De-long Ma

Nitrogen‐Doped Porous Carbon Nanosheets as Low‐Cost, High‐Performance Anode Material for Sodium‐Ion Batteries

Between the sheets: Sodium-ion batteries are an attractive, low-cost alternative to lithium-ion batteries. Nitrogen-doped porous carbon sheets are prepared by chemical activation of polypyrrole-functionalized graphene sheets. When using the sheets as anode material in sodium-ion batteries, their unique compositional and structural features result in high reversible capacity, good cycling stability, and high rate capability.

Engraving Copper Foil to Give Large‐Scale Binder‐Free Porous CuO Arrays for a High‐Performance Sodium‐Ion Battery Anode

S. Yuan, Dr. X.-L. Huang, D.-L. Ma, Dr. H.-G. Wang, Dr. F.-Z. Meng, Prof. X.-B. Zhang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun, 130022 , P. R. China E-mail: xbzhang@ciac.ac.cn S. Yuan, D.-L. Ma Key Laboratory of Automobile Materials Ministry of Education, and College of Materials Science and Engineering, Jilin University Changchun, 130012 , P. R. China

Electrospun materials for lithium and sodium rechargeable batteries: from structure evolution to electrochemical performance

Electrospinning has been growing increasingly versatile as a promising method to fabricate one dimensional (1D) designed architectures for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). In this review, we have summarized almost all the progress in electrospun electrode materials for LIBs, covering the structure evolution from solid nanofibers into designed 1D nanomaterials, then 1D composites with carbon nanofibers (CNFs), and finally into flexible electrode materials with CNFs. Such a development trend in electrospun electrode materials would meet the battery technology and the strong consumer market demand for portable, ultrathin/lightweight and flexible devices. Along with the avenues of research about electrospun electrode materials for LIBs, electrospun electrode materials for SIBs are a rapidly growing and enormously promising field. As a timely overview, recent studies on electrospun SIB electrode materials are also highlighted. Finally, the emerging challenges and future developments of electrospun electrode materials are concisely provided. We hope this review will provide some inspiration to researchers over a broad range of topics, especially in the fields of energy, chemistry, physics, nanoscience and nanotechnology.

General and controllable synthesis strategy of metal oxide/TiO2 hierarchical heterostructures with improved lithium-ion battery performance.

We demonstrate a simple, efficient, yet versatile strategy for the synthesis of novel hierarchical heterostructures composed of TiO2 nanofiber stem and various metal oxides (MOs) secondary nanostructures, including Co3O4, Fe2O3, Fe3O4, and CuO, by advantageously combining the versatility of the electrospinning technique and hydrothermal growth method, for which the controllable formation process and possible formation mechanism are also investigated. Moreover, as a proof-of-concept demonstration of the functional properties of these hierarchical heterostructures, the Co3O4/TiO2 hierarchical heterostructures are investigated as the lithium-ion batteries (LIBs) anode materials for the first time, which not only delivers a high reversible capacity of 632.5 mAh g-1 and 95.3% capacity retention over 480 cycles, but also shows excellent rate capability with respect to the pristine TiO2 nanofibers. The synergetic effect between Co3O4 and TiO2 as well as the unique feature of hierarchical heterostructures are probably responsible for the enhanced electrochemical performance.

Three-dimensionally ordered macroporous FeF3 and its in situ homogenous polymerization coating for high energy and power density lithium ion batteries

A new hybrid nanostructure composed of three-dimensionally ordered macroporous (3DOM) FeF3 and an homogenous coating of poly(3, 4-ethylenedioxythiophene) (PEDOT) is successfully synthesized using polystyrene (PS) colloidal crystals as hard template, and the coating of PEDOT is achieved through a novel in situ polymerization method. The special nanostructure provides a three-dimensional, continuous, and fast electronic and ionic path in the electrode. Surprisingly, the advantageous combination of 3DOM structure and homogenous coating of PEDOT endows the as-prepared hybrid nanostructures with a stable and high reversible discharge capacity up to 210 mA h g−1 above 2.0 V at room temperature (RT), and a good rate capability of 120 mA h g−1 at a high current density of 1 A g−1, which opens up new opportunities in the development of high performance next-generation lithium-ion batteries (LIBs).

