Supporting information ACS

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One step synthesis of Si@C nanoparticles by

laser pyrolysis: high capacity anode material

for lithium ion batteries

Julien Sourice1,2*, Axelle Quinsac

1, Yann Leconte

1, Olivier Sublemontier

1, Willy Porcher

2,

Cedric Haon2, Arnaud Bordes

3, Eric De Vito

3, Adrien Boulineau

2,

Séverine Jouanneau Si Larbi2, Nathalie Herlin-Boime

1*, Cécile Reynaud

1

1CEA, IRAMIS, NIMBE, CNRS UMR 3685, F- 91191, Gif sur Yvette, France

2Univ. Grenoble Alpes, F-38000, Grenoble, France

2CEA, LITEN, 17 rue des Martyrs, F-38054 Grenoble, France

3CEA, MINATEC, 17 rue des Martyrs, F-38054 Grenoble, France

Corresponding authors: Julien Sourice (julien.sourice@cea.fr), Dr. Nathalie Herlin-Boime

(nathalie.herlin@cea.fr)

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Carbon capacity in Si@C material

The capacity of the carbon was considered negligible based on the following analysis.

Figure S1 shows 10 cyclic voltammetry sweeps of Si@C in the potential windows 5 mV to

250 mV in order to limit the lithiation to the carbon shells and carbon nanoparticles only. The

anodic (0.8 and 0.5 V) and cathodic current peaks (0.11, 0.15 and 0.2 V) are the classical

signature of lithiation and delithiation from carbon species, therefore proving that the

potential window is correctly chosen (according with I. Uchida et al., Electrochemical and

Solid-State Letters, 1 (1) 10-12, 1998). The capacitive current is due to lithium adsorption on

carbonaceous material.

Figure S1: Cyclic voltammetry (20 µV.s-1

) of Si@C material in the potential window 5 mV

to 250 mV

Based on the precedent result, Figure S2 shows the capacity from the galvanostatic

experiment (C/10 charge/discharge rate) on the same Si@C material and in the same potential

window. The capacity related to carbon species in Si@C reaches approximately 100 mAh.g-1

.

Therefore, we chose not to include the masses of carbon compounds into the calculus of

Si@C specific capacity as their impact on the total capacity can be neglected.

S1

0,00 0,05 0,10 0,15 0,20 0,25

-0,04

-0,02

0,00

0,02

0,04

Intensity [mA]

Potential [V]

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Figure S2: Galvanostatic cycling (C/10) of Si@C sample in the potential window 5 mV to

250 mV

Si@C Raman spectra deconvolution

Deconvolution of Raman spectra of Si@C has been conducted with 100% Lorentzian function

based on A. Santamaria work (Raman features between two classes of carbon nanoparticles

generated in ethylene flames, XXXVI Meeting of the Italian Section of the Combustion

Institute). Figure S3 shows the 5 contributions extracted from the 1100 to 1700 cm-1

Raman

signals and Table S1 report their centers, widths and heights.

Center

[cm-1]

Width

[cm-1]

Height

[arb.uni.]

G 1578 83 1655

D1 1350 180 1681

D2 1602 59 852

D3 1483 95 216

D4 1246 215 408

Table S1: Centers, widths and heights of G, D1, D2, D3 and D4 signals deconvoluted from

the Raman signal of Si@C in the 1100 to 1700cm-1

area.

S2

10 20 30 40 50 60 70 80 90 1000

50

100

150

200

250

300

350

400

delithiation

lithiation

Capacity (mAh.g-1)

Cycle

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Figure S3: Raman spectra of Si@C and the 5 contributions G, D1, D2, D3 and D4 obtained

from the fit analysis

EELS spectra

The EELS spectra associated to the mapping of Si@C nanoparticle of Figure 2f is displayed

in Figure S4. The two features at 285 eV and 290 eV are identified as transitions to the π*

molecular orbital and to σ* orbitals respectively.

Figure S4: EELS spectra of Si@C and insert highlighting C K edge π* and σ*

Additional TEM, HRTEM and SEM images

1000 1200 1400 1600 1800-700

0

700

1400

2100

Intensity [a.u.]

Raman shift [cm-1]

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Figure S5: HRTEM, TEM and SEM images of Si@C (a,b,c and d) and Si (e, f, g and h)

samples

Charge discharge curves

Figure S6: First lithiation/delithiation curves of Si sample (C/10)

0 1000 2000 3000 4000 5000

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

Voltage (V)

Capacity (mAh.g-1)

Si

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Figure S7: First lithiation/delithiation curves of Si@C sample (C/10)

0 1000 2000 3000 4000 5000

0,0

0,5

1,0

1,5

2,0

2,5

3,0

Voltage (V)

Capacity (mAh.g-1)

Si@C