Highly Conductive and Strain‐Released Hybrid Multilayer Ge/Ti Nanomembranes with Enhanced Lithium‐Ion‐Storage Capability

Yan, Chenglin; Xi, Wang; Si, Wenping; Deng, Junwen; Schmidt, Oliver G.

doi:10.1002/adma.201203458

Cited by 127 publications

(117 citation statements)

References 36 publications

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“…In addition, the proposed technology can be extended, and the helical antenna can be prepared in a single fabrication process out of the planar layout, accommodating various functional elements, including energy storage, 46,47 active electronics, 39 and magnetic 48 and fluidic 41 sensorics, hence realizing in vivo smart implants based on multifunctional compact electronics. 49 …”

Section: Resultsmentioning

confidence: 99%

Compact helical antenna for smart implant applications

2015

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Smart implants are envisioned to revolutionize personal health care by assessing physiological processes, for example, upon wound healing, and communicating these data to a patient or medical doctor. The compactness of the implants is crucial to minimize discomfort during and after implantation. The key challenge in realizing small-sized smart implants is high-volume cost-and time-efficient fabrication of a compact but efficient antenna, which is impedance matched to 50 Ω, as imposed by the requirements of modern electronics. Here, we propose a novel route to realize arrays of 5.5-mm-long normal mode helical antennas operating in the industry-scientific-medical radio bands at 5.8 and 2.4 GHz, relying on a self-assembly process that enables large-scale high-yield fabrication of devices. We demonstrate the transmission and receiving signals between helical antennas and the communication between an antenna and a smartphone. Furthermore, we successfully access the response of an antenna embedded in a tooth, mimicking a dental implant. With a diameter of~0.2 mm, these antennas are readily implantable using standard medical syringes, highlighting their suitability for in-body implant applications.

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Section: Resultsmentioning

confidence: 99%

Compact helical antenna for smart implant applications

2015

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“…After 400 cycles at 40C rate, the capacity was 1000 mAh g À1 . Surprisingly, most studies on Ge anodes have been performed on nano-Ge with dimensions 100 nm [267,[269][270][271] or even 3 nm [272] missing the main interest of the germanium element, presumably by continuity with the prior works on Si where the nano-size was mandatory. In particular, Ge nanowires have been grown by CVD [273], like Si nanowires.…”

Section: Germaniummentioning

confidence: 96%

Anodes for Li-Ion Batteries

et al. 2016

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Lithium-ion batteries (LiBs) have made considerable progress since the first commercial one by Sony in 1991, which had LiCoO 2 and graphite as active elements of the positive and negative electrodes, respectively. The LiBs are now the primary energy storage devices in the transportation and communications, from portable use in computers, up to electric and hybrid vehicles. More recently, they have also been used as back-up supply units, frequency regulators (load leveling) to integrate on smart grids the electricity produced by windmills and photovoltaic plants (for a recent review, see [1]). These applications require high energy densities, high power, and safety among others. Considerable efforts have been made to propose other electrodes to fulfill these requirements. We have recently reviewed the works and progress concerning the materials for the positive electrode [2][3][4][5][6]. The present work is devoted to the materials for the negative electrode counterpart. It is common to use the terminology anode and cathode for the negative and positive electrodes, respectively, although the electrodes play alternatively the role of anode and cathode during the charge and discharge process. We shall use this terminology in the following for conciseness purposes only.An ideal active anode element should fulfill the following requirements as follows: (1) It must be light and accommodate as much Li as possible to optimize the gravimetric capacity. (2) Its redox potential with respect to Li 0 /Li + must be as small as possible at any Li-concentration. The reason is that this potential is subtracted to the redox potential of the cathode material to give the overall voltage of the cell, and smaller voltage means smaller energy density. (3) It must possess good electronic and ionic conductivities since faster motion of the lithium ions and the electrons also mean higher power density of the cell. (4) It must not be soluble in the solvents of the electrolyte and not react with the lithium salt. (5) It must be safe, i.e. avoid any thermal runaway of the battery, a criterion that is not independent of the previous one, but deserves special attention, especially for use in transportation such as electric vehicles and planes. (6) It must be cheap and environmentally friendly. The different materials proposed as anode elements for Li-ion batteries must be discussed with respect to these different criteria.The graphite is still the most used anode material and is still the reference. The first works giving evidence of the insertion of lithium in graphite date from 1955 [7], confirmed by the synthesis of LiC 6 in 1965 [8]. The synthesis of LiC 6 , however, was not obtained by electrochemical process at that time. Another decade was spent before Besenhard and Eichinger discovered the reversible intercalation of lithium in graphite, proposing this material as an anode in 1976 [9,10]. Increasing the Li content in LiC 6 is possible [8], but no reversible cycling beyond LiC 6 could ever be obtained. The graphite anode can thus be cyc...

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“…[18][19][20][21][22][23][24][25] Nevertheless, the practical application of Ge is hindered by the pulverization problem caused by the large volume changes during Li insertion/extraction processes, thus leading to the loss of electrical conductivity and consequently a rapid capacity decline upon cycling. [26][27][28][29][30][31] Previously studies have demonstrated that decreasing the Ge particle size into the nanometer range could alleviate the stress produced during Li uptake and release processes and suppress the tendency of the nanostructure to fracture. [32][33][34][35] Moreover, the nanostructure can facilitate the diffusion of Li ion, resulting in high rate capability.…”

Section: Introductionmentioning

confidence: 99%

Ge Nanoparticles Encapsulated in Nitrogen-Doped Reduced Graphene Oxide as an Advanced Anode Material for Lithium-Ion Batteries

Zhu

Zhou

et al. 2014

J. Phys. Chem. C

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Ge nanoparticles/C composites are desirable electrode materials for high energy and power density lithium-ion batteries. However, the production of well-dispersed Ge nanoparticles in a carbon network remains a challenge because of rapid grain growth during high-temperature thermal reduction. Herein, we report a PVP-assisted hydrolysis approach for fabricating Ge nanoparticles/reduced graphene oxide composite (denoted as Ge/RGO) made of ~5 nm Ge nanoparticles that are uniformly distributed within a nitrogen-doped RGO carbon matrix. The Ge/RGO composite exhibits an initial discharge capacity of 1475 mA h g −1 and a reversible capacity of 700 mA h g −1 after 200 cycles at a current density of 0.5 A g −1 . Moreover, Ge/RGO shows a capacity of 210 mA h g −1 even at a high current density of 10 A g −1 . The excellent performance of the Ge/RGO composite is attributed to its unique nanostructure, including Ge nanoparticles, homogeneous particle distribution, and highly conductive RGO carbon matrix.These properties alleviate the pulverization problem, prevent Ge particle aggregation, and facilitate electron and lithium ion transportation.

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Highly Conductive and Strain‐Released Hybrid Multilayer Ge/Ti Nanomembranes with Enhanced Lithium‐Ion‐Storage Capability

Cited by 127 publications

References 36 publications

Compact helical antenna for smart implant applications

Compact helical antenna for smart implant applications

Anodes for Li-Ion Batteries

Ge Nanoparticles Encapsulated in Nitrogen-Doped Reduced Graphene Oxide as an Advanced Anode Material for Lithium-Ion Batteries

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