Taiqiang Chen

Electrospun carbon nanofibers as anode materials for sodium ion batteries with excellent cycle performance

A simple and scalable electrospinning process followed by thermal treatment was used to fabricate carbon nanofibers (CFs). The as-prepared CFs were investigated as anode materials for sodium ion batteries (SIBs). Remarkably, due to their weakly ordered turbostratic structure and a large interlayer spacing between graphene sheets, the CFs exhibit a dominant adsorption/insertion sodium storage mechanism that shows high reversibility. As a result, the CFs show excellent electrochemical performance, especially cycle stability (97.7% capacity retention ratio over 200 cycles). Reversible capacities of 233 and 82 mA h g−1 are obtained for the CFs at a current density of 0.05 A g−1 and even a high current density of 2 A g−1, respectively. The excellent cycle performance, high capacity and good rate capability make the CFs promising candidates for practical SIBs.

Mesoporous nanostructured Co3O4 derived from MOF template: a high-performance anode material for lithium-ion batteries

Mesoporous nanostructured Co3O4 was prepared by the direct pyrolysis of a Co-based metal organic framework (MOF) template at a relatively low temperature rather than a high temperature. When tested as an anode material for lithium-ion batteries (LIBs), this porous Co3O4 exhibited a greatly enhanced performance of lithium storage. The capacity of the porous Co3O4 retained 913 mA h g−1 after 60 cycles at a current rate of 200 mA g−1. Excellent rate capability was also achieved. We also found out that the Co3O4 prepared from the MOF template at a relatively low temperature has better electrochemical performance than that prepared at high temperature.

Fast synthesis of carbon microspheres via a microwave-assisted reaction for sodium ion batteries

A fast microwave-assisted approach was developed to fabricate carbon microspheres (CSs) using sucrose as the precursor in a microwave system. After thermal treatment at 300, 500, 700 and 1000 °C, the CSs were used as anode materials for sodium ion batteries (SIBs). The results show that CSs treated at 500 °C exhibit a maximum capacity of 183 mA h g−1 at a current density of 30 mA g−1 after 50 cycles, and even at a high current density of 1000 mA g−1 a capacity of 83 mA h g−1 is maintained. The high capacity, good cycling stability and excellent rate performance of CSs, due to their unique spherical structure, make them a promising candidate for anode materials for SIBs.

MoS2–reduced graphene oxide composites synthesized via a microwave-assisted method for visible-light photocatalytic degradation of methylene blue

MoS2–reduced graphene oxide (RGO) composites were successfully synthesized via microwave-assisted reduction of graphite oxide in a MoS2 precursor aqueous solution using a microwave system. The morphology, structure and photocatalytic performance in the degradation of methylene blue (MB) were characterized by scanning electron microscopy, X-ray diffraction, electrochemical impedance spectra and UV-vis absorption spectroscopy, respectively. The results show that the MoS2–RGO composites exhibit enhanced photocatalytic performance in the degradation of MB with a maximum degradation rate of 99% under visible light irradiation for 60 min. This excellent photocatalytic activity is due to the contribution from the reduced electron–hole pair recombination, the enhanced light absorption and the increased dye adsorptivity with the introduction of RGO in the composite.

One-step synthesis of SnO2–reduced graphene oxide–carbon nanotube composites via microwave assistance for lithium ion batteries

A facile one-step microwave-assisted method was developed to fabricate SnO2–reduced graphene oxide (RGO)–carbon nanotube (CNT) composites. The as-prepared composites were applied as anode materials for lithium ion batteries and it is found that RGO and CNTs play an important role in the enhancement of the electrochemical performance due to a synergistic effect of SnO2, RGO and CNTs, in which RGO sheets support SnO2 nanoparticles and CNTs act as wires conductively connecting the large RGO sheets together. A SnO2–RGO–CNT composite with 60 wt.% SnO2 achieves a maximum capacity of 502 mA h g−1 after 50 cycles at 100 mA g−1 and even at a high current density of 1000 mA g−1, a capacity of 344 mA h g−1 is maintained.

Carbon microspheres via microwave-assisted synthesis as counter electrodes of dye-sensitized solar cells.

Carbon microspheres (CSs) were successfully fabricated and used as counter electrodes of dye-sensitized solar cells (DSSCs). CSs were obtained through a fast microwave-assisted approach using sucrose as the precursor in a microwave system and subsequent thermal treatment at 600, 800 and 1000°C. A maximum photovoltaic conversion efficiency of 5.5% is achieved for DSSCs based on the CSs counter electrodes, which is comparable to the cell based on conventional Pt counter electrode at one sun (AM 1.5 G, 100 mW cm(-2)). The results suggest the CSs to be a potential candidate for counter electrodes of DSSCs.

Ionic conductivity of β-cyclodextrin-polyethylene-oxide/alkali-metal-salt complex.

Highly conductive, crystalline, polymer electrolytes, β-cyclodextrin (β-CD)-polyethylene oxide (PEO)/LiAsF6 and β-CD-PEO/NaAsF6 , were prepared through supramolecular self-assembly of PEO, β-CD, and LiAsF6 /NaAsF6 . The assembled β-CDs form nanochannels in which the PEO/X(+) (X=Li, Na) complexes are confined. The nanochannels provide a pathway for directional motion of the alkali metal ions and, at the same time, separate the cations and the anions by size exclusion.

Kinetics and isotherm studies on electrosorption of NaCl by activated carbon fiber, carbon nanotube and carbon nanotube-carbon nanofiber composite films

In this paper, the structures of commercial activated carbon fiber (ACF), carbon nanotube (CNT) and home-made carbon nanotube-carbon nanofiber (CNT-CNF) films are characrerized and compare their electrochemical behaviors in NaCl solutions in order to study the electrosorption mechanism.