1

Supporting Information

Free-standing NiV2S4 nanosheet arrays on 3D Ni framework via anion exchange

reaction as a novel electrode for asymmetric supercapacitor applications

Rudra Kumar, Prabhakar Rai*, Ashutosh Sharma*

Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur

208016, India

*E-mail: prkrai@iitk.ac.in, ashutos@iitk.ac.in

Figure S1. SEM, elemental mapping, and EDX spectrum of Ni3(VO4)2 nanosheet arrays.

cps

Energy (keV)

EDX

Ni

V O

SEM

500 nm

Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A.This journal is © The Royal Society of Chemistry 2016

2

Figure S2. SEM, elemental mapping, and EDX spectrum of NiV2S4 nanosheet arrays.

Ni

V S

O

cps

Energy (keV)

EDX

SEM

500 nm

Figure S3. XRD profile of as synthesized NiV2S4 nanosheet arrays along with curve from

standard PDF card.

10 20 30 40 50 60 70 80

NiV2S4

JCPDS No- 00-076-1058

2θ (Degree)

Inte

nsity

(a. u

.)

(105

)

(110

)(-

112)

(-21

3)

(310

)(-

215) (-

305)

(123

)

(-12

5)(3

16)(102

)

(305

)

3

Figure S4. XPS spectra of Ni3(VO4)2 nanosheet arrays; a) survay, b) Ni, c) V and d) O.

1000 800 600 400 200 0

Ni3(VO4)2 NiV2S4

885 880 875 870 865 860 855 850

526 524 522 520 518 516 514 512

cps

Binding Energy (eV)

V 2

p 1/2

cps C

1s

V 2

p3V

2p1N

i LM

MN

i LM

M1

Ni L

MM

2N

i 2P3

Ni 2

P1O

KLL

Ni 2

s

cpsN

i 3p

V3pNi 3

s

(a)

Binding Energy (eV)(c)

O1s

(b)

Ni 2

p 3/2

Ni 2

p 1/2

Sate

llite

Sate

llite

533 532 531 530 529 528 527 526 525

Binding Energy (eV)

O 1

s

cps

(d)

V 2

p 3/2

Binding Energy (eV)C

1s

V 2

p3 V 2

p1

Ni L

MM

Ni L

MM

1N

i LM

M2

Ni 2

P3N

i 2P1

S 2p Ni 3

pV

3pNi 3

s

S 2s

V L

MM

2V

LM

MV

LM

M1

O1s

Figure S5. BET surface area and pore size distribution of (a) Ni3(VO4)2 and (b) NiV2S4

nanosheet arrays.

0.0 0.2 0.4 0.6 0.8 1.0

406080

100120140160180200220

0 5 10 15 20 25 30 35

0.00

0.05

0.10

0.15

0.20

Pore Diameter (nm)

dV(d

) (cc

/nm

/g)

0.0 0.2 0.4 0.6 0.8 1.05

10

15

20

25

30

35

40

45

0 5 10 15 20 25 300.00

0.01

0.02

0.03

0.04

dV(d

) (cc

/nm

/g)

Pore Diameter (nm)

Relative Pressure (P/Po) Relative Pressure (P/Po)

Volu

me@

STP

(cc/

g)

Volu

me@

STP

(cc/

g)

(a) (b)

4

Figure S6. (a) CV and (b) GCD curve of Ni3(VO4)2 nanosheet arrays.

0.0 0.1 0.2 0.3 0.4 0.5

-0.10

-0.05

0.00

0.05

0.10 5mV/s 10mV/s 20mV/s 30mV/s 50mV/s

0 100 200 300 400 500 6000.0

0.1

0.2

0.3

0.4 2mA/cm2

5mA/cm2

10mA/cm2

15mA/cm2

20mA/cm2

30mA/cm2

40mA/cm2

50mA/cm2

Cur

rent

(A)

Potential (V)

Pote

ntia

l (V

)

Time (sec.)

(a) (b)

Figure S7. GCD curve of Ni3(VO4)2 nanosheet arrays synthesized at different times.

0 100 200 300 400 500 6000.0

0.1

0.2

0.3

0.4 6h 12h 18h 24h

2 mA/cm2

Pote

ntia

l (V

)

Time (sec.)

Figure S8. (a) Nyquist plot (inset shows high frequency region) and (b) I-V curve

measurement of NiV2S4 and Ni3(VO4)2 nanosheet arrays.

0 5 10 15 20 25 30

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Ni3(VO4)2 NiV2S4

Current (mA)

Volta

ge (

mV

)

0 200 400 600 8000

200

400

600

800 NiV2S4 Ni3(VO4)2

-Z"

(Ω)

(a)

Z' (Ω)

(b)

0.5 1.0 1.5 2.00

1

2

3

4

5

6

-Z" (

)

Z' ()

NiV2S4 NI3(VO4)2

5

Figure S9. Long term cycling stability of NiV2S4 nanosheet array at 50 mVs-1.

