Elucidation of the Local and Long-Range Structural Changes that Occur in Germanium Anodes in Lithium-Ion Batteries

Metallic germanium is a promising anode material in secondary lithium-ion batteries (LIBs) due to its high theoretical capacity (1623 mAh/g) and low operating voltage, coupled with the high lithium-ion diffusivity and electronic conductivity of lithiated Ge. Here, the lithiation mechanism of micron-sized Ge anodes has been investigated with X-ray diffraction (XRD), pair distribution function (PDF) analysis, and in-/ex-situ high-resolution 7Li solid-state nuclear magnetic resonance (NMR), utilizing the structural information and spectroscopic fingerprints obtained by characterizing a series of relevant LixGey model compounds. In contrast to previous work, which postulated the formation of Li9Ge4 upon initial lithiation, we show that crystalline Ge first reacts to form a mixture of amorphous and crystalline Li7Ge3 (space group P3212). Although Li7Ge3 was proposed to be stable in a recent theoretical study of the Li–Ge phase diagram (Morris, A. J.; Grey, C. P.; Pickard, C. J. Phys. Rev. B: Condens. Matter Ma...

[1]  A. Jain,et al.  Destabilization of LiH by Li Insertion into Ge , 2013 .

[2]  Yi Cui,et al.  Understanding Phase Transformation in Crystalline Ge Anodes for Li- Ion Batteries , 2014 .

[3]  Jaephil Cho,et al.  Catalytic role of Ge in highly reversible GeO2/Ge/C nanocomposite anode material for lithium batteries. , 2013, Nano letters.

[4]  H. Schäfer,et al.  Die Struktur der Phase Li7Ge2 / The Structure of Li7Ge2 , 1972 .

[5]  Wei-Jun Zhang.  A review of the electrochemical performance of alloy anodes for lithium-ion batteries , 2011 .

[6]  J. Jamnik,et al.  Nanocrystallinity effects in lithium battery materials , 2003 .

[7]  M. Winter,et al.  Reversible Storage of Lithium in Three-Dimensional Macroporous Germanium , 2014 .

[8]  Phl Peter Notten,et al.  Lithium-Ion (De)Insertion Reaction of Germanium Thin-Film Electrodes: An Electrochemical and In Situ XRD Study , 2009 .

[9]  Steve W. Martin,et al.  Electrochemical behavior of Ge and GeX2 (X = O, S) glasses: Improved reversibility of the reaction of Li with Ge in a sulfide medium , 2008 .

[10]  Jae-Hun Kim,et al.  Li-alloy based anode materials for Li secondary batteries. , 2010, Chemical Society reviews.

[11]  D. Shi,et al.  A unique sandwich-structured C/Ge/graphene nanocomposite as an anode material for high power lithium ion batteries , 2013 .

[12]  C. S. Fuller,et al.  Diffusion of Lithium into Germanium and Silicon , 1953 .

[13]  H. Pfeiffer,et al.  Chemical Sorption of Carbon Dioxide (CO2) on Lithium Oxide (Li2O) , 2006 .

[14]  P. Lippens,et al.  7Li NMR Knight Shifts in Li−Sn Compounds: MAS NMR Measurements and Correlation with DFT Calculations , 2010 .

[15]  Surface chemistry and electrical properties of germanium nanowires. , 2004, Journal of the American Chemical Society.

[16]  Ting Zhu,et al.  In Situ TEM Experiments of Electrochemical Lithiation and Delithiation of Individual Nanostructures , 2012 .

[17]  Rangeet Bhattacharyya,et al.  Real-time NMR investigations of structural changes in silicon electrodes for lithium-ion batteries. , 2009, Journal of the American Chemical Society.

[18]  T. D. Hatchard,et al.  In Situ XRD and Electrochemical Study of the Reaction of Lithium with Amorphous Silicon , 2004 .

[19]  D. H. Wood,et al.  The crystal structure of Li15Ge4 , 1965 .

[20]  M. Winter,et al.  Structural and dynamic characterization of Li(12)Si(7) and Li(12)Ge(7) using solid state NMR. , 2012, Solid state nuclear magnetic resonance.

[21]  Yi Cui,et al.  High capacity Li ion battery anodes using ge nanowires. , 2008, Nano letters.

[22]  Chris J Pickard,et al.  Ab initio random structure searching , 2011, Journal of physics. Condensed matter : an Institute of Physics journal.

[23]  A. Pelton,et al.  The Ge- Li (Germanium-Lithium) system , 1997 .

[24]  C. C. Ahn,et al.  Nanocrystalline and Thin Film Germanium Electrodes with High Lithium Capacity and High Rate Capabilities , 2004 .

[25]  Andrew J. Morris,et al.  Thermodynamically stable lithium silicides and germanides from density functional theory calculations , 2014, 1402.6233.

[26]  Seung-Don Choi,et al.  The Current Move of Lithium Ion Batteries Towards the Next Phase , 2012 .

[27]  S J L Billinge,et al.  PDFfit2 and PDFgui: computer programs for studying nanostructure in crystals , 2007, Journal of physics. Condensed matter : an Institute of Physics journal.

[28]  Cheol‐Min Park,et al.  Electrochemical Characterizations of Germanium and Carbon-Coated Germanium Composite Anode for Lithium-Ion Batteries , 2008 .

[29]  C. J. Kerr,et al.  Revealing lithium–silicide phase transformations in nano-structured silicon-based lithium ion batteries via in situ NMR spectroscopy , 2014, Nature Communications.

[30]  J. Tarascon,et al.  Pair distribution function analysis and solid state NMR studies of silicon electrodes for lithium ion batteries: understanding the (de)lithiation mechanisms. , 2011, Journal of the American Chemical Society.

[31]  R. Nesper,et al.  Novel Metastable Germanium Modifications allo‐Ge and 4H‐Ge from Li7Ge12 , 1982 .

[32]  Jing Li,et al.  An In Situ X-Ray Diffraction Study of the Reaction of Li with Crystalline Si , 2007 .

[33]  Mark N. Obrovac,et al.  Structural changes in silicon anodes during lithium insertion/extraction , 2004 .

[34]  Xiqian Yu,et al.  Amorphous hierarchical porous GeO(x) as high-capacity anodes for Li ion batteries with very long cycling life. , 2011, Journal of the American Chemical Society.

[35]  Chris J Pickard,et al.  High-pressure phases of silane. , 2006, Physical review letters.

[36]  T. Ungár.  Microstructural parameters from X-ray diffraction peak broadening , 2004 .