An Anode Material Associated with Polymeric Networking of Triflate Ions Formed on Mg

Transcription

1 Supporting information: n node Material ssociated with Polymeric Networking of Triflate Ions Formed on Mg Tohru Shiga,* Yuichi Kato, Masae Inoue, Naoko Takahashi, and Yoko Hase Toyota entral Research & Development Laboratories Inc. 1. Experimental section 1.1 Materials (a) MImdzF4 (b)pp1tfs (c) PTM + FSO - SI Figure 1 hemical structure of materials 1.2 ells + node R.E athode Pt Φ14mm Electrolyte Separators Mg arbon /PTM + F SO - - Mg Φ1mm 0.1mol/LMg(F SO ) 2 -PP1TFS (a) oin cell SI Figure 2 Schematic illustrations of test cells. (b) Three-electrode test cell

2 2. Results & Discussion 2.1 Raman data Raman spectra of research reagents, Mg(FSO)2 and PP1TFS were shown in SI Figure a. SI Fig.b showed Raman data for the specimens,, and (at points in Figure 1) in the range of 2500 cm -1 to 500 cm -1. Intensity (a.u.) Mg(F SO ) PP1TFS Raman shift (cm ) (a) Mg(FSO)2 and PP1TFS 440 Intensity (a.u.) Raman shift (cm ) (b) Specimens,, and ( cm -1 ) SI Figure Raman spectra

3 2.2 SIMS data SI Figure 4 shows TOF-SOMS spectra of negative ions for Pt electrodes before and after charging, and after charging, respectively. It was found that the signal due to FSO - at m/z= 149 was weakened by discharging, and then enhanced after charging. Intensity (counts) Intensity (counts) F SO 2 N - F SO SI Figure 4 TOF-SIMS spectra of negative ions for Pt plates *The three SIMS data for the specimens,, and were described in turn from upper to bottom. SI Figure 5 shows TOF-SOMS spectra of positive ions from Mg anodes before and after charging, and after charging, respectively. The signal at m/z= 24 (red circle) is due to magnesium. The intensity of the signal is off the scale. The signal at m/z=142 due to 9H20N + is very weak, suggesting that the interaction between Mg and PP1 + was small.

4 Intensity (counts) Intensity (counts) H 20 N SI Figure 5 TOF-SIMS spectra of positive ions for Mg plates *The three SIMS data for the specimens,, and were described in turn from upper to bottom. 2. LiF SO -H N adduct SI Figure hemical structure of LiFSO-HN adduct quoted from Ref. 2

5 2.4 Measurement of discharge capacity due to polymeric networking s mentioned in the text, the discharge behavior for the 0.1mol/L Mg(FSO)2- PP1TFS system was associated with FSO anions. In order to understand the effect of the amount of FSO anion the discharge capacities of 0.1mol/L Mg(FSO)2- PP1TFS systems were measured by changing separation between Mg and Pt. We defined the discharge capacity up to 0V as the capacity of the polymeric networking. The relation between cell voltage and discharge capacity were displayed in SI Figure 7. s the electrode separation was enlarged, the discharge capacity was increased. The result suggests that the discharge behavior depends on the amount of FSO - in the electrolyte. It has been roughly estimated that a quarter of FSO anion in the electrolyte were involved with the networking behavior (SI Table I). The charging curves were also plotted in SI Figure 7. The charge capacity depended on the electrolyte volume as well. ell voltage(v) / harge Separation = 5mm Paper separator Separation = 2mm Discharge capacity(mh) SI Figure 7 Discharge curves of cells using various electrode separations. The thickness of paper separator was 0.2mm.

6 SI Table I Estimation of capacity of polymeric networking ell No. Separation Electrolyte a apacity of F SO b Experimental c (mm) (cc) (mh) (mh) (a) volume of electrolyte between electrodes, (b) discharge capacity estimated from the concentration of FSO in the electrolyte, (c) discharge capacity up to 0V. 2.5 apacity fading The capacity fading was observed during the discharge/charge cycles (Figure 9a in the text). In order to investigate the stability of PTM as an active material we measured capability of PTM tested for 10 cycles. The tested cathode was washed with acetonitrile several times prior to acquiring these images. We set up a cell using the washed cathode, and Li anode, an electrolyte of 1 mol/l LilO4-EDE, and operated voltage between.1v and.9v(si Figure 8). s the theoretical capacity of PTM was 110mh/g, it was found that the degradation of PTM occurred. ell voltage(v) apacity(mh/g) SI Figure 8 harge-discharge curves of a battery using Li anode and the PTM + FSO - cathode after the tested at 0. *1 st cycle (black), 2 nd cycle (pink), and rd cycle (orange) * The electrolyte used was 1 mol/l LilO4/E+DE.

7 2. Photographs of Mg electrode SI Figure 9 shows photographs of Mg electrode analyzed by Raman and XPS measurements. The Mg electrode before discharge, but annealed, had metallic luster. On the other hand, the Mg electrode after 1 st discharge was covered with blackish film. The grayish film was observed in the sample after 1 st recharge. (a) before discharge (b) after 1 st discharge (c) after 1 st recharge SI Figure 9 Photographs of Mg electrode (Diameter of Mg electrode = 18 mm)