Abstract

In this study, molten-salt electrolysis of silica was investigated to identify the role played by electrolytic conditions on the deoxidization depth. Four key conditions that included particle size, electrolytic temperature, working time, and cell voltage were systematically compared using X-ray diffraction, scanning electron microscopy (SEM), field-emission SEM, transmission electron microscopy, and X-ray photoelectron spectroscopy analyses. The results suggest that prolonging the cell voltage is another key factor that determines the reduction process. Based on the given current conditions, the order of effect on the experiment is working time, cell voltage, electrolytic temperature, and particle size. The obtained specimen under optimized condition is Si and Fe–Si alloy composite with silicon porous nanosphere and Fe–Si nanoparticles in a structure that is prepared using 10 nm SiO2 nanosphere as a raw material at 800 °C for 5 h at a cell voltage of 2.6–2.8 V. The present research provides a promising guidance for practical application using the method of molten-salt electrolysis.

References

1.
Sun
,
Y.
,
Liu
,
N.
, and
Cui
,
Y.
,
2016
, “
Promises and Challenges of Nanomaterials for Lithium-Based Rechargeable Batteries
,”
Nat. Energy
,
1
(
7
), p.
16071
.
2.
Schmuch
,
R.
,
Wagner
,
R.
,
Horpel
,
G.
,
Placke
,
T.
, and
Winter
,
M.
,
2018
, “
Performance and Cost of Materials for Lithium-Based Rechargeable Automotive Batteries
,”
Nat. Energy
,
3
(
4
), pp.
267
278
.
3.
Jin
,
Y.
,
Zhu
,
B.
,
Lu
,
Z.
,
Liu
,
N.
, and
Zhu
,
J.
,
2017
, “
Challenges and Recent Progress in the Development of Si Anodes for Lithium-Ion Battery
,”
Adv. Energy Mater.
,
7
(
23
), p.
1700715
.
4.
Armand
,
M.
, and
Tarascon
,
J. M.
,
2008
, “
Building Better Batteries
,”
Nature
,
451
(
7179
), pp.
652
657
.
5.
Cano
,
Z. P.
,
Banham
,
D.
,
Ye
,
S.
,
Hintennach
,
A.
,
Lu
,
J.
,
Fowler
,
M.
, and
Chen
,
Z.
,
2018
, “
Batteries and Fuel Cells for Emerging Electric Vehicle Markets
,”
Nat. Energy
,
3
(
4
), pp.
279
289
.
6.
Su
,
X.
,
Wu
,
Q.
,
Li
,
J.
,
Xiao
,
X.
,
Lott
,
A.
,
Lu
,
W.
,
Sheldon
,
B. W.
, and
Wu
,
J.
,
2014
, “
Silicon-Based Nanomaterials for Lithium-Ion Batteries: A Review
,”
Adv. Energy Mater.
,
4
(
1
), p.
1300882
.
7.
Ashuri
,
M.
,
He
,
Q.
, and
Shaw
,
L. L.
,
2016
, “
Silicon as a Potential Anode Material for Li-Ion Batteries: Where Size, Geometry and Structure Matter
,”
Nanoscale
,
8
(
1
), pp.
74
103
.
8.
Feng
,
K.
,
Li
,
M.
,
Liu
,
W.
,
Kashkooli
,
A. G.
,
Xiao
,
X.
,
Cai
,
M.
, and
Chen
,
Z.
,
2018
, “
Silicon-Based Anodes for Lithium-Ion Batteries: From Fundamentals to Practical Applications
,”
Small
,
14
(
8
), p.
1702737
.
9.
Li
,
P.
,
Zhao
,
G.
,
Zheng
,
X.
,
Xu
,
X.
,
Yao
,
C.
,
Sun
,
W.
, and
Dou
,
S. X.
,
2018
, “
Recent Progress on Silicon-Based Anode Materials for Practical Lithium-Ion Battery Applications
,”
Energy Storage Mater.
,
15
, pp.
422
446
.
10.
Nishimura
,
Y.
,
Nohira
,
T.
,
Kobayashi
,
K.
, and
Hagiwara
,
R.
