Alkanethiol-Passivated Ge Nanowires as High-Performance Anode Materials for Lithium-Ion Batteries: The Role of Chemical Surface Functionalization

We demonstrate that dodecanethiol monolayer passivation can significantly enhance the anode performance of germanium (Ge) nanowires in lithium-ion batteries. The dodecanethiol-passivated Ge nanowires exhibit an excellent electrochemical performance with a reversible specific capacity of 1130 mAh/g a...

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Bibliographic Details
Published in:ACS nano 2012-11, Vol.6 (11), p.9932-9942
Main Authors: Yuan, Fang-Wei, Yang, Hong-Jie, Tuan, Hsing-Yu
Format: Article
Language:English
Subjects:
Alkanes - chemistry
Anodes
Devices
Electric Power Supplies
Electrodes
Equipment Design
Equipment Failure Analysis
Germanium
Germanium - chemistry
Ions
Lithium - chemistry
Lithium-ion batteries
Monolayers
Nanostructure
Nanotubes - chemistry
Nanotubes - ultrastructure
Nanowires
Particle Size
Polyvinylidene fluorides
Sulfhydryl Compounds - chemistry
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Summary:We demonstrate that dodecanethiol monolayer passivation can significantly enhance the anode performance of germanium (Ge) nanowires in lithium-ion batteries. The dodecanethiol-passivated Ge nanowires exhibit an excellent electrochemical performance with a reversible specific capacity of 1130 mAh/g at 0.1 C rate after 100 cycles. The functionalized Ge nanowires show high-rate capability having charge and discharge capacities of ∼555 mAh/g at high rates of 11 C. The functionalized Ge nanowires also performed well at 55 °C, showing their thermal stability at high working temperatures. Moreover, full cells using a LiFePO4 cathode were assembled and the electrodes still have stable capacity retention. An aluminum pouch type lithium cell was also assembled to provide larger current (∼30 mA) for uses on light-emitting-diodes (LEDs) and audio devices. Investigation of the role of organic monolayer coating showed that the wires formed a robust nanowire/PVDF network through strong C–F bonding so as to maintain structure integrity during the lithiation/delithiation process. Organic monolayer-coated Ge nanowires represent promising Ge–C anodes with controllable low carbon content (ca. 2–3 wt %) for high capacity, high-rate lithium-ion batteries and are readily compatible with the commercial slurry-coating process for cell fabrication.
ISSN:1936-0851
1936-086X
DOI:10.1021/nn303519g