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Layered Ternary Sulfide CuSbS2 Nanoplates for Flexible Solid-State Supercapacitors

Karthik Ramasamy,1* Ram. K. Gupta,2 Hunter Sims,3 Soubantika Palchoudhury,4 Sergei Ivanov,1

Arunava Gupta4*

1Center for Integrated Nanotechnologies, Los Alamos National Laboratory,

Albuquerque, NM-87185

2Department of Chemistry, Pittsburg State University, Pittsburg, KS-66762.

3German Research School for Simulation Science, Jülich, Germany-524254Center for Materials for Information Technology, The University of Alabama,

Tuscaloosa, AL-35487

Supporting Information

Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A.This journal is © The Royal Society of Chemistry 2015

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Figure S1. (a) XPS survey spectrum of CuSbS2 nanoplates. (b)-(d) High resolution XPS spectra of Cu, Sb and S, respectively.

545 540 535 530 525 520

eV

3d3/2

3d5/2

Inte

nsity

(a.u

)

Binding Energy (eV) 166 164 162 160 158 156

eV 2p3/2

2p1/2

In

tens

ity (a

.u)

Binding Energy (eV)

965 960 955 950 945 940 935 930 925

eV

Binding Energy (eV)In

tens

ity (a

.u)

2p1/2

2p3/2

0 200 400 600 800 1000 1200

Inte

nsity

(a.u

)

Binding Energy (eV)

CuSbS2 survey (a) (b)

(c) (d)

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Figure S2. (a) and (b) Top and side view HRTEM images of a CuSbS2 nanoplate. (c) and (d) Fast Fourier transform (FFT) of HRTEM images shown in (a) and (b). (e) and (f) TEM images of 55 ± 6.5 nm and 105 ± 5.5 nm nanoplates

(a) (b)

(c) (d)

(e) (f)

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Figure S3. Cyclic voltammogram curves of CuSbS2 at various scan rates using KOH as electrolyte.

0.2 0.3 0.4 0.5 0.6

-25.0

0.0

25.0

50.0 50 mV/s 75 mV/s 100 mV/s 125 mV/s 150 mV/s

Curr

ent (

A/g)

Potential (V, vs SCE)

5 mV/s 10 mV/s 20 mV/s 30 mV/s 40 mV/s

5

.

Figure S4. Plots of the anodic and cathodic wave current versus the square root of the scan rate.

2 4 6 8 10 12 14-40

-20

0

20

40 Anodic Current Cathodic Current

Peak

Cur

rent

(A/g

)

Square root of scan rate (m1/2V1/2/s1/2)

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Figure S5. SEM images of (a) 7.2 ± 1.4 nm and (b) 19 ± 1 nm thick CuSbS2 nanoplates.

(a) (b)

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Figure S6. Intercalated K ion in van der Waals gap of CuSbS2. The adsorbed ion has taken the place of its nearest Sb ion, which is pushed into the interior of the layer. Cu sites are blue, Sb are orange, and S are yellow.

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Figure S7. (a) Cyclic voltammogram curves of CuSbS2 nanoplates at different bending angles.

0.2 0.3 0.4 0.5 0.6

-8.00

-4.00

0.00

4.00

8.00

12.00

Curr

ent (

A/g)

Potential (V)

0o

15o

30o 45o

CuSbS2 @3M LiOH

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Figure S8. (a) Cyclic voltammogram curves of CuSbS2 nanoplate supercapacitor device at different temperatures using LiOH. (b) A graph showing changes in specific capacitance with temperatures. Specific capacitance values are deduced from the CV curves. (c) Galvanostatic discharge characteristics of CuSbS2 nanoplate device at different temperatures. (d) A graph showing change in specific capacitance with temperature. Csp was calculated from the galvonostatic charge-discharge measurements.

10 20 30 40 50 60-20

0

20

40

60

80

Room Temperature

Chan

ge in

Sp.

Cap

acita

ne (%

)Temperature (oC)

0.2 0.3 0.4 0.5 0.6

-5x10-4

0

5x10-4

1x10-3

2x10-3

Curr

ent (

A/cm

2 )

Potential (V)

15 C 25 C 35 C 45 C 55 C

0 1 2 3 4 50.0

0.2

0.4

0.6

Pote

ntia

l (V)

Time (s)

15 C 25 C 35 C 45 C 55 C

10 20 30 40 50 60

0

20

40

60

80Room Temperature

Chan

ge in

Sp.

Cap

acita

nce (

%)

Temperature (oC)

(a) (b)

(c)(d)