Supporting Information

Transcription

1 Copyright WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany, Supporting Information for Adv. Funct. Mater., DOI: /adfm Discovering a Dual-Buffer Effect for Lithium Storage: Durable Nanostructured Ordered Mesoporous Co Sn Intermetallic Electrodes Gwi Ok Park, Jeongbae Yoon, Jeong Kuk Shon, Yun Seok Choi, Jong Gu Won, Su Bin Park, Kyoung Ho Kim, Hansu Kim,* Won-Sub Yoon,* and Ji Man Kim*

2 Copyright WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany, Supporting Information Discovery of Dual-Buffer Effect on Lithium Storage: Durable Nanostructure of Ordered Mesoporous Co-Sn Intermetallic Electrode Gwi Ok Park, Jeongbae Yoon, Jeong Kuk Shon, Yun Seok Choi, Jong Gu Won, Su Bin Park, Kyoung Ho Kim, Hansu Kim*, Won-Sub Yoon*, and Ji Man Kim* Figure S1. a) Low angle XRD pattern, b) Wide angle XRD pattern, c) N 2 sorption isotherms and corresponding pore size distribution (inset), and d) TEM image of mesoporous silica KIT- 6 template. 1

3 Figure S2. Low magnification SEM images of a) meso-co 0.5 Sn 0.5, b) meso-co 0.3 Sn 0.7, and c) meso-co 0.1 Sn 09. Figure S3. a) Low and b) Wide angle XRD patterns of meso-co 0.5 Sn 0.5, meso-co 0.3 Sn 0.7 and meso-co 0.1 Sn 09 (Co 3 Sn 2, ; CoSn, ; CoSn 2, ; Sn, from JCPDS cards). 2

4 Figure S4. N 2 sorption isotherms of meso-co 0.5 Sn 0.5, meso-co 0.3 Sn 0.7, and meso-co 0.1 Sn 0.9. Figure S5. Normalized XANES spectra of meso-co 0.5 Sn 0.5, meso-co 0.3 Sn 0.7, and meso- Co 0.1 Sn 0.9 : a) Sn K-edge, and b) Co K-edge. 3

5 Figure S6. Wide angle XRD patterns of meso-co 0.5 Sn 0.5, meso-co 0.3 Sn 0.7, and meso-co 0.1 Sn before template removal. (Co 3 Sn 2, ; CoSn, ; CoSn 2, ; Sn, from PDF cards). Figure S7. a) Net volume change and b) Relative scattering intensity with contained lithium in the electrode material for the initial lithiation delithiation of meso-co x Sn y. The net volume change was calculated by using d 211 spacing of the in operando SAXS data of Figure 2 and 3, assuming the mesostructure as the Ia3d cubic symmetry. 4

6 Figure S8. Color-coded 3D contour and projection map with corresponding voltage profiles showing small angle X-ray scattering data collected from ordered mesoporous Co 0.3 Sn 0.7 electrode during in operando experiment for the 5th cycle. Figure S9. a) The changes in lattice parameter and resolved peak relative intensity calculated results from the (211) reflection with the corresponding dq/dv plot for the 5 th cycle of meso- Co 0.3 Sn 0.5. b) Net volume change and relative scattering intensity with contained lithium in the electrode material for the 5 th cycle of meso-co 0.3 Sn 0.7. The net volume change was calculated by using d (211) spacing of the in operando SAXS data, assuming the mesostructure as the Ia3d cubic symmetry. 5

7 Figure S10. a) Comparison of wide-angle XRD patterns of bulk-co0.3sn0.7 and mesoco0.3sn0.7. Bulk-Co0.3Sn0.7 is prepared as same procedure of meso-co0.3sn0.7 without silica template. b) SEM images of bulk-co0.3sn0.7. Figure S11. Galvanostatic discharge charge profiles: a) bulk-co0.3sn0.7, b) meso-co0.3sn0.7, c) specific capacity vs. cycle number profile, and d) coulombic efficiency profiles for the cycles of bulk-co0.3sn0.7, and meso-co0.3sn0.7. 6

8 Figure S12. Volume resistivity as a function of pressure of meso-co 0.5 Sn 0.5, meso-co 0.3 Sn 0.7, and meso-co 0.1 Sn 0.9. Figure S13. Voltage profiles of meso-co 0.3 Sn 0.7 electrode at various C rates (0.1 2 C rate), collected from the electrochemical experiment in Figure 6a. The x-axis is reacted lithium mole with meso-co 0.3 Sn 0.7 calculated based on the electrochemically active Sn weight from ICP OES analysis result (77 wt. % of Sn incorporation in meso-co 0.3 Sn 0.7 ). 7

9 Figure S14. Galvanostatic discharge-charge profiles of meso-co 0.5 Sn 0.5, meso-co 0.3 Sn 0.7, and meso-co 0.1 Sn 0.9 electrodes, respectively. Current density was 50 ma g -1 (dashed line) and 10 ma g -1 (solid line). The differences between the target composition and elemental analysis results seems to imply the active mass loss during the synthesis process derived from the dissolution of Sn metal phase and limit composition of certain crystal phase within the mesostructure. Because of the ambiguous composition of Co and Sn, the cell of each meso-co x Sn y was conducted to the lowest current density (10 ma g -1 ). The reversible capacities are defined, which are designated as practical theoretical capacity. 8

10 Table S1. ICP OES analysis results of sodium hydroxide solution after template removal. sample Cobalt [atomic %] a) Tin [atomic %] a) meso-co 0.5Sn meso-co 0.3Sn meso-co 0.1Sn a) Calculated amount of dissolved metal element as an atomic percentage at the metal amount of precursors in synthesis. 9