0.0 0.1 0.2 0.3 0.4 0.5

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15 1st 100th 200th 400th 500th

Cur

rent

(A)

Potential (V)

Figure S10. Rate capability of NiV2S4 nanosheet array.

0 500 1000 1500 2000 25000

100

200

300

400

500

600

700

5 mA/cm2

50 mA/cm2

30 mA/cm2

5 mA/cm2

15 mA/cm2

2 mA/cm2

15 mA/cm2

Spec

ific

capa

city

(C/g

)

No. of cylces

Figure S11. Cycling performance of Ni3(VO4)2 nanosheet array at (a) 10 mAcm-2 current

density for 2000 cycles and (b) 5 mA.cm-2 for 500 cycles .

0 100 200 300 400 5000

20

40

60

80

1005 mA/cm2

0 500 1000 1500 20000

20

40

60

80

100 10 mA/cm2

Cap

acity

Ret

entio

n (%

)

Cap

acity

Ret

entio

n (%

)

No of cycle No of cycle

(a) (b)

6

Figure S12. SEM images of (a) Ni3(VO4)2, (b) NiV2S4, and (c) EIS of NiV2S4 after cycling

performance at 10 mAcm-2 and 30 mAcm-2 current density, respectively for 2000 cycles.

(a) (b)

500 nm 200 nm

Figure S13. EIS of NiV2S4 after cycling performance at 30 mAcm-2 current density for 2000

cycles.

0 50 100 150 200 250 3000

50

100

150

200

250

300

350

400

-Z

" (Ω

)

Z' (Ω)

0.2 0.4 0.6 0.8 1.00

1

2

3

4

5

Z' ()

-Z" (

)

Figure S14. (a) CV curves at different scan rates (5-50 mVs-1), (b) GCD curves at different

current densities (1-5 Ag-1) and c) Variation of specific capacity with respect to different

current densities for AC.

-1.0 -0.8 -0.6 -0.4 -0.2 0.0-0.04

-0.02

0.00

0.02

0.04

5mV/s 10mV/s 20mV/s 30mV/s 40mV/s 50mV/s

0 100 200 300 400-1.0

-0.8

-0.6

-0.4

-0.2

0.0 1A/g 2A/g 4A/g 5A/g

1 2 3 4 50

50

100

150

200(a)

Potential (V)

Cur

rent

(A)

Pote

ntia

l (V

)

Time (sec.)

Spec

ific

Cap

acity

(C/g

)

(b)

(c)

Current Density (A/g)

7

Figure S15: CV of NiV2S4 //AC asymmetric supercapacitor at 10 mVs-1 at different potential

window (1- 1.6 V).

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6-0.015

-0.010

-0.005

0.000

0.005

0.010

0.015

1 V 1.2 V 1.4 V 1.6 V

Cur

rent

(A)

Potential (V)

Table S1. Comperative study of different asymmetric supercapacitor performance reported in

literature with respect to our electrode.

Asymmetric Supercapacitor Voltage

(V)

Energy

Density

(Whkg-1)

Power

Density

(Wkg-1)

Cyclic

Stability

Ref No

Ni-Co-S nanosheet

arrays//graphene

1.8 60 1800 90.1% (10,000) 1

NiCo2S4 nanotube arrays/Ni

foam//RGO

1.6 16.6 2350 92% (5000) 2

Ni3(VO4)2//AC 1.6 25.3 240 92% (1000) 3

3D Ni3S2 nanosheet arrays on

Ni foam//AC

1.6 34.6 150.4 85.7 % (1000) 4

NiCo2S4@Ni3V2O8 on Ni

foam//AC

1.6 42.7 200 90% (5000) 5

NiCo2S4//AC 1.5 28.3 245 91.7% (5000) 6

8

Ni(OH)2/graphene//graphene 1.6 77.8 175 94%(3000) 7

Co9S8 nanoflakes//AC 1.6 31.4 200 90% (5000) 8

Core-shell NiCo2S4//C 1.6 22.8 160 9

Hollow hetero Ni7S6/Co3S4

nanoboxes//AC

1.5 31 180 86% (5000) 10

rGO-Ni3S2//AC 1.6 37.19 399.9 85.6% (5000) 11

Ni@rGO−Co3S4//

Ni@rGO−Ni3S2

1.3 55.16 965 96.2 % (3000) 12

Capsule-like porous hollow

Ni1.77Co1.23S4 // AC

1.6 42.7 190.8 13

Ni–Co sulphide nanowires//AC 1.8 25 447 73.1% (3000) 14

NiV2S4//AC 1.6 45.2 240 90.7% (1000) This Work

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