Porous Nitrogen-Doped Carbon Nanotubes Derived from Tubular Polypyrrole for Energy-Storage Applications

Silica nanonetwork confined in nitrogen-doped ordered mesoporous carbon framework for high-performance lithium-ion battery anodes

A new class of nitrogen-doped ordered mesoporous carbon/silica (N-OMC/SiO2) nanocomposites was successfully fabricated via a multi-constituent co-assembly strategy. The N-OMC/SiO2 nanocomposite presented a unique interpenetrating carbon/silica structure whose carbon/silica interface is highly uniform, and thus demonstrated high capacity, good cycling and excellent rate properties.

Rational design of high-surface-area carbon nanotube/microporous carbon core-shell nanocomposites for supercapacitor electrodes

All-carbon-based carbon nanotube (CNT)/microporous carbon core-shell nanocomposites, in which a CNT as the core and high-surface-area microporous carbon as the shell, have been prepared by in situ resorcinol-formaldehyde resin coating of CNTs, followed by carbonization and controlled KOH activation. The obtained nanocomposites have very high Brunauer-Emmett-Teller surface areas (up to 1700 m(2)/g), narrow pore size distribution (<2 nm), and 1D tubular structure within a 3D entangled network. The thickness of the microporous carbon shell can be easily tuned from 20 to 215 nm by changing the carbon precursor/CNT mass ratio. In such a unique core-shell structure, the CNT core could mitigate the key issue related to the low electronic conductivity of microporous carbons. On the other hand, the 1D tubular structure with a short pore-pathway micropore as well as a 3D entangled network could increase the utilization degree of the overall porosity and improve the electrode kinetics. Thus, these CNT/microporous carbon core-shell nanocomposites exhibit a great potential as an electrode material for supercapacitors, which could deliver high specific capacitance of 237 F/g, excellent rate performance with 75% maintenance from 0.1 to 50 A/g, and high cyclability in H2SO4 electrolyte. Moreover, the precisely controlled microporous carbon shells may allow them to serve as excellent model systems for microporous carbons, in general, to illustrate the role of the pore length on the diffusion and kinetics inside the micropores.

Schiff-base polymer derived nitrogen-rich microporous carbon spheres synthesized by molten-salt route for high-performance supercapacitors

A molten-salt route and Schiff-base chemistry are combined to prepare high-capacitive nitrogen-rich microporous carbon spheres. The simple and environmentally friendly synthetic route holds great potential for industrial application.

Elevated rate capability of sulfur wrapped with thin rGO layers for lithium–sulfur batteries

The sulfur nanoparticle wrapped with thin layer of graphene is successfully synthesized by a facile solution impregnation method.

Facile fabrication of N-doped hierarchical porous carbon@CNT coaxial nanocables with high performance for energy storage and conversion

N-Doped hierarchical porous carbon@CNT coaxial nanocables were facilely synthesized and demonstrated to be an ideal carbon nanostructure for electrochemical performance optimization for supercapacitors and in the oxygen reduction reaction.

In situ incorporation of a S, N doped carbon/sulfur composite for lithium sulfur batteries

A novel sulfur–nitrogen co-doped carbon material (SNC), which is obtained by taking polyaniline as the nitrogen-containing carbon precursor and then incorporating sulfur atomsin situas the matrix material for lithium sulfur batteries, is investigated.

Three-dimensional graphene nanosheets/carbon nanotube paper as flexible electrodes for electrochemical capacitors

An ultralight and highly conductive graphene nanosheet/carbon nanotube paper composites have been prepared as high-rate free-standing flexible electrodes for electrochemical capacitors.

