The Template Synthesis of Double Coaxial Carbon Nanotubes with Nitrogen-Doped and Boron-Doped Multiwalls

Yang, Quan‐Hong; Xu, Wen Yong; Tomita, A.; Kyotani, Takashi

doi:10.1021/ja052357e

Cited by 98 publications

(82 citation statements)

References 6 publications

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“…[ 32,33 ] The weak peak at about 1350 cm −1 (D-band) is associated with the amorphous carbon materials, [ 34 ] while the strong peak at around 1590.0 cm −1 (G-band) is attributed to the vibration of sp 2 -bonded carbon atoms in a 2D hexagonal lattice, [ 35 ] namely the stretching modes of C C bonds in typical graphite. The low-intensity and weak G-band peak suggests a structural imperfection of the graphene sheets such as defects and small crystal domain size, [36][37][38] implying these samples have low graphitization degrees. The components of 30, 40 and 50@Si-granadillas were further confi rmed by X-ray photoelectron spectra (XPS) spectrum in Figure 4 c. The peaks located at 101.1 eV can be assigned to Si 2p, indicating the presence of a layer of silicon oxide species on the surface of all the samples.…”

Section: Resultsmentioning

confidence: 99%

A Green and Facile Way to Prepare Granadilla‐Like Silicon‐Based Anode Materials for Li‐Ion Batteries

Zhang

Rajagopalan

Guo

et al. 2015

Adv Funct Materials

204

109

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A yolk-shell-structured carbon@void@silicon (CVS) anode material in which a void space is created between the inside silicon nanoparticle and the outer carbon shell is considered as a promising candidate for Li-ion cells. Untill now, all the previous yolk-shell composites were fabricated through a templating method, wherein the SiO2 layer acts as a sacrificial layer and creates a void by a selective etching method using toxic hydrofluoric acid. However, this method is complex and toxic. Here, a green and facile synthesis of granadillalike outer carbon coating encapsulated silicon/carbon microspheres which are composed of interconnected carbon framework supported CVS nanobeads is reported. The silicon granadillas are prepared via a modified templating method in which calcium carbonate was selected as a sacrificial layer and acetylene as a carbon precursor. Therefore, the void space inside and among these CVS nanobeads can be formed by removing CaCO3 with diluted hydrochloric acid. As prepared, silicon granadillas having 30% silicon content deliver a reversible capacity of around 1100 mAh g−1 at a current density of 250 mA g−1 after 200 cycles. Besides, this composite exhibits an excellent rate performance of about 830 and 700 mAh g−1 at the current densities of 1000 and 2000 mA g−1, respectively. (≈4200 mAh g −1 ), relatively low discharge potential (≈0.5V vs Li/Li + ), abundance, and environmental benignity. [1][2][3][4][5][6] However, the dramatic volume change (>300%) during lithiation and delithiation processes leads to severe pulverization and continual formation of solid electrolyte interphase (SEI) on the newly formed silicon surfaces, resulting in a large capacity loss. [7][8][9][10][11] Therefore, the cycling performance of silicon-based anodes is still far from satisfactory from a commercial point of view. [ 12 ] Silicon nanoparticles (Si NPs) have been found to tolerate extreme changes in volume with cycling. [ 13 ] Hence, great efforts have been made to improve the cycling stability and electrical conductivity by using various Si-based nanostructures, including Si nanowires, [ 3,14,15 ] porous Si, [16][17][18][19] and conductive agent coated Si such as carbon, [ 18,20,21 ] Ag, [ 22,23 ] and conducting polymer. [ 24 ] Among them, a yolkshell-structured carbon@void@silicon (CVS) composite [ 25,26 ] is quite promising for practical applications, because the void space between the outer carbon shell and the inside Si NP allows the room for volume changes of Si NP without deforming the carbon shell and SEI fi lm, which in turn allows for the growth of a stable SEI on the surface of the outer carbon shell. [ 26 ] Besides, the homogeneous carbon coating shell can prevent the electrolyte ingress and the direct contact of Si NPs with the electrolyte, so the SEI will only be formed on the outer surface of the carbon shell, leading to the high Coulombic effi ciency and improved cycling stability. [ 25 ] For instance, Cui and co-workers achieved a high capacity of ≈2800 mAh g −1 with a very good cycling s...

