Preparation of Ge nanotube arrays from an ionic liquid for lithium ion battery anodes with improved cycling stability

Electrode materials with three-dimensional (3D) mesoporous structures possess superior features, such as shortened solid-phase lithium diffusion distance, large pore volume, full lithium ion accessibility, and a high specific area, which can facilitate fast lithium ion transport and electron transfer between solid/electrolyte interfaces. In this work, we introduce a facile synthesis route for the preparation of a 3D nanoarchitecture of Ge coated with carbon (3D-Ge/C) via a carbothermal reduction method in an inert atmosphere. The 3D-Ge/C showed excellent cyclability: almost 86.8% capacity retention, corresponding to a charge capacity of 1216 mAh g -1 even after 1000 cycles at a 2 C-rate. Surprisingly, the high average reversible capacity of 1122 mAh g -1 was maintained at a high charge rate of 100 C (160 A g -1 ). Even at an ultrahigh charge rate of 400 C (640 A g -1 ), an average capacity of 429 mAh g -1 was attained. Further, the full cell composed of 3D-Ge/C anode and LiCoO2 cathode exhibited excellent rate capability and cyclability with 94.7% capacity retention over 50 cycles. 3D-Ge/C, which offers a high energy density like batteries as well as a high power density like supercapacitors, is expected to be used in a wide range of electrochemical devices.A novel, facile synthetic route has been proposed to prepare a 3D nanoarchitecture Ge coated with carbon (3D-Ge/C) via a carbothermal reduction. The GeO 2 /PVP composite was carbonized in an argon atmosphere at 775 °C for 1 h to carbonize the PVP. During carbonization, the carbothermal reduction of GeO 2 occurred and simultaneously formed Ge within a 3D structure.

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“…2i. 44,45 Nevertheless, it is noticeable that both charge and discharge profiles hardly changed from the second cycle, as shown in the Fig. 3a.…”

Section: Please Do Not Adjust Marginsmentioning

confidence: 90%

Mass-scalable synthesis of 3D porous germanium–carbon composite particles as an ultra-high rate anode for lithium ion batteries

Ngo

Kim

et al. 2015

Energy Environ. Sci.

203

114

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“…Therefore, tremendous efforts have been devoted into fabricating nanostructured materials, such as nanoparticles, [17,[37][38][39] nanowires, [13][14][15]40] nanotubes, [16,[41][42][43] nanofibers, [44,45] and nanorods. Furthermore, the bulk-form germanium materials have limited active area, which leads to sluggish lithium-ion diffusion.…”

Section: Nanosized Structuresmentioning

confidence: 99%

Section: Porous/mesoporous Structuresmentioning

confidence: 99%

Unique Structural Design and Strategies for Germanium‐Based Anode Materials Toward Enhanced Lithium Storage

Wang

Zhou

et al. 2017

Advanced Energy Materials

113

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Germanium‐based materials are arousing increasing interest as anodes for lithium‐ion batteries, stemming from the intrinsic physical and chemical advantages of germanium. This progress report provides a brief review on the current development of germanium‐based materials in lithium storage. The state‐of‐the‐art strategies to achieve enhanced electrochemical properties are highlighted, with their main aim being to resolve the trickiest issue: vast volume changes in germanium during cycling. These strategies include structural modification, modification by surface coating, forming germanium‐based alloys, and forming binary or ternary germanium‐based composites. The recent work on a novel composite of germanium and tin particles encapsulated in double‐concentric carbon hollow spheres is also presented here, with an emphasis on the relationship between structural design and improved performance.

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“…However, the overall electrochemical performance is significantly dependent on the mixed level of carbon and active electrode materials. Theoretical studies show that nano‐electrode materials are highly active and reactive after lithiation/sodiation, which will drive them to form a low‐energy crystalline state in thermodynamics . The lithiated amorphous product prefers to nucleate and grow into large amorphous particles by long‐distance diffusion in dynamics when without effective isolation, resulting in capacity loss.…”

Section: Introductionmentioning

confidence: 99%

Two‐Dimensional Germanium Sulfide Nanosheets as an Ultra‐Stable and High Capacity Anode for Lithium Ion Batteries

Wang

Yang

et al. 2019

Chemistry A European J

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Lithium ion batteries (LIBs) at present still suffer from low rate capability and poor cycle life during fast ion insertion/extraction processes. Searching for high-capacity and stable anode materials is still an ongoing challenge. Herein, af acile strategy for the synthesis of ultrathin GeS 2 nanosheetsw ith the thickness of 1.1 nm is reported. When used as anodes for LIBs, the two-dimensional (2D) structure can effectively increase the electrode/electrolyte interface area, facilitate the iont ransport, and buffer the volume expansion. Benefiting from these merits,t he as-synthesized GeS 2 nanosheets deliver high specific capacity (1335 mAh g À1 at 0.15 Ag À1 ), extraordinary rate performance (337 mAh g À1 at 15 Ag À1 )a nd stable cycling performance (974 mAh g À1 after 200 cycles at 0.5Ag À1 ). Importantly,o ur fabricated Li-ion full cells manifest an impressive specific capacity of 577 mAh g À1 after 50 cycles at 0.1 Ag À1 and ah igh energy density of 361 Wh kg À1 at ap owerd ensity of 346 Wkg À1 .F urthermore, the electrochemical reaction mechanism is investigated by the means of ex-situh igh-resolution transmission electron microscopy.T hese results suggest that GeS 2 can use to be an alternative anode material and encourage more efforts to develop other high-performance LIBs anodes.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

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Preparation of Ge nanotube arrays from an ionic liquid for lithium ion battery anodes with improved cycling stability

Cited by 68 publications

References 23 publications

Mass-scalable synthesis of 3D porous germanium–carbon composite particles as an ultra-high rate anode for lithium ion batteries

Mass-scalable synthesis of 3D porous germanium–carbon composite particles as an ultra-high rate anode for lithium ion batteries

Unique Structural Design and Strategies for Germanium‐Based Anode Materials Toward Enhanced Lithium Storage

Two‐Dimensional Germanium Sulfide Nanosheets as an Ultra‐Stable and High Capacity Anode for Lithium Ion Batteries

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