Porous nitrogen-doped carbon microspheres derived from microporous polymeric organic frameworks for high performance electric double-layer capacitors

This research presents a simple and efficient method to synthesize porous nitrogen-doped carbon microspheres (PNCM) by the carbonization of microporous poly(terephthalaldehyde-pyrrole) organic frameworks (PtpOF). The common KOH activation process is used to tune the porous texture of the PNCM and produce an activated-PNCM (A-PNCM). The PNCM and A-PNCM with specific surface area of 921 and 1303 m(2)  g(-1) , respectively, are demonstrated as promising candidates for EDLCs. At a current density of 0.5 A g(-1) , the specific capacitances of the PNCM and A-PNCM are 248 and 282 F g(-1) , respectively. At the relatively high current density of 20 A g(-1) , the capacitance remaining is 95 and 154 F g(-1) , respectively. Capacity retention of the A-PNCM is more than 92% after 10000 charge/discharge cycles at a current density of 2 A g(-1) .

Free-standing porous carbon nanofibers-sulfur composite for flexible Li-S battery cathode

Flexible and free-standing sulphur/(PCNFs-CNT) composite (S@PCNFs-CNT) electrode was successfully prepared by infiltrating sulfur into microporous carbon nanofibers-carbon nanotube (PCNFs-CNT) composite. When used as a cathode material for Li-S batteries, the S@PCNFs-CNT exhibits much better cycle performance and rate performance compared to CNT-free S@PCNFs. It delivers a reversible capacity of 637 mA h g(-1) after 100 cycles at 50 mA g(-1) and a rate capability of 437 mA h g(-1) at 1 A g(-1). The improved electrochemical performance is attributed to synergistic effect of the 3D interconnected structure, the additive of CNT, and the uniform distribution of micropores (<2 nm) in the PCNFs-CNT matrix. Our results indicate the potential suitability of PCNFs-CNT for efficient, free-standing, and high-performance batteries.

Rational design of void-involved Si@TiO2 nanospheres as high-performance anode material for lithium-ion batteries

A unique core-shell structure of silicon@titania (Si@TiO2) composite with silicon nanoparticles encapsulated in TiO2 hollow spheres is synthesized by a simple hydrolysis method combined with magnesiothermic reduction method. It is found that the TiO2 shell is effective for improving the electrical conductivity and structural stability. More importantly, the well-designed nanostructure with enough empty space would accommodate the volume change of silicon during the cycling. Reversible capacities of 1911.1 and 795 mAh g(-1) can be obtained at 0.05 C and a high current rate of 1 C, respectively. After 100 cycles at 0.1 C, the composite electrode still maintains a high capacity of 804 mAh g(-1). This excellent cycling stability and high-rate capability can be ascribed to the unique core-shell nanostructure and the synergistic effect between Si and TiO2.

Hierarchically porous carbon encapsulating sulfur as a superior cathode material for high performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are deemed to be a promising energy storage device for next-generation high energy power system. However, insulation of S and dissolution of lithium polysulfides in the electrolyte lead to low utilization of sulfur and poor cycling performance, which seriously hamper the rapid development of Li-S batteries. Herein, we reported that encapsulating sulfur into hierarchically porous carbon (HPC) derived from the soluble starch with a template of needle-like nanosized Mg(OH)2. HPC has a relatively high specific surface area of 902.5 m(2) g(-1) and large total pore volume of 2.60 cm(3) g(-1), resulting that a weight percent of sulfur in S/HPC is up to 84 wt %. When evaluated as cathodes for Li-S batteries, the S/HPC composite has a high discharge capacity of 1249 mAh g(-1) in the first cycle and a Coulombic efficiency as high as 94% with stable cycling over prolonged 100 charge/discharge cycles at a high current density of 1675 mA g(-1). The superior electrochemical performance of S/HPC is closely related to its unique structure, exhibiting the graphitic structure with a high developed porosity framework of macropores in combination with mesopores and micropores. Such nanostructure could shorten the transport pathway for both ions and electrons during prolonged cycling.

N-Doped ordered mesoporous carbon grafted onto activated carbon fibre composites with enhanced activity for the electro-Fenton degradation of Brilliant Red X3B dye

N-Doped ordered mesoporous carbon (N-OMC) was successfully prepared using dicyandiamide (C₂H₄N₄) as the nitrogen source and was grafted onto activated carbon fibres (ACFs) to form carbon composites (ACF@N-OMC).