S1
Supporting Information
Amorphous Cobalt Selenite Nanoparticles D
ecorated on Graphitic Carbon Hollow Shell
for High-Rate and Ultralong Cycle Life Lith
ium-Ion Batteries
Gi Dae Park and Yun Chan Kang*
Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713, Republic of Korea
*Corresponding author
E-mail: [email protected]. Tel.: +82-2-928-3584. Fax: +82-2-3290-3268.
This file includes:
Number of pages: 19 Number of tables: 1 Number of figures: 12
Information of characterization and electrochemical measurements. (Page S3-S4)
Figure S1. Morphologies of hollow carbon nanospheres and cobalt acetylacetonate and selenium infiltrated hollow carbon nanospheres. (Page S5)
S2
Figure S2. XRD patterns of CoSe2-Se-C, CoSeOx-C, and Co3O4 hollow nanospheres.
(Page S6)
Figure S3. SEM images of CoSe2-Se-C nanospheres. (Page S7)
Figure S4. Raman spectrum of CoSeOx-C hollow nanospheres. (Page S8)
Figure S5. TG curve of CoSeOx-C hollow nanospheres. (Page S9)
Figure S6. Morphologies, SAED pattern, and elemental mapping images of Co3O4
hollow nanospheres. (Page S10)
Figure S7. N2 gas adsorption and desorption isotherms and pore size distributions of CoSeO3-C, and Co3O4 hollow nanospheres. (Page S11)
Figure S8. Morphologies of CoSeOx-C measured at the first fully charged state and CoSeOx-C measured after 1000 cycles. (Page S12)
Figure S9. SEM images of CoSeOx-C nanospheres oxidized at 350 oC and CoSeOx
nanospheres oxidized at 380 oC. (Page S13)
Figure S10. XRD pattern, the initial discharge and charge profile, cycle performance, and c-rate performance of CoSeOx nanospheres oxidized at 380 oC. (Page S14)
Figure S11. Electrochemical performances of hollow carbon nanospheres: initial discharge and charge curves, cycling performance, rate performance, GITT potential profiles, Li-ion diffusion coefficient during lithiation step, and Li-ion diffusion coefficient during delithiation step. (Page S15)
Figure S12. Equivalent circuit model used for ac impedance fitting. (Page S16)
Table S1. Electrochemical properties of various cobalt-based TMCs (cobalt oxide, cobalt selenide, and cobalt selenite hydrate) applied as lithium-ion batteries reported in the previous literatures. (Page S17-19)
S3 Characterizations
The morphological characteristics of the samples were investigated via scanning electron microscopy (SEM, VEGA3) and field emission-transmission electron microscopy (FE-TEM, JEM-2100F). The crystal structures of the samples were analyzed using X-ray diffraction spectroscopy (XRD, X’Pert PRO with Cu Kα radiation, λ = 1.5418 Å) at the Korea Basic Science Institute (Daegu). X-ray photoelectron spectroscopy (XPS) of the samples was performed using ESCALAB-250 with Al Kα
radiation (1486.6 eV). Ex-situ XPS analysis of sample at the first fully discharged and charged states was also performed with the aforementioned measuring equipment. To prepare electrode for ex-situ analysis, the 2032-type coin cells, which were fully discharged to 0.001 V and charged to 3.0 V, were disassembled in glove box to minimize exposure to air. Thermogravimetric (TG) analysis (Pyris 1 Thermogravimetric Analyzer, PerkinElmer) was conducted in the range 25–800 °C at 10 °C min−1 under an air atmosphere. The surface area and porosities of the samples were analyzed via Brunauer–Emmett–Teller (BET) method, using high-purity N2. The structural characteristics of carbon in the sample were investigated via Raman spectroscopy (Jobin Yvon LabRam HR800, excited by a 632.8-nm He/Ne laser) at room temperature.