,
2011
, “
Formation of Si Nanowires by Direct Electrolytic Reduction of Porous SiO2 Pellets in Molten CaCl2
,”
J. Electrochem. Soc.
,
158
(
6
), pp.
E55
E59
.
11.
Li
,
K.
,
Xie
,
H.
,
Liu
,
J.
,
Ma
,
Z.
,
Zhou
,
Y.
, and
Xue
,
D.
,
2013
, “
From Chemistry to Mechanics: Bulk Modulus Evolution of Li-Si and Li-Sn Alloys Via the Metallic Electronegativity Scale
,”
Phys. Chem. Chem. Phys.
,
15
(
40
), pp.
17658
17663
.
12.
Shavel
,
A.
,
Guerrini
,
L.
, and
Alvarez-Puebla
,
R. A.
,
2017
, “
Colloidal Synthesis of Silicon Nanoparticles in Molten Salts
,”
Nanoscale
,
9
(
24
), pp.
8157
8163
.
13.
Mi
,
H.
,
Yang
,
X.
,
Li
,
F.
,
Zhuang
,
X.
,
Chen
,
C.
,
Li
,
Y.
, and
Zhang
,
P.
,
2019
, “
Self-Healing Silicon-Sodium Alginate-Polyaniline Composites Originated From the Enhancement Hydrogen Bonding for Lithium-Ion Battery: A Combined Simulation and Experiment Study
,”
J. Power Sources
,
412
, pp.
749
758
.
14.
Cai
,
J.
,
Luo
,
X. T.
,
Lu
,
C. H.
,
Haarberg
,
G. M.
,
Laurent
,
A.
,
Kongstein
,
O. E.
, and
Wang
,
S. L.
,
2012
, “
Purification of Metallurgical Grade Silicon by Electrorefining in Molten Salts
,”
Trans. Nonferrous Met. Soc. China
,
22
(
12
), pp.
3103
3107
.
15.
Cho
,
S. K.
,
Fan
,
F. R. F.
, and
Bard
,
A. J.
,
2012
, “
Formation of a Silicon Layer by Electroreduction of SiO2 Nanoparticles in CaCl2 Molten Salt
,”
Electrochim. Acta
,
65
, pp.
57
63
.
16.
An
,
W.
,
Gao
,
B.
,
Mei
,
S.
,
Xiang
,
B.
,
Fu
,
J.
,
Wang
,
L.
,
Zhang
,
Q.
,
Chu
,
P. K.
, and
Huo
,
K.
,
2019
, “
Scalable Synthesis of Ant-Nest-Like Bulk Porous Silicon for High-Performance Lithium-Ion Battery Anodes
,”
Nat. Commun.
,
10
(
1
), p.
1447
.
17.
Jin
,
X.
,
Gao
,
P.
,
Wang
,
D.
,
Hu
,
X.
, and
Chen
,
G. Z.
,
2004
, “
Electrochemical Preparation of Silicon and Its Alloys From Solid Oxides in Molten Calcium Chloride
,”
Angew. Chem., Int. Ed.
,
43
(
6
), pp.
733
736
.
18.
Kim
,
H.
,
Seo
,
M.
,
Park
,
M.-H.
, and
Cho
,
J.
,
2010
, “
A Critical Size of Silicon Nano-Anodes for Lithium Rechargeable Batteries
,”
Angew. Chem., Int. Ed.
,
49
(
12
), pp.
2146
2149
.
19.
Dong
,
Y.
,
Slade
,
T.
,
Stolt
,
M. J.
,
Li
,
L.
,
Girard
,
S. N.
,
Mai
,
L.
, and
Jin
,
S.
,
2017
, “
Low-Temperature Molten-Salt Production of Silicon Nanowires by the Electrochemical Reduction of CaSiO3
,”
Angew. Chem., Int. Ed.
,
56
(
46
), pp.
14453
14457
.
20.
Cai
,
J.
,
Luo
,
X.-t.
,
Haarberg
,
G. M.
,
Kongstein
,
O. E.
, and
Wang
,
S.-l.
