V) vs. Li/Li+

600
900
1200
Capacity (mAh/g)

1500

1cycle2cycle3cycle1.5
1.2

Figure 2-12. SEM images of electrode surface after 3 cycles : (a) SiO-CNF composite with Fe catalyst, mixtureof SiO-KB (b) or SiO-CNF (c).

0.90.6
0.30.00300

600
900
1200
Capacity (mAh/g)

1500

Figure Cycle performances with SiO-CNF composite until 3 cycles according to the various amount of CNFs
with Ni (a) or Fe catalyst (b).

Comparison bet. Composite and Mixture

769825826

450

Coulombic efficiency

st300

100

65.8

61.9

38.1

50

52.00Composite Composite（Ｎｉ） （Fe cat.））（Ｎｉ cat.）

Mixture(CNF)

Mixture(KB)

Volume expansion

Composite （Ni cat.））68%

Mixture (CNF)

32%

300

Mixture (KB)

14%15251.2
0.90.61cycle2cycle3cycle

0.005

1020

1.5

1.2
0.9
0.6

1cycle2cycle3cycle0.30.00Cycle

250

500

750

1000

1250

1500

1750

2000

200
153%
126%

0.90.61cycle2cycle3cycle

0.3

250

500

750

1000

1250

1500

1750

2000

0

Capacity (mAh/g)

250

500

750

1000

1250

1500

1750

2000

Capacity (mAh/g)

Si-CNF model

Problems of Si-CNF composite

efficiency at 1st cycle

248%

1.2

0.00

Capacity (mAh/g)

 Small particle size, under 1um, is reasonable

301%

300

Efficiency : 75%

0.4umSi-CNF

1.81.50.30

Efficiency : 71.9%

1umSi-CNF(88%)

1.81.5 High discharge capacity and coulombic

Electrolyte penetration only (2days)
After charging to 0V

124%

Efficiency : 70.0%

5umSi-CNF(87%)

1.8

600

Superiority of the CNF composite

400

112%

Si-CNF composite : CNF growth directly on Si(5um, 1um, 0.4um)
+

-1

88%

Potential(V) vs. Li/Li

Discharge capacity

600

Composite （Fe cat.）
）

+

1180

900+

1253

150

Potential(V) vs. Li/Li

1335

1479

Discharge capacity (mAh g )900Volume expansion (%)-1Capacity (mAh g )1200

Charge capacity

Coumombic efficiency at 1 cycle

1500

Retention
rate

Cycle performance

Potential(V) vs. Li/Li

At 1st cycle

Problem in Si-CNF composite

 Excellent cycle performance Lower volume expansion

 Poor initial efficiency because of high surface area by CNF growth⇒ CNF growth provides spaces to relieve volume

 Binding force bet. Si and CNF are needed

Exfoliation

 Although CNF growth on Si particle of 0.4um (Si-CNF composite), Si-CNF composite didn’t

expansion and conductivities to improve performances

100show improved cycle performance because CNF exfoliated from Si which had no surface acidity.
Composite (Fe cat.)

Mixture (CNF)

Mixture (KB)

30328

2012/11/13

Oxidized Si-CNF composite

Preparation of PCSi-CNF composite

To improve surface acidity,
Si particle was oxidized at 700~900℃℃ for 3 hrs with H2Og.
Schematic modelPC/ or CNF amount (wt. %)CodePerformance test

Oxide film

PC

CNF

PC recoating

1263

OxidizedSiSiCondition

Step I

Si-PC

6%--

PC coating(900℃℃-CH4/He- 30min)

Step II

Si-PC-CNF

6%

93 %-

CNF growth on PCSi
(580℃℃-CO/He- 30min)

Step III

Si-PC-CNF-RC

6%

93 %

-Catalyst removal by HCl

Step IV

Si-PC-CNF-RC-PC

6%

93 %

8%

PC re-coating(900℃℃-CH4/He- 30min)-98 %-CNF growth directlyon Si surface

Discharge capacity(mAh/g)

CNF

Initial efficiency (%)

442

56.7

336
24.3

8%

As
PreparedUniformity ↑Adhesion ↑Samples

327
21.7

16%

23.0

30%

Extent of oxidation
Comparison

Si-CNF

Adhesive power and uniformity of CNF was improved by surface
oxidized Si, where as charge-discharge performance became poor.
3335

Composite of PC coated Si and CNF

Analysis of PCSi-CNF composite
SEM & TEM

As a solution, Pyrolytic carbon (PC) coating on Si particle is suggested.

