Supplementary Information

Scalable Production of 3D Plum-Pudding-Like Si/C Spheres:

Towards Practical Application Design in Li-Ion Batteries

Guolin Hou†,‡, Benli Cheng§, Yuebin Cao†, Mingshui Yao, Baoqiang Li†,‡, Chao

Zhang&, Qunhong Weng&, Xi Wang#, *, Yoshio Bando&, Dmitri Golberg& and Fangli

Yuan†,*

†State Key Laboratory of Multi-phase Complex Systems, Institute of Process

Engineering, Chinese Academy of Sciences (CAS), Zhongguancun Beiertiao 1 Hao,

Beijing 100190, P. R. China

‡ University of Chinese Academy of Sciences (UCAS), No.19A Yuquan Road, Beijing

100049, P. R. China

§ Green Eco-Manufacture Co., Ltd. Tianjin Branch, Tianjin, 301600, P. R. China

State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the

Structure of Matter, Chinese Academy of Sciences (CAS), 155 Yangqiao Road west,

Fuzhou, 350002, P. R. China

&World Premier International Center for Materials Nanoarchitectonics (WPI-MANA),

National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-

0044, Japan.

# School of Sciences, Beijing Jiaotong University, Beijing, 100044, P. R. China

*Corresponding author.

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E-mail: flyuan@home.ipe.ac.cn. Fax: +86-10-62561822. Tel: +86-10-82544974.E-mail: wangxicas@gmail.com or xiwang@bjtu.edu.cn.

Fig. S1. Schematic illustration of the RF induction thermal plasma processing system setup and the photograph of plasma torch.

A schematic of the plasma jet reactor is shown in Fig S1. The experimental setup

consists of a RF generator (10 kW, 4 MHz), a swirl-stabilized plasma torch, a

cylindrical reactor, a quench/collection vessel, a particle feeder system, and an off-gas

exhaust system. The plasma torch consists of a quarts tube (to confine thermal

plasma) and a water-cooled induction coil to couple its electromagnetic energy to

thermal plasma. Argon (Ar, 99.9%) was used as the plasma gas and the quenching

gas. When the RF thermal plasma was running, the central gas was injected

continuously to stabilize the plasma jet, and the sheath gas was used to protect the

quartz tube from the high temperature during discharge.

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Fig. S2. (a) Schematic diagram of the spray drying synthesis of 3D SiNS/C composite

materials and (b) the photograph of a spray dryer.

The process starts with atomization of the precursors’ solution into a spray of

microdroplets using a two-fluid nozzle (Fig. S2a). This step is accomplished by

simultaneously injecting the solution at a certain rate (feed rate) and compressed air at

another rate (flow rate). Thus, each precursor droplet is in contact and is suspended by

a gas stream heated to a certain temperature (inlet temperature), causing the solvent to

begin evaporating. In a typical experiment, homogeneously dispersed suspension was

spray dried using a spray drying machine at a certain feed rate, with a certain flow

rate of compressed air and the certain inlet temperature. Once the precursor solution

was atomized, a dry brown powder instantly formed in the spray dryer collector (Fig.

S2b).

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Fig. S3. Zeta potential of the starting material made of Si nanospheres in aqueous

solution.

Fig. S4. (a)-(b) FESEM image, (c) particle size distribution, (d) the EDX spectrum

and (e-f) elemental mapping (Si: yellow; C: red) of as-prepared SiNS/G composites.

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Fig. S5. N2 adsorption-desorption isotherms of the SiNS/C (a) and SiNS/G (b)

composite; the inset is the corresponding BJH pore size distribution.

Fig. S6 TG curves under air atmosphere at the heating rate of 10C min-1of Si/C composites

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Fig. S7. Typical lattice-resolved HRTEM image of the graphitized carbon.

Fig. S8 Cross-sectional SEM images of Si/C electrode before (a) and after cycling (b).

Fig. S9. TEM image of pure Si nanospheres after cycling, indicating that severe

agglomeration happens.

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Table S1. The initial coulombic efficiency (ICE) of Si/C hybrid anodes prepared by using the different carbon precursors.

Carbon Precursor Method ICESucrose Spray-pyrolysis 83.5%1

PVC Solution/annealing 66.2%2

Glucose Solution/annealing ∼55%3

Toluene CVD ∼72%4

Citric acid Spray-pyrolysis 71.4%5

Graphite CVD 71.6%6

Maltose Solution/annealing 70%7

PDA Electrostatic pinning/annealing 73.8%8

PAN Solution/annealing ∼63%9

Pitch Solution/annealing 75.6%10

Graphene nanosheets Self-assembly 83.5%11

CH4 CVD 83%12

Polymer Microemulsion/annealing 82%13

Glucose RF-plasma/spray drying 88% (this work)

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Table S2. The initial coulombic efficiency (ICE) of Si and Si/C hybrid anodes using different binders.

Binders Si and Si/C products ICEPVDF nano-Si/C 70%14

PAA Micro-Si/C 77%15

PAA-PVA 100 nm-Si 83.9%16

PAA-C ∼50 nm Si 71.2%17

PI 5 μm-Si 81%18

Self-healing polymers ∼3–8 μm-Si 80%19

PFFOMB 10–50 nm Si 56%20

Alg-C ∼50 nm Si 60.1%17

CMC 44 μm-Si ∼80%21

Li-polyacrylic acid ~ 100nm Si/graphene 83%12

PVDF 500 nm-10 m micro-Si/C spheres consisting of ~80 nano-sized spheres

82%13

CMC 2-5m micro-Si/C spheres consisting of ~50 nano-sized spheres

88% (this work)

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