,
2012
, “
Electrorefining of Metallurgical Grade Silicon in Molten CaCl2 Based Salts
,”
J. Electrochem. Soc.
,
159
(
3
), pp.
D155
D158
.
21.
Xiao
,
W.
,
Wang
,
X.
,
Yin
,
H.
,
Zhu
,
H.
,
Mao
,
X.
, and
Wang
,
D.
,
2012
, “
Verification and Implications of the Dissolution–Electrodeposition Process During the Electro-Reduction of Solid Silica in Molten CaCl2
,”
RSC Adv.
,
2
(
19
), p.
7588
.
22.
Yang
,
X.
,
Ji
,
L.
,
Zou
,
X.
,
Lim
,
T.
,
Zhao
,
J.
,
Yu
,
E. T.
, and
Bard
,
A. J.
,
2017
, “
Toward Cost-Effective Manufacturing of Silicon Solar Cells: Electrodeposition of High-Quality Si Films in a CaCl2-Based Molten Salt
,”
Angew. Chem., Int. Ed.
,
56
(
47
), pp.
15078
15082
.
23.
Hu
,
L.
,
Yang
,
W.
,
Yang
,
Z.
, and
Xu
,
J.
,
2019
, “
Fabrication of Graphite Via Electrochemical Conversion of CO2 in a CaCl2 Based Molten Salt at a Relatively Low Temperature
,”
RSC Adv.
,
9
(
15
), pp.
8585
8593
.
24.
Sun
,
L.
,
Li
,
J.
,
Xu
,
R.
,
He
,
S.
,
Hua
,
Z.
, and
Liu
,
H.
,
2021
, “
One-Step Rapid Synthesis of a 3D Porous Surface on Zr-Based Bulk Metallic Glass
,”
Surf. Coat. Technol.
,
418
, p.
127230
.
25.
Ito
,
Y.
,
2000
, “
Some Approaches to Novel Molten Salt Electrochemical Processes
,”
Electrochemistry
,
68
(
2
), pp.
88
94
.
26.
Nohira
,
T.
, and
Ito
,
Y.
,
2001
, “
Synthesis of Monosilane by Molten Salt Electrochemical Process
,”
6th International Symposium on Molten Salt Chemistry and Technology
,
Shanghai, China
,
Oct. 8–13
, pp.
247
252
.
27.
Chen
,
K.
,
Hua
,
Y.
,
Xu
,
C.
,
Zhang
,
Q.
,
Qi
,
C.
, and
Jie
,
Y.
,
2015
, “
Preparation of TiC/SiC Composites From Ti-Enriched Slag by an Electrochemical Process in Molten Salts
,”
Ceram. Int.
,
41
(
9
), pp.
11428
11435
.
28.
Jiang
,
K.
,
Hu
,
X.
,
Ma
,
M.
,
Wang
,
D.
,
Qiu
,
G.
,
Jin
,
X.
, and
Chen
,
G. Z.
,
2006
, “
“Perovskitization”-Assisted Electrochemical Reduction of Solid TiO2 in Molten CaCl2
,”
Angew. Chem., Int. Ed.
,
45
(
3
), pp.
428
432
.
29.
Otake
,
K.
,
Kinoshita
,
H.
,
Kikuchi
,
T.
, and
Suzuki
,
R. O.
,
2013
, “
CO2 Gas Decomposition to Carbon by Electro-Reduction in Molten Salts
,”
Electrochim. Acta
,
100
, pp.
293
299
.
30.
Deng
,
B.
,
Chen
,
Z.
,
Gao
,
M.
,
Song
,
Y.
,
Zheng
,
K.
,
Tang
,
J.
,
Xiao
,
W.
,
Mao
,
X.
, and
Wang
,
D.
,
2016
, “
Molten Salt CO2 Capture and Electro-Transformation (MSCC-ET) Into Capacitive Carbon at Medium Temperature: Effect of the Electrolyte Composition
,”
Faraday Discuss.
,
190
, pp.
241
258
.
31.
Zou
,
X.
,
Ji
,
L.
,
Hsu
,
H.-Y.
,
Zheng
,
K.
