A comparative experimental and theoretical

investigation on energy storage performance of

CoSe2, NiSe2 and MnSe2 nanostructures

Mansi Pathak,1 Dipti Tamang,2 Manikandan Kandasamy,3 Bramhananda Chakraborty, 4,.* and

Chandra Sekhar Rout, 1*

1 Centre for Nano and Material Science, Jain global campus, Jakkasandra, Ramanagaram,

Banglore - 562112, India.

2School of Basic Sciences, Indian Institute of Technology, Bhubaneshwar, India

3 Nonlinear Optical Materials Laboratory, School of Physics, Bharathidasan University,

Tiruchirappalli-620024, Tamil Nadu, India.

4High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre,

Mumbai- 400085, India.

Supporting information

Specific capacitance calculated using cyclic voltammetry,

1

Csp= areaunder the CV curve2 x scanrate x potential window xmass of electrode

Specific capacitance calculated using charge-discharge cycle,

Csp= current x dischargetimemass x potential window

Current/mass is given by current density i,e, A/g and discharge time/ potential window can be

obtained by the slope of the discharging curve from galvanostatic charge-discharge plot (∆t/∆V).

Energy density of symmetric cell is calculated using following formula,

Ed=12

Csp x( ΔV )2

Where, Csp is a specific capacitance calculated from GCD and ΔV is the potential window.

(Wh/kg)

Power density of symmetric cell is calculated by using following formula,

Pd=EdΔt

Where, Ed is the energy density and Δt is the discharging time. (W/kg)

2

Results and discussion:

Figure S1: (a-b) FESEM images of CoSe2 at different magnifications, (c) EDAX spectrum of CoSe2

Figure S2: (a-b) FESEM images of NiSe2 at different magnifications, (c) EDAX spectrum of

NiSe2

3

Figure S3: (a-b) FESEM images of MnSe2 at different magnifications, (c) EDAX spectrum of

MnSe2.

4

Figure S4: (a) Survey spectrum of NiSe2 , (b) Ni 2p, (c and f) Se 3d, (d) Survey spectrum of

CoSe2 and (e) Co 2p.

Figure S 5 : Raman spectra pattern of CoSe2 and NiSe2.

5-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4

-0.003

-0.002

-0.001

0.000

0.001

0.002

0.003

Curr

ent (

A)

Potential (V)

2mV/s 5mV/s 10mV/s 20mV/s 40mV/s 80mV/s 100mV/s

(a)

0 50 100 150 200 250

-0.2

0.0

0.2

0.4

Pote

ntia

l (V)

Time (s)

0.2A/g 0.3A/g 0.5A/g 0.8A/g 1A/g 2A/g

(b)

Figure S6 : (a) CV curves CoSe2 at different scan rates and (b) GCD curves of CoSe2 at

different current densities

Figure S7 : (a) CV curves NiSe2 at different scan rates and (b) GCD curves of NiSe2 at different

current densities

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-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4-2.0m

-1.0m

0.0

1.0m

2.0m

Curr

ent (

A)

Potential (V)

2mV/s 5mV/s 10mV/s 20mV/s 40mV/s 80mV/s 100mV/s

(a)

0 100 200 300 400 500 600

-0.2

0.0

0.2

0.4

Pote

ntia

l (V)

Time (s)

0.1A/g 0.2A/g 0.3A/g 0.5A/g 0.8A/g 1A/g 2A/g

(b)

-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3

-400.0µ

-200.0µ

0.0

200.0µ

400.0µ

Curr

ent(

A)

Potential (V)

2mV/s 5mV/s 10mV/s 20mV/s 40mV/s 80mV/s 100mV/s

(a)

0 20 40 60 80 100 120 140

-0.2

0.0

0.2

Pote

ntia

l (V)

Time (s)

0.08A/g 0.1A/g 0.2A/g 0.3A/g 0.5A/g 0.8A/g 1A/g

(b)

Figure S8 : (a) CV curves MnSe2 at different scan rates and (b) GCD curves of MnSe2 at

different current densities

Table S1. Comparison of lattice parameters with the reported works.

Samples Lattice parameters (Å)a b c

CoSe2 4.88(4.850)7

5.81(5.827)7

3.64(3.628)7

NiSe2 5.94(5.960)8

5.94(5.960)8

5.94(5.960)8

MnSe2 6.28(6.417)9

6.28(6.417)9

6.28(6.417)9

Figure S9 : DFT optimized structure of (a) CoSe2 (101), (b) NiSe2 (200) (c) and MnSe2 (200).

Violet, red, pink and blue represent Co, Ni, Mn and Se respectively.

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Figure S10 : Ragone plot

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(b)

(c)

(a)

Figure S11. Charge density plots: (a) CoSe2, (b) NiSe2 (c) MnSe2. Violet, green, blue and red

color indicate Co, Ni, Mn and Se atom, respectively; yellow is the charge density iso-surfaces

with iso-value 0.08e.

Figure S12. XRD taken after electrochemical measurements: (a) CoSe2, (b) NiSe2 and (c)

MnSe2.

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