XRDIntensity (cps) Step I : PC is coated on Si particle to improve adhesion between Si and CNF (PCSi).

C(002)⇒ The coated PC provide conductivity with Si particles as well as adhesion strength.
 Step II : CNF is grown on PCSi to improve cycle performance

2530

40

N2-BET300
2

PC re-coating

Si-1

Si-PC (8 m g )2 -1
Si-PC-CNF (105 m g )2 -1
Si-PC-CNF-RC (107 m g )2 -1
Si-PC-CNF-RC-PC (68 m g )3Carbon Nanofiber(CNF)

35
2 Theta-1Ref.) Carbon 47 (15) (2009) p.3338-3391
Step III
Step IV

Adsorption amount of N2 /cm (STP) g

Fe catalyst
PC coating

Si-PC-CNF-RC-PC

Si-PC-CNF-RC
Si-PC-CNF

decreasing surface area.
Step II

Si-PC

Si-PC-CNF-RC-PC

Si-PC
No PCSi Step IV : PC is re-coated on PCSi-CNF composite to improve initial efficiency by

Step I

Si-PC-CNF-RC-PC

Fe Step III : Removal catalyst by HCl treatment

No PCSi

Si-PC200PCCNF

PC 再コーティング

100Si
0
0.0

0.2

0.4

0.6

0.8

1.0

Relative pressure, P/P0343692012/11/13

Cycle performances of PCSi-CNF composite

Discharge capacity (mAh g-1)

Potential(V) vs. Li/Li+

Effi.：75%

1.5

Si

1.2

Exfoliation

0.9
0.6

1cycle2cycle3cycle

0.3
0.0
0500

1000
1500
-1
Capacity (mAh g )+Potential(V) vs. Li/Li

Step II

1500

1000

PC被覆なしCNF-Si複合体
Step II
Step III
Step IV

500

2000

PCSi-CNF
1.8Carbon, 47, 2009, 2049–2053, G. Wang et al.

Cycle performance

Si-CNF composite1.8

Graphene nanosheets for enhanced lithium storage in lithium ion batteries

0510Cycle (times)

PCSi -CNF (Fe removal)
Step III

Effi.：76%

1520

PCSi -CNF (PC re-coating)
Step IV

Effi.：76%

Effi.：79%

1.5
1.2
0.9
0.6

1cycle2cycle3cycle0.3

1cycle2cycle3cycle1cycle2cycle3cycle

0.0
0400

800
1200
Capacity (mAh/g)

1600

0

400

800
1200-1
Capacity (mAh g )

0

1600

4008001200-1
Capacity (mAh g )The decreased surface area

1600

37

Cycle performances of PCSi-CNF composite
Capacity at 1st cycle (mAh/g)

SamplesComparison

SamplesComparison

効率(%)
効率

ChDis

Si-PC-CNF

1709

1299

76.0

Si-PC-CNF-RC

1674

1272

76.0

Si-PC-CNF-RC-PC

1415

1115

78.8

Si-CNF

2037

1535

75.4

At 20 cycle (mAh/ g)Dis.(max)(mAh /g)Dis

Retention rate (%)

Si-PC-CNF

1317

1051

80

Si-PC-CNF-RC

1318

903

69

Si-PC-CNF-RC-PC

1136

873

77

Si-CNF

1535

670

44Charge and discharge curves of graphene nanosheets as anode in lithium-ion cells. The
inset is the cyclic voltammograms of graphene nanosheet electrode38102012/11/13Single wall carbon nanotube paper as anode for lithium-ion battery
Electrochimica Acta
Volume 51, Issue 1, 5 October 2005, Pages 23–28