,
Pang
,
Z.
, and
Lu
,
X.
,
2018
, “
Designed Synthesis of SiC Nanowire-Derived Carbon With Dual-Scale Nanostructures for Supercapacitor Applications
,”
J. Mater. Chem. A
,
6
(
26
), pp.
12724
12732
.
32.
Haarberg
,
G. M.
,
2018
, “
Challenges for Electrochemical Research in Molten Salts and Ionic Liquids
,”
Electrochemistry
,
86
(
2
), pp.
19
19
.
33.
Yuan
,
Y.
,
Xiao
,
W.
,
Wang
,
Z.
,
Fray
,
D. J.
, and
Jin
,
X.
,
2018
, “
Efficient Nanostructuring of Silicon by Electrochemical Alloying/Dealloying in Molten Salts for Improved Lithium Storage
,”
Angew. Chem., Int. Ed.
,
57
(
48
), pp.
15743
15748
.
34.
Weng
,
W.
, and
Xiao
,
W.
,
2019
, “
Electrodeposited Silicon Nanowires From Silica Dissolved in Molten Salts as a Binder-Free Anode for Lithium-Ion Batteries
,”
ACS Appl. Energy Mater.
,
2
(
1
), pp.
804
813
.
35.
Schwandt
,
C.
, and
Fray
,
D. J.
,
2005
, “
Determination of the Kinetic Pathway in the Electrochemical Reduction of Titanium Dioxide in Molten Calcium Chloride
,”
Electrochim. Acta
,
51
(
1
), pp.
66
76
.
36.
Chen
,
R.
,
Bi
,
J.
,
Wu
,
L.
,
Wang
,
W.
,
Li
,
Z.
, and
Fu
,
X.
,
2009
, “
Template-Free Hydrothermal Synthesis and Photocatalytic Performances of Novel Bi2SiO5 Nanosheets
,”
Inorg. Chem.
,
48
(
19
), pp.
9072
9076
.
37.
Amin
,
I. A.
,
Yarmo
,
M. A.
,
Yusoff
,
N. I. N.
,
Yusoff
,
M. Z.
, and
Ayatillah
,
A.
,
2012
, “
Mesoporous Silica Sol-Gel as Catalyst for the Synthesis of Alkylpolyglucosides
,”
International Conference on X-Ray and Related Technique in Research and Industry (ICXRI 2012)
,
Pulau Pinang, Malaysia
,
July 3–5
, p.
446
.
38.
Boyko
,
A. N.
,
Pyatilova
,
O. V.
,
Kalmykov
,
R. M.
,
Gaev
,
D. S.
,
Timoshenkov
,
S. P.
, and
Gavrilov
,
S. A.
,
2016
, “
Study of Morphological Characteristic of Por-Si Formed Using Metal-Assisted Chemical Etching by BET-Method and Fractal Geometry
,”
International Conference on Micro- and Nano-Electronics
,
Zvenigorod, Russia
,
Oct. 3–7
.
39.
Yu
,
Z.
,
Wang
,
N.
,
Fang
,
S.
,
Qi
,
X.
,
Gao
,
Z.
,
Yang
,
J.
, and
Lu
,
S.
,
2019
, “
Pilot-Plant Production of High-Performance Silicon Nanowires by Molten Salt Electrolysis of Silica
,”
Ind. Eng. Chem. Res.
,
59
(
1
), pp.
1
8
.
40.
Li
,
W.
,
Jin
,
X.
,
Huang
,
F.
, and
Chen
,
G. Z.
,
2010
, “
Metal-to-oxide Molar Volume Ratio: The Overlooked Barrier to Solid-State Electroreduction and a “Green” Bypass Through Recyclable NH4HCO3
,”
Angew. Chem., Int. Ed.
,
49
(
18
), pp.
3203
3206
.
41.
Kubaschewski
,
O.
,
1982
,
Iron-Binary Phase Diagrams
,
Springer
,
Berlin
.
42.
Nash
,
P.
,
1991
,
Phase Diagrams of Binary Nickel Alloys
,
ASM International
,
Materials Park, OH
.
You do not currently have access to this content.