SUPPORTING INFORMATION. High-Voltage and Noncorrosive Ionic Liquid Electrolyte Used in Rechargeable Aluminum Battery

Transcription

1 SUPPORTING INFORMATION High-Voltage and Noncorrosive Ionic Liquid Electrolyte Used in Rechargeable Aluminum Battery Huali Wang, Sichen Gu, Ying Bai,, ** Shi Chen, Feng Wu,, and Chuan Wu,, ** Beijing Key Laboratory of Environmental Science and Engineering, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing , China Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing , China ** Corresponding Authors: (Ying Bai) (Chuan Wu) S-1

2 Experiment Details: The reagents were obtained from commercial sources and used without further purification. [BMIM]OTF (99%) was bought from Shanghai Jie Cheng Chemical Co., Ltd. The Al(OTF) 3 was bought from Alfa Aesar. The preparation of Al(OTF) 3 /[BMIM]OTF ionic liquid was performed in a glove box filled with inert gas Ar. Al(OTF) 3 was added to the [BMIM]OTF ionic liquid under stirring at a series molar concentration (0, 0.05, 0.1, 0.5, 1mol/L). Infrared spectra of ionic liquids were obtained with a Nicolet is10 Fourier Transform Infrared Spectroscopy (FTIR) spectrometer at 4 cm -1 resolution. Cyclic Voltammetry (CV) and ionic conductivity were both measured on CHI604D electrochemical workstation. In CV measurement, the glassy carbon (GC) disk electrode (diameter 2mm) was used as working electrode, Al metal was used as the counter electrode and reference electrode, and the scan rate is 10mV/s. In ionic conductivity test, a DJS-1 type conductivity electrode was used. V 2 O 5 nanowire was synthesized similar to the method used previously g V 2 O 5 and 5 ml 30wt% H 2 O 2 were added to 30 ml water and magnetically stirred for 0.5h. Then, the prepared solution was transferred to a polytetrafluoroethene-lined stainless steel reactor and heated for four days at 205 ºC. Finally, the prepared product was taken out and washing with deionized water for several times. After 60 ºC vacuum drying for 24h, it is calcinated at 500 ºC for 4 hours in air to get the final product. Rechargeable aluminum battery (2025 coin-type cells) using Al(OTF) 3 / [BMIM]OTF ionic liquid as electrolyte was assembled in an argon-filled glove box. The cathode was made with V 2 O 5 nanowire: Super P: PTFE binder=8:1:1 (mass ratio) coated on Al foam. Whatman glass S-2

3 fiber (GF/C) was selected as the separator, and Al metal foil ( % Al purity) was used as the anode. Al anode is treated by immersing in AlCl 3 /[BMIM]Cl=1.1:1 ionic liquids for 24 hours, then it was taken out, washed with ethanol and dry. All Al treatment procedures are performed in glove box. AlCl 3 /[BMIM]Cl=1.1:1 ionic liquid was prepared by mixing AlCl 3 with [BMIM]Cl according to molar ratio, then stirred overnight until homogeneous and clear liquid obtained. Galvanostatic charge discharge test was performed on a LAND CT2001A battery tester in a potential range of V, at the current density of 10 ma/g. S-3

4 Table S1. Frequencies and assignments of vibrations in Figure 1 [BMIM]OTF 0.05 mol/l 0.1 mol/l 0.5 mol/l 1 mol/l C 4,5 -H stretching C 2 -H stretching CH 3 asymmetric stretching CH 2 asymmetric stretching CH 3 symmetric stretching C=N stretching CH 3 asymmetric bending CH 2 in-plane bending CH 3 symmetric bending SO 3 asymmetric stretching SO 3 symmetric stretching CF 3 asymmetric stretching SO 3 symmetric stretching C N deformation CF 3 asymmetric bending SO 3 symmetric bending C-H out-plane deformation CF 3 symmetric bending SO 3 asymmetric bending S-4

5 -Z"/ohm Efficiency /% Table S2 Ea calculated from Arrhenius and Vogel-Tamman-Fulcher (VTF) plot 1mol/L 0.5mol/L 0.1mol/L 0.05mol/L [BMIM]OTF Ea calculated from Arrhenius plot 34 kj 33 kj 31 kj 28 kj 30 kj Ea calculated from VTF plot 622 K 573 K 534 K 492 K 523 K mol/L 0.5mol/L 1mol/L Cycle number Figure S1 Coulombic efficiency of rechargeable aluminum batteries with using Al(OTF) 3 /[BMIM]OTF ionic liquids. 1.6x10 5 Before cycle After 5th cycle 1.2x x x x x x x10 5 Z'/ohm Figure S2 Electrochemical Impedance Spectra (EIS) of rechargeable aluminum battery with 0.5 mol/l Al(OTF) 3 /[BMIM]OTF ionic liquid electrolyte before and after cycles S-5

6 0.4 Capacity /mah g -1 Voltage /V (a) (b) st 2nd 3rd Cycle number Capacity /mah g -1 Figure S3 (a) Cycling performance; (b) Charge/discharge profiles of rechargeable aluminum battery using 0.5M Al(OTF) 3 /[BMIM]OTF ionic liquid electrolyte and untreated Al anode S-6