Electrochemical measurements
To measure the electrochemical properties of the samples, a 2032-type coin cell constructed from electrodes prepared via the slurry process was utilized. For the anode electrode, the active materials, carbon black (Super-P), and sodium carboxymethyl cellulose (CMC) in a weight ratio of 7:2:1 were uniformly mixed with water solvent in a mortar. The well-mixed slurry was coated onto Cu foil using a doctor blade and dried in
S4
a vacuum oven for 3 h. Lithium metal and a microporous polypropylene film were used as the counter electrode and separator, respectively. The electrolyte was 1 M LiPF6
dissolved in a mixture of fluoroethylene carbonate and dimethyl carbonate (FEC/DMC;
1:1 v/v). The diameter and mass loading of the negative electrode were 14 mm and 1.4 mg cm−2, respectively. The discharge–charge characteristics of the samples were analyzed via cycling in 0.001–3.0 V potential range at various current densities. Cyclic voltammetry (CV) analysis was conducted at a scan rate of 0.1 mV s-1. The specific capacity of CoSeOx-C for lithium-ion batteries is based on the total active materials mass (CoSeOx-C). Electrochemical impedance spectroscopy (EIS, ZIVE SP1) measurements of the electrode were performed over a frequency range of 0.01 Hz – 100 kHz. In-situ EIS analysis was performed at preselected potentials during the discharge and charge process at a current density of 0.1 A g−1.
S5
Figure S1. Morphologies of hollow carbon nanospheres and cobalt acetylacetonate and selenium infiltrated hollow carbon nanospheres : (a,b) hollow nanospheres and (c,d) cobalt acetylacetonate and selenium infiltrated hollow carbon nanospheres.
S6
Figure S2. XRD patterns of CoSe2-Se-C, CoSeOx-C, and Co3O4 hollow nanospheres.
S7
Figure S3. (a-c) SEM images of CoSe2-Se-C nanospheres.
S8
Figure S4. Raman spectrum of CoSeOx-C hollow nanospheres.
S9
Figure S5. TG curve of CoSeOx-C hollow nanospheres.
S10
Figure S6. Morphologies, SAED pattern, and elemental mapping images of Co3O4
hollow nanospheres: (a-c) TEM images, (d) HR-TEM image, (e) SAED pattern, and (f) elemental mapping images.
S11
Figure S7. (a) N2 gas adsorption and desorption isotherms and (b) pore size distributions of CoSeOx-C, and Co3O4 hollow nanospheres.
S12
Figure S8. Morphologies of (a,b) CoSeOx-C measured at the first fully charged state and (c,d) CoSeOx-C measured after 1000 cycles: (a,b) TEM images (c,d) SEM images.
S13
Figure S9. SEM images of (a) CoSeOx-C nanospheres oxidized at 350 oC and (b) CoSeOx nanospheres oxidized at 380 oC.
S14
Figure S10. (a) XRD pattern, (b) the initial discharge and charge profile, (c) cycle performance, and (d) c-rate performance of CoSeOx nanospheres oxidized at 380 oC.
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Figure S11. Electrochemical performances of hollow carbon nanospheres: (a) initial discharge and charge curves, (b) cycling performance, (c) rate performance, (d) GITT potential profiles, (e) Li-ion diffusion coefficient during lithiation step, and (f) Li-ion diffusion coefficient during delithiation step.
S16
Re : the electrolyte resistance, corresponding to the intercept of high frequency semicircle at Zre axis
Rf : the SEI layer resistance corresponding to the high-frequency semicircle
Q1 : the dielectric relaxation capacitance corresponding to the high-frequency semicircle Rct: the denote the charger transfer resistance related to the middle-frequency semicircle Q2 : the associated double-layer capacitance related to the middle-frequency semicircle Zw : the Li-ion diffusion resistance
Figure S12. Equivalent circuit model used for ac impedance fitting.
S17
Table S1. Electrochemical properties of various cobalt-based TMCs (cobalt oxide, cobalt selenide, and cobalt selenite hydrate) applied as lithium-ion batteries reported in the previous literatures.