Preparation and electrochemical properties of Ag-modified TiO2
nanotube anode material for lithium–ion battery
Electrochemistry Communications
Volume 9, Issue 3, March 2007, Pages 425–430

Hybridization of Si/PyC/CNF and NG

20Si/PyC/CNF and NG

50Si/PyC/CNF and NG
1000

900

Discharge capacity (mAh/g)

Discharge capacity (mAh/g)

1000

800
700
600
500
400
300

20Si/PyC/CNF:NG = 5:520Si/PyC/CNF:NG = 3:720Si/PyC/CNF:NG = 2:820Si/PyC/CNF:NG = 1:9NG

20010000510152025900
800700600500
40030050Si/PyC/CNF:NG = 5:550Si/PyC/CNF:NG = 3:750Si/PyC/CNF:NG = 2:850Si/PyC/CNF:NG = 1:9NG

200
10003005Cycle

The charge/discharge profiles of SWNT electrodes: (a) conventional slurry coatedelectrode and (b) “Free standing” electrode.

1015202530Cycle

Sample

1st cycle Coulombic
efficiency (%)

Retention ratio(%, 30th/1st )Sample

1st cycle Coulombic
efficiency (%)

Retention ratio(%, 30th/1st )20Si/PyC/CNF:NG=5:5

63.6

86.3

50Si/PyC/CNF:NG=5:5

63.1

81.4

20Si/PyC/CNF:NG=3:720Si/PyC/CNF:NG=2:820Si/PyC/CNF:NG=1:9

67.5
74.2
80.3

92.6
94.5
97.7

50Si/PyC/CNF:NG=3:750Si/PyC/CNF:NG=2:850Si/PyC/CNF:NG=1:9

66.9
72.1
77.8

95.4
96.7
98.8

NG

90.0

106.9

NG

90.0

106.9

√ The hybrids of the Si/PyC/CNF and NG showed better cycle-ability than the hybrids ofSi/PyC and NG.
44112012/11/13

Highly stable Si-based multicomponent anodes for practical use inlithium-ion batteries
Jung-In Lee , Nam-Soon Choi and Soojin Park
Energy Environ. Sci., 2012,5, 7878-7882
Interdisciplinary School of Green Energy,Ulsan National
Institute of Science and Technology, Ulsan, Korea 689-798

まとめ• Bulk Carbon以外は、長所と共に短所も持っており、まだLi-ion電池用負極としては商品化されていない。
• 今後の研究によって短所が解決できれば、電池の特性はより改善できる。

Synthesis of an Si-based multicomponent from bulk SiO particles via thermal annealing in the presence of NaOH. (a) Schematic
illustration for the conversion of bare SiO to Si–SiO–SiO2 three-components, (b) SEM image of Si-based multicomponents, SEM image (c)and Raman spectrum (d) of carbon-coated Si-based multicomponents, (e) XRD patterns of Si-based multicomponents as a function ofNaOH amount, and (f) calculation of silica and silicon crystallite size as a function of NaOH amountElectrochemical performances of c-SiO and c-Si–SiO–SiO2 three-component electrodes. (a) Voltage profiles of c-SiO (black), c-Si-multi-20–1 (red), c-Si-multi-10–
1 (pink), and c-Si-multi-5–1 (blue). (b) dQ/dV plots of c-SiO and c-Si-multi-20–1 (red) in the first and second cycles. (c) Cycle performances of c-SiO (black), c-Simulti-20–1 (red), c-Si-multi-10–1 (pink), and c-Si-multi-5–1 (blue) at 0.1 C rate. (d) Rate capabilities of c-SiO and c-Si-multi-20–1 electrodes. The discharge rate
was fixed at a rate of 0.1 C12