Tailored nanoparticles and wires of Sn, Ge and Pb inside carbon nanotubes

Haft, Marcel; Grönke, Martin; Gellesch, Markus; Wurmehl, S.; Büchner, B.; Mertig, Michael; Hampel, Silke

doi:10.1016/j.carbon.2016.01.098

Cited by 11 publications

(17 citation statements)

References 36 publications

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“…TGA is mainly used as a measure of the sample purity (i.e., the absence of outside particles which exhibit an increase in mass prior to the combustion of the CNTs), and for the determination of the filling material inside CNTs by performing back calculations based on the mass of the TGA residue [48–49]. This measurement confirms the observations found by SEM that the main difference between the two filling approaches is the filling yield, i.e., samples prepared by the second filling approach are found to have a higher filling yield in comparison with those prepared by the first (solution) filling approach.…”

Section: Resultsmentioning

confidence: 99%

Single-crystalline FeCo nanoparticle-filled carbon nanotubes: synthesis, structural characterization and magnetic properties

Ghunaim¹,

Scholz²,

Damm³

et al. 2018

Beilstein J. Nanotechnol.

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In the present work, we demonstrate different synthesis procedures for filling carbon nanotubes (CNTs) with equimolar binary nanoparticles of the type Fe–Co. The CNTs act as templates for the encapsulation of magnetic nanoparticles and provide a protective shield against oxidation as well as prevent nanoparticle agglomeration. By variation of the reaction parameters, we were able to tailor the sample purity, degree of filling, the composition and size of the filling particles, and therefore, the magnetic properties. The samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), superconducting quantum interference device (SQUID) and thermogravimetric analysis (TGA). The Fe–Co-filled CNTs show significant enhancement in the coercive field as compared to the corresponding bulk material, which make them excellent candidates for several applications such as magnetic storage devices.

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Section: Resultsmentioning

confidence: 99%

Single-crystalline FeCo nanoparticle-filled carbon nanotubes: synthesis, structural characterization and magnetic properties

Ghunaim¹,

Scholz²,

Damm³

et al. 2018

Beilstein J. Nanotechnol.

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“…Mn 3 O 4 @CNT hybrid nanocomposites are obtained after filling CNT with a manganese salt solution and a subsequent reducing step (cf. Refs 19 , 20 ). With a reduction profile of 4 h at 500 °C under Ar/H 2 flow, homogeneously MnO-filled CNT (MnO@CNT) are synthesized.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Magnetization Switching and Energy Storage in Manganese Oxide filled Carbon Nanotubes

Ottmann

Scholz

Haft

et al. 2017

Sci Rep

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The ferrimagnetic and high-capacity electrode material Mn3O4 is encapsulated inside multi-walled carbon nanotubes (CNT). We show that the rigid hollow cavities of the CNT enforce size-controlled nanoparticles which are electrochemically active inside the CNT. The ferrimagnetic Mn3O4 filling is switched by electrochemical conversion reaction to antiferromagnetic MnO. The conversion reaction is further exploited for electrochemical energy storage. Our studies confirm that the theoretical reversible capacity of the Mn3O4 filling is fully accessible. Upon reversible cycling, the Mn3O4@CNT nanocomposite reaches a maximum discharge capacity of 461 mA h g−1 at 100 mA g−1 with a capacity retention of 90% after 50 cycles. We attribute the good cycling stability to the hybrid nature of the nanocomposite: (1) Carbon encasements ensure electrical contact to the active material by forming a stable conductive network which is unaffected by potential cracks of the encapsulate. (2) The CNT shells resist strong volume changes of the encapsulate in response to electrochemical cycling, which in conventional (i.e., non-nanocomposite) Mn3O4 hinders the application in energy storage devices. Our results demonstrate that Mn3O4 nanostructures can be successfully grown inside CNT and the resulting nanocomposite can be reversibly converted and exploited for lithium-ion batteries.

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“…In addition to separated spherical nanoparticles, encapsulates in CoSn@CNT and Sn@CNT form also nanowires up to 1 μm length (see Figure 3h and Figure 15). In either case, the encapsulates fill the complete inner diameter of the CNT, which is about 50 nm [44]. In summary, the results show that our synthesis approaches result in CNT filled with nanoparticles whose diameters are limited by the inner diameter of the CNT.…”

Section: Synthesis and Characterization Of Filled Cntmentioning

confidence: 75%

“…Mostly, CNT of type PR-24-XT-HHT (Pyrograf Products, Inc., Cedarville OH, USA) have been used as templates. For introducing materials into the inner cavity of the CNT, mainly extensions of solution-based approaches reported in [38][39][40][41][42][43] have been applied [44,45]. This is illustrated by the example of Mn3O4@CNT which has been obtained by filling CNT with a manganese salt solution and a subsequent reducing step yielding homogeneously MnO-filled CNT (MnO@CNT) [4].…”

Section: Synthesis and Characterization Of Filled Cntmentioning

confidence: 99%

Filled Carbon Nanotubes as Anode Materials for Lithium-Ion Batteries

et al. 2020

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Downsizing well-established materials to the nanoscale is a key route to novel functionalities, in particular if different functionalities are merged in hybrid nanomaterials. Hybrid carbon-based hierarchical nanostructures are particularly promising for electrochemical energy storage since they combine benefits of nanosize effects, enhanced electrical conductivity and integrity of bulk materials. We show that endohedral multiwalled carbon nanotubes (CNT) encapsulating high-capacity (here: conversion and alloying) electrode materials have a high potential for use in anode materials for lithium-ion batteries (LIB). There are two essential characteristics of filled CNT relevant for application in electrochemical energy storage: (1) rigid hollow cavities of the CNT provide upper limits for nanoparticles in their inner cavities which are both separated from the fillings of other CNT and protected against degradation. In particular, the CNT shells resist strong volume changes of encapsulates in response to electrochemical cycling, which in conventional conversion and alloying materials hinders application in energy storage devices.(2) Carbon mantles ensure electrical contact to the active material as they are unaffected by potential cracks of the encapsulate and form a stable conductive network in the electrode compound. Our studies confirm that encapsulates are electrochemically active and can achieve full theoretical reversible capacity. The results imply that encapsulating nanostructures inside CNT can provide a route to new high-performance nanocomposite anode materials for LIB.

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Tailored nanoparticles and wires of Sn, Ge and Pb inside carbon nanotubes

Cited by 11 publications

References 36 publications

Single-crystalline FeCo nanoparticle-filled carbon nanotubes: synthesis, structural characterization and magnetic properties

Single-crystalline FeCo nanoparticle-filled carbon nanotubes: synthesis, structural characterization and magnetic properties

Electrochemical Magnetization Switching and Energy Storage in Manganese Oxide filled Carbon Nanotubes

Filled Carbon Nanotubes as Anode Materials for Lithium-Ion Batteries

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