Materials
Potential range
[V]
Current rate [A g-1]
Discharge capacity [mA h g-1] and (cycle number)
Rate capacity [mA h g-1]
(current rate) [ A g-1]
Ref
Mesoporous Co3O4
nanowire arrays 0.01-3.0 0.078 700 (20) 450
(15.6) [S1]
Co3O4 nanosheet- assembled multishelled hollow spheres
0.01-3.0 0.45 866 (50) 500
(1.78) [S2]
Hollow-structured Co3O4
nanoparticles
0.05-3.0 0.45 880 (50) 450
(2.0) [S3]
Micro- /nanostructured
Co3O4 cubes
0.01-3.0 0.89 980 (60) 130
(8.9) [S4]
Mesoporous Co3O4
nanoflakes 0.01-3.0 0.89 883 (300) 285
(8.9) [S5]
Mesoporous single-crystalline
Co3O4 nanobelts
0-3.0 1.0 980 (60) 605
(3.0) [S6]
Co3O4 nanocages 0.05-3.0 0.05 854 (30) 252
(2.0) [S7]
CoSe nanoparticles embedded within
porous carbon polyhedra
0.005-3.0 0.2 657 (200) 198.6
(5.0) [S8]
Layered Co0.85Se 0.01-3.0 0.2 516 (50) 374 [S9]
S18
nanosheets (2.0)
CoSeO3∙H2O/graph
ene nanosheets 0.01-3.0 3.0 1100 (1000)
1530
(2.0) [S10]
Anhydrous CoSeO3
microspheres
0.001-3.0 3.0 709 (1400) 526
(30.0) [S11]
Amorphous CoSeOx-C hollow
nanospheres
0.001-3.0 5.0 799 (3000) 691 (30)
This work
References
(S1) Li, Y.; Tan, B.; Wu, Y., Mesoporous Co3O4 nanowire arrays for lithium ion batteries with high capacity and rate capability, Nano Lett. 2008, 8, 265-270.
(S2) Wang, X.; Wu, X.-L.; Guo, Y.-G.; Zhong, Y.; Cao, X.; Ma, Y.; Yao, J., Synthesis and lithium storage properties of Co3O4 nanosheet‐assembled multishelled hollow spheres, Adv. Funct. Mater. 2010, 20, 1680-1686.
(S3) Wang, D.; Yu, Y.; He, H.; Wang, J.; Zhou, W.; Abruna, H. D., Template-free synthesis of hollow-structured Co3O4 nanoparticles as high-performance anodes for lithium-ion batteries, ACS Nano 2015, 9, 1775-1781.
(S4) Huang, G.; Xu, S.; Lu, S.; Li, L.; Sun, H., Micro-/nanostructured Co3O4 anode with enhanced rate capability for lithium-ion batteries, ACS Appl. Mater. Interfaces 2014, 6, 7236-7243.
(S5) Chen, S.; Zhao, Y.; Sun, B.; Ao, Z.; Xie, X.; Wei, Y.; Wang, G., Microwave- assisted synthesis of mesoporous Co3O4 nanoflakes for applications in lithium ion batteries and oxygen evolution reactions, ACS Appl. Mater. Interfaces 2015, 7, 3306- 3313.
(S6) Huang, H.; Zhu, W.; Tao, X.; Xia, Y.; Yu, Z.; Fang, J.; Gan, Y.; Zhang, W., Nanocrystal-constructed mesoporous single-crystalline Co3O4 nanobelts with superior rate capability for advanced lithium-ion batteries, ACS Appl. Mater. Interfaces 2012, 4 5974-5980.
(S7) Yan, N.; Hu, L.; Li, Y.; Wang, Y.; Zhong, H.; Hu, X.; Kong, X.; Chen, Q., Co3O4
nanocages for high-performance anode material in lithium-ion batteries, J. Phys. Chem.
C 2012, 116, 7227-7235.
(S8) Li, J.; Yan, D.; Lu, T.; Yao, Y.; Pan, L., An advanced CoSe embedded within porous carbon polyhedra hybrid for high performance lithium-ion and sodium-ion
S19 batteries, Chem. Eng. J. 2017, 325, 14-24.
(S9) Zhou, J.; Wang, Y.; Zhang, J.; Chen, T.; Song, H.; Yang, H. Y., Two dimensional layered Co0.85Se nanosheets as a high-capacity anode for lithium-ion batteries, Nanoscale 2016, 8, 14992-15000.
(S10) Jiang, Y.; Song, Y.; Pan, Z.; Meng, Y.; Jiang, L.; Wu, Z.; Yang, P.; Gu, Q.; Sun, D.; Hu, L., Rapid amorphization in metastable CoSeO3·H2O nanosheets for ultrafast lithiation kinetics, ACS Nano 2018, 12, 5011-5020.
(S11) G. D. Park, J. H. Hong, J. H. Choi, J.-H. Lee, Y. S. Kim. Y. C. Kang, Synthesis process of CoSeO3 microspheres for unordinary Li‐ion storage performances and mechanism of their conversion reaction with Li ions, Small 2019, 15, 1901320.
