SUPPORTING INFORMATION. A Rechargeable Aluminum-Ion Battery Based on MoS 2. Microsphere Cathode

Transcription

1 SUPPORTING INFORMATION A Rechargeable Aluminum-Ion Battery Based on MoS 2 Microsphere Cathode Zhanyu Li a, Bangbang Niu a, Jian Liu a, Jianling Li a* Feiyu Kang b a School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, No. 30 College Road, Beijing , China. b Shenzhen Key Laboratory for Graphene-based Materials and Engineering Laboratory for Functionalized Carbon Materials, Graduate School at Shenzhen, Tsinghua University, Shenzhen , China * Corresponding author lijianling@ustb.edu.cn (J.Li) S-1

2 1. Experimental section 2.1 Material synthesis All chemicals were of analytical grade and used without further purification. MoS 2 microspheres were synthesized by a simple hydrothermal method g of ammonium heptamolybdate ((NH 4 ) 6 Mo 7 O 24 4H 2 O) used as Mo-source and g of thiourea ((NH 2 ) 2 CS) used as S-source were added to 50 ml of deionized water and stirred for half an hour. The mixtures were transferred into a pressure vessel with 100 ml size autoclave and sealed, and the autoclave was placed in an oven at 200 C for 24 h and naturally cooled down to room temperature. Then the black precipitate was washed three times with deionized water and absolute alcohol, and then the mixture was dried in an oven at 60 C for 12 h. Finally, the black powders were calcined at 450 C in N 2 atmosphere for 6 h to obtain MoS 2 microspheres. 1.2 Battery assembly The as-prepared MoS 2 microspheres and polytetrafluoroethylene (PTFE) binder were ground evenly at a mass ratio of 9:1 for 15 minutes. After that, the mixture was added to 3 ml of organic solvent N-methyl-2-pyrrolidine (NMP) and then sonicated for 2 h to from a homogeneous slurry. The slurry was casted onto a molybdenum (Mo) foil current collector, and then dried at 60 C for 12 h in an oven to obtain the MoS 2 electrodes, which was used as cathode. A room-temperature ionic liquid electrolyte was made by mixing anhydrous aluminum chloride (AlCl 3 ) and 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) at a molar ratio of 1.3:1 in a glove box filled with high purity argon gas. The mixture was then homogeneously stirred and mixed to give a pale yellow ionic liquid, which was used as the rechargeable aluminum batteries electrolyte. The high purity aluminum foil after ethanol cleaning was used as the anode, and a Whatman glass fiber (GF/C) was used as the separator. In addition, the assembly process of the battery is carried out in a glove box. 1.3 Electrochemical tests The galvanostatic charge/discharge performance of the cells were executed in the range of 0.5 V-2.0 V using a Land battery test system (CT2001A Wuhan, China) at S-2

3 different current densities (20 ma g -1, 30 ma g -1 and 40 ma g -1 ) and the cycling tests were conducted at the 40 ma g -1 for 100 cycles. The cyclic voltammetry (CV) tests were performed by VMP2 electrochemical workstation at different scan rates (1 mv s -1, 2 mv s -1, and 5 mv s -1 ) in the voltage range of V(vs. Al). The electrochemical impedance spectroscopy (EIS) measurements were carried out by VMP2 electrochemical system with amplitude of 10.0 mv in the frequency range of 100 khz to 10 mhz. All tests were carried out at room temperature. 1.4 Characterization The detailed morphology and microstructure of the as-prepared MoS 2 microspheres and MoS 2 after electrochemical reactions were determined by field-emission scanning electron microscopy (FESEM, Zeiss SUPRATM 55) and high-resolution transmission electron microscopy (HRTEM, FEI Tecnai F30) with energy dispersive X-ray (EDX) spectroscopy. The electrochemical reaction mechanism of AIBs on the surface and internal of electrode material was studied by X-ray photoelectron spectroscopy (XPS, Shimadzu Kratos Axis Ultra DLD) equipped with an Al anode (Al K=α ev) and Ar ionic sputtering. Prior to all tests, the electrodes subjected to electrochemical performance tests must be washed with anhydrous ethanol three times and dried in a vacuum oven at 60 C for 24 hours in order to avoid the effects of electrolyte and air on the test results. Figure S1 The component analysis of as-prepared MoS 2 microspheres Figure S2 The SEM images of MoS 2 microspheres after 10 cycles. S-3

4 0 s Figure S3 Ex-situ XPS full scan survey of MoS 2 before etching. Mo 3p C 1s Mo 3d Cl 2p S 2p Cl 2s Cu 3s Al 2p Figure S4 Ex-situ XPS full scan survey of MoS 2 after etching 60s. S-4

5 Figure S5 Ex-situ XPS full scan survey of MoS 2 after etching 120s. (a) Mo 3d (b) S 2p (c) Al 2p (d) Mo 3d (e) S 2p (f) Al 2p Figure S6 Ex-situ XPS spectra of MoS 2 : (a) spectra of Mo 3d, (b) spectra of S 2p, (c) S-5

6 spectra of Al 2p after Ar + sputtering for 60s; (d) spectra of Mo 3d, (e) spectra of S 2p, (f) spectra of Al 2p after Ar + sputtering for 120s. Intensity(a.u.) discharge 0.5V θ/degree Figure S7 Ex-situ X-ray diffraction pattern of MoS2 electrode. Table S1 Performance comparison between our work and papers Number Cathode First discharge capacity Discharge voltage References 1 MoS ma h g V This work 2 Li 3 VO 137 ma h g V 1 3 CuHCF 60 ma h g V 2 4 CuS@C ma h g V 3 5 Cu 0.31 Ti 2 S 4 80 ma h g V 4 6 SnS ma h g V 5 References [1] Jiang, J. L.; Li, H.; Huang, J. X.; Li, K.; Zeng, J.; Yang, Y.; Li, J. Q.; Wang, Y. H.; Wang, J. Investigation of the Reversible Intercalation/Deintercalation of Al into the Novel Li 3 VO Microsphere Composite Cathode Material for Aluminum-Ion Batteries. ACS Appl. Mater. Interfaces 2017, 9, [2] Reed, L. D.; Ortiz, S. N.; Xiong, M.; Menke, E. J. A Rechargeable Aluminum-Ion Battery Utilizing a Copper Hexacyanoferrate Cathode in an Organic Electrolyte. Chem. Commun., 2015, 51, [3] Wang, S.; Jiao, S.; Wang, J.; Chen, H. S.; Tian, D.; Lei, H.; Fang, D. N. High-Performance Aluminum-Ion Battery with CuS@C Microsphere Composite Cathode. ACS Nano 2017, 11, [4] Geng, L. X.; Scheifers, J. P.; Fu, C. Y.; Zhang, J.; Fokwa, B. P. T.; Guo, J. C. Titanium Sulfides as Intercalation-Type Cathode Materials for Rechargeable Aluminum Batteries. ACS Appl. Mater. Interfaces 2017, 9, [5] Hu Y. X., Luo B., Ye D. L., Zhu X. B., Lyu M. Q., Wang L. Z. An Innovative S-6

7 Freeze-Dried Reduced Graphene Oxide Supported SnS 2 Cathode Active Material for Aluminum-Ion Batteries Adv. Mater. 2017, 29, S-6