Supporting Information. Controlled-Synthesis of Copper Telluride Nanostructures for Long-cycling Anodes in Lithium Ion Batteries

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1 Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A. This journal is The Royal Society of Chemistry 2014 Supporting Information Controlled-Synthesis of Copper Telluride Nanostructures for Long-cycling Anodes in Lithium Ion Batteries Chao Han, Zhen Li*, Wei-jie Li, Shu-lei Chou, Shi-xue Dou Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, Squires Way, North Wollongong, NSW 2500, Australia. *To whom correspondence should be addressed. Contents 1. Figures... 3 Figure S1. XPS spectra of Te 3d from copper telluride nanocubes and copper telluride nanosheets Figure S2 SEM images and size distributions of copper telluride nanocubes prepared from different reaction times: (a, d) 5min, (b, e) 6min, and (c, f) 8min Figure S3 SEM images and size distribution of nanostructures prepared using different CuCl concentrations at 250 : (a, d) 0.2 M, (b, e) 0.05 M, and (c, f) 0.01M Figure S4 (a b) SEM images of samples prepared at 230 and 270 using 0.02 M CuCl; (c) size distribution of sample prepared at 230 ; (d) XRD pattern of sample prepared at Figure S5 SEM image, size distribution and (c) X ray diffraction pattern of copper telluride nanocubes synthesised with a ratio of (CuCl/TOPTe) Figure S6 XRD patterns of samples prepared in oleic acid, TOPO and oleylamine Figure S7 SEM images and XRD patterns of nanocubes prepared by adding small amount of ligands into TOP: oleylamine; TOPO; (c) oleic acid Figure S8 XRD and SEM images of samples prepared with different copper precursors. XRD patterns; CuBr; (c) CuCl 2 ; (d) CuF 2 ; (e) Cu(CH 3 COO) 2 ; (f) Cu(acac) 2. All scale bars are 200 nm Figure S9 XRD and SEM image of precipitate obtained by heating CuF 2 in TOP at 250 for min

2 Figure S XRD and SEM image of product obtained by heating CuCl in oleylamine at 250 for min Figure S11 Different Cu 2 x Te sheet structure synthesised under different temperatures and CuCl concentrations. TEM of sample synthesised with 0.02 M CuCl at 230 ; sample obtained from 0.02 M CuCl at 270 ; (c) sample synthesised with 0.05 M CuCl at 250 ; (d) sample synthesised with M CuCl at Figure S12 Ex situ XRD for Cu2 xte electrodes stopped at different voltage plateaus: voltage state of the plateaus; ex situ XRD for the 4 electrodes Synthesis of hollowed Cu 2 x Te nanoparticles

3 1. Figures Te 3d 3/ ev Te 3d 5/ ev Cu LMM Oxidized layer Binding Energy (ev) Te 3d 3/2 Te 3d 5/ ev Cu LMM Binding Energy(eV) Figure S1. XPS spectra of Te 3d from copper telluride nanocubes and copper telluride nanosheets. 3

4 (d) Frequency(%) D= nm (e) Size(nm) 30 D= nm Frequency(%) 20 (c) (f) Size(nm) 30 D= nm Frequency(%) Size(nm) Figure S2 SEM images and size distributions of copper telluride nanocubes prepared from different reaction times: (a, d) 5min, (b, e) 6min, and (c, f) 8min. 4

5 (c) (d) 30 D= nm Frequency(%) 20 (e) Size/nm 30 D= nm Frequency(%) 20 (c) (f) Size(nm) 20 D=60.7±9.1nm Frequency(%) Size(nm) Figure S3 SEM images and size distribution of nanostructures prepared using different CuCl concentrations at 250 : (a, d) 0.2 M, (b, e) 0.05 M, and (c, f) 0.01M. 5

6 (c) Frequency(%) D= nm (d) Cu 2-x Te Size(nm) /Degree Figure S4 (a b) SEM images of samples prepared at 230 and 270 using 0.02 M CuCl; (c) size distribution of sample prepared at 230 ; (d) XRD pattern of sample prepared at

7 D= nm Frequency(%) 20 (c) Size(nm) /Degree Figure S5 SEM image, size distribution and (c) X ray diffraction pattern of copper telluride nanocubes synthesised with a ratio of (CuCl/TOPTe). 7

8 (201) (6) (301) (0) (1) (207) (1,0,) (2) (1) (201) Pure Oleic Acid Cu 4 Te 3 Cu 1.85 Te (209) (321) (208) (409) Pure TOPO (2) Te CuTe (200) (6) (2) (119) Pure Oleylamine Cu 2-x Te (209) (401) (1,1,14) /Degree Figure S6 XRD patterns of samples prepared in oleic acid, TOPO and oleylamine. 8

9 (c) (d) TOPO Oleic Acid Oleylamine /Degree Figure S7 SEM images and XRD patterns of nanocubes prepared by adding small amount of ligands into TOP: oleylamine; TOPO; (c) oleic acid. 9

10 Cu 2-x Te Cu 7 Te 5 CuBr CuF 2 Cu 2.72 Te 2 CuCl 2 Cu(acac) 2 Cu(ac) /Degree (c)

11 (d) (e) (f) Figure S8 XRD and SEM images of samples prepared with different copper precursors. XRD patterns; CuBr; (c) CuCl 2 ; (d) CuF 2 ; (e) Cu(CH 3 COO) 2 ; (f) Cu(acac) 2. All scale bars are 200 nm. 11

12 (111) Cu (200) (220) /Degree Figure S9 XRD and SEM image of precipitate obtained by heating CuF 2 in TOP at 250 for min. 12

13 (111) Cu (200) (220) /Degree Figure S XRD and SEM image of product obtained by heating CuCl in oleylamine at 250 for min. 13

14 Figur e S (c) (d) Figure S11 Different Cu 2 x Te sheet structure synthesised under different temperatures and CuCl concentrations. TEM of sample synthesised with 0.02 M CuCl at 230 ; sample obtained from 0.02 M CuCl at 270 ; (c) sample synthesised with 0.05 M CuCl at 250 ; (d) sample synthesised with M CuCl at

15 Figure S12 Ex situ XRD for Cu2 xte electrodes stopped at different voltage plateaus: voltage state of the plateaus; ex situ XRD for the 4 electrodes. 15

16 2. Synthesis of hollowed Cu 2 x Te nanoparticles. In order to investigate the effect of materials shapes on battery performance, hollowed Cu 2 x Te nanoparticles were synthesised as followed: Cu(acac) 2 (0.25 mmol), HDA (4.18 g), and TOP (2 ml) were loaded into a 0 ml three neck flask. After being degassed at 0 for 30 min, the mixture was heated to 250 under protection of Ar and a yellow copper precursor solution formed. The solution was kept at 250 for min to let the temperature stable and the solution changed into brown, 125 µl, 1 M TOPTe solution was swiftly injected into the copper precursor. The temperature of the copper precursor decreased no more than 1 and was kept at 250 for another min, the solution turned into black. The product was purified by repeatedly precipitating and re dispersing in ethanol and dichloromethane, respectively. 16