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Section: Resultsmentioning

confidence: 99%

A Green and Facile Way to Prepare Granadilla‐Like Silicon‐Based Anode Materials for Li‐Ion Batteries

Zhang

Rajagopalan

Guo

et al. 2015

Adv Funct Materials

204

109

View full text Add to dashboard Cite

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“…In addition, the N-doped multi-walled CNTs (MWCNTs) are usually bamboo-shaped, which makes it impossible to fill foreign matters into the hollow core of the N-doped CNTs [94,95]. Compared with the conventional synthesis methods [95][96][97], the AAO template approach shows unique advantage for hetero atom doping in CNTs [93,[98][99][100][101]. The heteroatoms can be selectively doped at the inner or outer surface of CNTs, which is very useful in many applications requiring different polar nature and chemical or physical reaction activity, such as bioseparations and catalyst supports [14,39].…”

Section: Hetero Atom Doping Of the Aao-cntsmentioning

confidence: 99%

“…a pure carbon layer is firstly deposited and then the deposition of N-doped carbon layer. The amount of doped nitrogen can be tuned in the range of N/C atomic ratio < 0.1 [98][99][100][101]. A unique feature of the N-doped CNTs synthesized by the AAO template method is that their hollow cores are empty, which is quite different from the bamboo-like structures of the N-doped CNTs by the conventional synthesis methods [95,[106][107][108].…”

Section: Hetero Atom Doping Of the Aao-cntsmentioning

confidence: 99%

Carbon nanotubes prepared by anodic aluminum oxide template method

et al. 2011

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One of the most unique structural characteristics of carbon nanotubes (CNTs) differentiating from other carbon materials is their hollow nanochannles, which can be utilized for encapsulating and loading foreign matters. The anodic aluminum oxide (AAO) template technique enables the diameter, length, and cap structure control of the replicated CNTs, and thus shows advantages in pore structure control over the traditional CNT growth approaches. This review details the synthesis of CNTs with tunable diameter, length, wall thickness, and crystalline by using the AAO template method. The doping of heteroatoms and filling of foreign matters into AAO-CNTs are also addressed. Moreover, the main challenges and developing trends of the AAO template method are discussed.carbon nanotubes (CNTs), anodic aluminum oxide (AAO) template method, controllability Citation:Hou P X, Liu C, Shi C, et al. Carbon nanotubes prepared by anodic aluminum oxide template method.

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“…For the carbon-based samples, a low-intensity and weak G-band peak suggest a structural imperfection of the graphene sheets such as small crystal domain size or defects. [40][41][42] Therefore, the carbon inside C-Si- During the first discharge process, two reduction peaks at 1.48 and 0.68 V can be observed, which could be related to a multi-step electrochemical reduction process. 6,[47][48] Specifically, the small cathodic peak at 1.48 V can be respectively ascribed to the initial lithium intercalation and the phase transition from …”

Section: Electrochemical Measurementmentioning

confidence: 97%

One-step synthesis of a silicon/hematite@carbon hybrid nanosheet/silicon sandwich-like composite as an anode material for Li-ion batteries

et al. 2016

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The Template Synthesis of Double Coaxial Carbon Nanotubes with Nitrogen-Doped and Boron-Doped Multiwalls

Cited by 98 publications

References 6 publications

A Green and Facile Way to Prepare Granadilla‐Like Silicon‐Based Anode Materials for Li‐Ion Batteries

A Green and Facile Way to Prepare Granadilla‐Like Silicon‐Based Anode Materials for Li‐Ion Batteries

Carbon nanotubes prepared by anodic aluminum oxide template method

One-step synthesis of a silicon/hematite@carbon hybrid nanosheet/silicon sandwich-like composite as an anode material for Li-ion batteries

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