Host dimensionality

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Intercalate type

http://www.cem.msu.edu/~pinnweb/research-na.htm

Single-sheet inorganic colloidal dispersions are common and easily prepared

Ion exchange: (fixed charge density)

smectite clays Nax+yAl2-yMgySi4-

xAlxO10(OH)2

layered double hydroxides Mg3Al(OH)8Cl

layered oxides CsxTi2-x/4x/4O4

metal phosphorous sulfides K0.4Mn0.80.2PS3

Redox reaction: (variable charge density)

metal dichalocogenides LixMoS2

layered oxides LixCoO2 , NaxMoO3

Intercalation/exfoliation Reducing Polar Solvent agent (e.g. H2O) MS2 AxMS2 colloidal MS2

x-

Add polymer solution Nanocomposite (PEO polymer shown)

OOO

OOO

OOO

OOO

Graphite exfoliation

Layered chalcogenide exfoliation

Can we make colloidal [graphenium]+ or [graphide]- sheets

…if you have the correct sheet charge density and an appropriate polar solvent

Intercalation compound Swollen Colloidal

No solvation solvent in galleries solvated ions/sheetsL > solv solv > L

higher surface charge density

lower surface charge density

6

Graphite structure C-C in-plane = 1.42 Å Usually (AB)n hexgonal

stacking Interlayer distance

= 3.354 Å

http://www.ccs.uky.edu/~ernst/

A

B

A

Graphite is a semi-metal, chemically stable, light, strong

7

Li ion battery chemistry

Cathode LiCoO2 Li1-xCoO2 + xLi+ + xe-

Anode6C + Li+ + e- C6Li

ElectrolyteOrganic solvent with LiPF6

8

Selected rechargeable batteries

C. Pillot, BATTERIES 2009, Cannes, 2009

9

Graphite Lithiation

Graphite lithiation: approx 0.2-0.3 V vs Li+/Li

  Theoretical capacity: Li metal > 1000 mAh/g C6Li 370

Actual C6Li formation: 320 – 340 mAh/g reversible; 20 – 40 irreversible

Expands about10% along z

10

Theoretical capacity: Li metal > 1000 mAh/g C6Li 370

Typical C6Li formation: 320 – 340 reversible;

20 – 40 irreversible

Li arrangement in C6Li

Li+ occupies hexagon centers of non-adjacent hexagons

Next decade projections

11

Telsa battery packhttp://

www.teslamotors.com

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GIC’s

Reduction M+Cx-

 Group 1 except Na  

Oxidation Cx+An-

F, Br3-, O (OH)

BF4-, P BiF6

- , GeF62- to PbF6

2-, MoF6-, NiF6

2-, TaF6-, Re PtF6

-

SO4-, NO3

-, ClO4-, IO3

-, VO43-, CrO4

2-

AlCl4-, GaCl4-,FeCl4-, ZrCl6-,TaCl6-

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Staging and dimensions

Ic = di + (n - 1) (3.354 Å)

For fluoro, oxometallates di ≈ 8 A, for chlorometallates di ≈ 9-10 A

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Graphite oxidation potentials

H2O oxidation potential vs Hammett acidity

Colored regions show the electrochemical potential for GIC stages.

0.9

1.1

1.3

1.5

1.7

-7 -5 -3 -1 1 3 5

H0

E /

V

stage 1 GIC

stage 2

stage 3

high stage

no intercalation

49% hydrofluoric acidAll GICs are

unstable in ambient atmosphere , they oxidize H2O

New syntheses: chemical method

   

N S

O

O

CF3S

O

O

F3C ..

Cx + K2MnF6 + LiN(SO2CF3)2 CxN(SO2CF3)2 + K2LiMnF6oxidant anion source GIC

1,2

1. 48% hydrofluoric acid, ambient conditions

2. hexane, air dry

Oxidant and anion source are separate and changeable. Surprising stability in 50% aqueous acid.

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CxN(SO2CF3)2 chem prepn

5 15 25 35 45 55

2 / deg

Inte

n /

arb

un

its

15 sec

1 min

2 min

4 min

8 min

12 min

15 min

4 wks

graphite

   

0

20

40

60

80

100

120

0.1 1 10 100 1000 10000reaction time (h)

x

New syntheses: N(SO2CF3)2 orientation

F

F

F

F

Increasing F anion co-intercalate with reaction time

0

0.2

0.4

0.6

0.8

1

0 200 400 600

time / h

dF

CxN(SO2CF3)2· dF Katinonkul, Lerner

Carbon (2007)

New syntheses: imide intercalates

Anion mw di / nm

1. N(SO2CF3)2 280 0.812. N(SO2C2F5)2 380

0.823. N(SO2CF3)(SO2C4F9) 430

0.83

1

23

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CxN(SO2CF3)2 echem prepn

2.0

3.0

4.0

5.0

6.0

0 100 200 300 400 500 600

Capacity (mAh/g)

V v

s Li

+/L

icharge discharge

ab c

d e

100

4.30 4.70 5.10V vs Li+/Li

dQ

/dV

2 13 2

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CxN(SO2CF3)2 - echem prepn

4.0

4.5

5.0

5.5

6.0

0 100 200 300 400

Charge (mAh/g)

V v

s L

i+/L

i

(a)(b)

a

bc

d e

b

dCxPFOS

CxN(SO2CF3)2

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Imide (NR2-) intercalates

Anion MW di / Å

N(SO2CF3)2 280 8.1

N(SO2C2F5)2 380 8.2

N(SO2CF3) 430 8.3

(SO2C4F9)

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CxPFOS - preparation

Cx+ K2Mn(IV)F6 + KSO3C8F17

CxSO3C8F17 + K3Mn(III)F6

(CxPFOS)

Solvent = aqueous HF3.35 A

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CxPFOS intercalate structure

Anions self-assemble as bilayers within graphite galleries

New syntheses: CxSO3C8F17

Domains are 10-20 sheets along stacking direction

1.12

0.78 nm

CxB(O2C2O(CF3)2)2

Stage 2

1.13

0.85 nm

Stage 1

CxB(O2C2(CF3)4)2

Borate chelate GIC’s

Blue: obsPink: calc

Unexpected anion orientation - long axis to sheets

T