Electrospun V2O5 Nanostructures with Controllable Morphology as High‐Performance Cathode Materials for Lithium‐Ion Batteries

Porous V(2)O(5) nanotubes, hierarchical V(2)O(5) nanofibers, and single-crystalline V(2)O(5) nanobelts were controllably synthesized by using a simple electrospinning technique and subsequent annealing. The mechanism for the formation of these controllable structures was investigated. When tested as the cathode materials in lithium-ion batteries (LIBs), the as-formed V(2)O(5) nanostructures exhibited a highly reversible capacity, excellent cycling performance, and good rate capacity. In particular, the porous V(2)O(5) nanotubes provided short distances for Li(+)-ion diffusion and large electrode-electrolyte contact areas for high Li(+)-ion flux across the interface; Moreover, these nanotubes delivered a high power density of 40.2 kW kg(-1) whilst the energy density remained as high as 201 W h kg(-1), which, as one of the highest values measured on V(2)O(5)-based cathode materials, could bridge the performance gap between batteries and supercapacitors. Moreover, to the best of our knowledge, this is the first preparation of single-crystalline V(2)O(5) nanobelts by using electrospinning techniques. Interestingly, the beneficial crystal orientation provided improved cycling stability for lithium intercalation. These results demonstrate that further improvement or optimization of electrochemical performance in transition-metal-oxide-based electrode materials could be realized by the design of 1D nanostructures with unique morphologies.

Dendritic Ni‐P‐Coated Melamine Foam for a Lightweight, Low‐Cost, and Amphipathic Three‐Dimensional Current Collector for Binder‐Free Electrodes

A highly conductive 3D current collector that is dendritic, lightweight, and robust is synthesized for binder-free electrodes in lithium-ion batteries. It has excellent chemical/electrochemical stability in a wide voltage window (0-5 V) and robust mechanical behavior even after 600 cycles of compression. When active materials are grown in situ on the as-obtained current collector, the resulting cycling stability and rate capability far exceed those of conventional electrodes and other 3D current collectors.

Pure Single-Crystalline Na1.1V3O7.9 Nanobelts as Superior Cathode Materials for Rechargeable Sodium-Ion Batteries

Pure single‐crystalline Na1.1V3O7.9 nanobelts are successfully synthesized for the first time via a facile yet effective strategy. When used as cathode materials for Na‐ion batteries, the novel nanobelts exhibit excellent electrochemical performance. Given the ease and effectiveness of the synthesis route as well as the very promising electrochemical performance, the results obtained may be extended to other next‐generation cathode materials for Na‐ion batteries.

Carbazole-based hole-transporting materials for electroluminescent devices

Two kinds of carbazole-based molecules connected with diphenylamine and carbazole are synthesized by modified Ullmann reaction. Comparative study on their thermal stability, redox behavior, hole injection and transport properties are present. The results demonstrate that the carbazole-based molecules are very promising hole-transporting materials for electroluminescent devices.

Fe3O4-nanoparticle-decorated TiO2 nanofiber hierarchical heterostructures with improved lithium-ion battery performance over wide temperature range

AbstractA facile strategy was designed for the fabrication of Fe3O4-nanoparticle-decorated TiO2 nanofiber hierarchical heterostructures (FTHs) by combining the versatility of the electrospinning technique and the hydrothermal growth method. The hierarchical architecture of Fe3O4 nanoparticles decorated on TiO2 nanofibers enables the successful integration of the binary composite into batteries to address structural stability and low capacity. In the resulting unique architecture of FTHs, the 1D heterostructures relieve the strain caused by severe volume changes of Fe3O4 during numerous charge-discharge cycles, and thus suppress the degradation of the electrode material. As a result, FTHs show excellent performance including higher reversible capacity, excellent cycle life, and good rate performance over a wide temperature range owing to the synergistic effect of the binary composition of TiO2 and Fe3O4 and the unique features of the hierarchical nanofibers.