A self-driven alloying/dealloying approach to nanostructuring micro-silicon

for high-performance lithium-ion battery anodes

Qiang Maa, Zhuqing Zhaoa, Yan Zhaoa, Hongwei Xiea, Pengfei Xinga, Dihua Wangc, and

Huayi Yina,b,*

a Key Laboratory for Ecological Metallurgy of Multimetallic Mineral of Ministry of Education,

School of Metallurgy, Northeastern University, Shenyang 110819, P. R. China.

b Key Laboratory of Data Analytics and Optimization for Smart Industry, Ministry of Education,

Northeastern University, Shenyang 110819, P. R. China.

c School of Resource and Environmental Science, Wuhan University, Wuhan, 430072, P. R. China.

* Corresponding author. Email: yinhy@smm.neu.edu.cn (Huayi Yin)

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Fig. S1. Optical image of (a) the Mg-Si alloy electrode formed after soaking in molten salt for 1.5 h

(the inset is the treated Mg-Si alloy powders). (b) XRD pattern of the as-soaked alloy negative

product. For reference, the standard powder XRD pattern of Mg2Si was also included.

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Fig. S2. Digital images of the (a) mSi, (b) nSi-2, (c) nSi-1.5, (d) nSi-1, and (e) nSi-0.5.

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Fig. S3. (a) Optical image of the formed Mg-Sn alloy electrode (the inset is the obtained Mg-

Sn alloy blocks). (b) XRD pattern of the as-obtained positive product. For reference, the

standard powder XRD patterns of Mg2Sn and Sn were also included.

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Fig. S4. SEM image of the as-obtained Mg-Sn alloy (a) and corresponding EDS elemental

maps of Mg (b) and Sn (c).

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Fig. S5. XRD pattern of the as-vacuum-distillated sample. For reference, the standard powder

XRD pattern of Sn was also included. The inset shows the optical images of the samples

before and after vacuum distillation.

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Fig. S6. (a) SEM image PCC-nSi-2, corresponding Si (b), C (c), N (d) elemental mapping

images.

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Fig. S7. XRD patterns of mSi, nSi-1.5, nSi-1, and nSi-0.5.

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Fig. S8. FTIR spectra of the melamine-formaldehyde resin (MR).

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Fig. S9. The galvanostatic charge-discharge profiles for the first cycle of mSi and nSi-2

electrodes at 0.6 A g-1.

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Fig. S10. Cycling performance and the corresponding Coulombic efficiency of the pyrolytic

carbon (MR) electrode at 0.6 A g-1.

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Fig. S11. Galvanostatic charge/discharge profiles of PCC-nSi-2 at current density of (a) 1 and

(b) 2 A g-1, respectively.

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Table S1. Si, C, N, and O element content (%) obtained from XPS

SamplesElement content (atom%)

Si C N O

PCC-nSi-2 22.64 55.04 10.09 11.42

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Table S2. Electrochemical performance and synthesis method comparison of Si-based anode

materials in LIBs.

Materialsstructure

Synthesismethod

Cycling performance

Ref.Specificcapacity

Cyclenumber

Current/rate

Porous silicon/CLow temperature Al2O3 catalyzed

method

1024 mAh g-1

600 cycles 1 A g-1 [1]

Si/N-doped carbonAssisted

electrospray method

1031 mAh g-1

100 cycles 0.5 A g-1 [2]

Porous Si@CReduction in molten AlCl3

600mAh g-1

3700 cycles 2 A g-1 [3]

Porous Si@CElectrolysis inAlCl3-ZnCl2

molten salt

~ 2100 mAh g-1

250 cycles 1.2 A g-1 [4]

Si@CMg2Si oxidation,

HCl washing892

mAh g-1350 cycles 3.6 A g-1 [5]

Low-cost Si/C nanofibers

Ball-milled and carbonization

1595 mAh g-1

100 cycles 0.4 A g-1 [6]

Si NPs/C/graphiteAqueous sol-gel

system and carbonization

820mAh g-1

100 cycles 0.1 A g-1 [7]

Si/CFlash heat treatment

1150 mAh g-1

500 cycles 1.2 A g-1 [8]

Si/PDAMolten salt

reduction and carbonization

886.2 mAh g-1

200 cycles 0.5 A g-1 [9]

Si/CMg2Si and CO2

acid washing~1124

mAh g-1100 cycles 0.4 A g-1 [10]

Si NPs/CarbonMR, acid etching and carbonization

~1467 mAh g-1

370 cycles 2.6 A g-1 [11]

PCC-nSi-2self-driven

alloying/dealloying in molten salt

1406.5 mAh g-1

400 cycles 0.6 A g-1

This work

1080.2 mAh g-1

1000 cycles 1 A g-1

912.2 mAh g-1

1000 cycles 2 A g-1

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Table S3. Equivalent series resistance (Re) and charge transfer resistance (Rct) of the mSi, nSi-

2, and PCC-nSi-2.

Samples Re (Ω) Rct (Ω)

mSi 7.4 79.1

nSi-2 5.3 64.8

PCC-nSi-2 3.1 45.6

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