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Weizhong Qian

Bio: Weizhong Qian is an academic researcher from Tsinghua University. The author has contributed to research in topics: Carbon nanotube & Catalysis. The author has an hindex of 56, co-authored 182 publications receiving 13551 citations. Previous affiliations of Weizhong Qian include Dalian Institute of Chemical Physics & University of Hawaii at Manoa.


Papers
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Journal ArticleDOI
01 Nov 2010-Carbon
TL;DR: In this paper, a self-limiting deposition of nanoscale MnO2 on the surface of graphene under microwave irradiation was proposed to synthesize graphene-MnO2 composites.

1,263 citations

Journal ArticleDOI
TL;DR: Graphene has attracted great attention in various application areas, such as energy-storage materials, polymer composites, liquid crystal devices, and mechanical resonators.
Abstract: Owing to its unique electrical, thermal, and mechanical properties, graphene has attracted great attention in various application areas, such as energy-storage materials, [ 1–3 ] free-standing paper-like materials, [ 4–6 ] polymer composites, [ 7–9 ] liquid crystal devices, [ 10 ] and mechanical resonators. [ 11 , 12 ] Approaches for preparing graphene include micromechanical cleavage, [ 11 , 13 , 14 ]

1,203 citations

Journal ArticleDOI
01 Feb 2010-Carbon
TL;DR: In this paper, a graphene nanosheet (GNS)/polyaniline (PANI) composite was synthesized using in situ polymerization and the morphology and microstructure of samples were examined by scanning electron microscopy (SEM), TEM, X-ray diffraction (XRD), and Raman spectroscopy.

969 citations

Journal ArticleDOI
Jia-Qi Huang1, Qiang Zhang1, Hong-Jie Peng1, Xinyan Liu1, Weizhong Qian1, Fei Wei1 
TL;DR: In this article, an ion selective membrane is proposed to improve the stability and coulombic efficiency of lithium-sulfur batteries, where the sulfonate-ended perfluoroalkyl ether groups on the ionic separators are connected by pores or channels that are around several nanometers in size.
Abstract: Lithium–sulfur batteries attract great attention due to their high energy density, while their real applications are still hindered by the rapid capacity degradation. Despite great efforts devoted to solving the polysulfide shuttle between the cathode and anode electrodes, it remains a serious challenge to build highly-stable lithium–sulfur batteries. Herein we demonstrate a strategy of introducing an ion selective membrane to improve the stability and coulombic efficiency of lithium–sulfur batteries. The sulfonate-ended perfluoroalkyl ether groups on the ionic separators are connected by pores or channels that are around several nanometers in size. These SO3− groups-coated channels allow ion hopping of positively charged species (Li+) but reject hopping of negative ions, such as polysulfide anions (Sn2−) in this specific case due to the coulombic interactions. Consequently, this cation permselective membrane acts as an electrostatic shield for polysulfide anions, and confines the polysulfides on the cathode side. An ultra-low decay rate of 0.08% per cycle is achieved within the initial 500 cycles for the membrane developed in this work, which is less than half that of the routine membranes. Such an ion selective membrane is versatile for various electrodes and working conditions, which is promising for the construction of high performance batteries.

603 citations

Journal ArticleDOI
Qiang Zhang1, Jia-Qi Huang1, Weizhong Qian1, Yingying Zhang1, Fei Wei1 
22 Apr 2013-Small
TL;DR: In this article, the authors selected carbon nanotubes (CNTs) with sp(2) carbon bonding, excellent mechanical, electrical, thermal, as well as transport properties to demonstrate the road of nanomaterials towards industry.
Abstract: The innovation on the low dimensional nanomaterials brings the rapid growth of nano community. Developing the controllable production and commercial applications of nanomaterials for sustainable society is highly concerned. Herein, carbon nanotubes (CNTs) with sp(2) carbon bonding, excellent mechanical, electrical, thermal, as well as transport properties are selected as model nanomaterials to demonstrate the road of nanomaterials towards industry. The engineering principles of the mass production and recent progress in the area of CNT purification and dispersion are described, as well as its bulk application for nanocomposites and energy storage. The environmental, health, and safety considerations of CNTs, and recent progress in CNT commercialization are also included. With the effort from the CNT industry during the past 10 years, the price of multi-walled CNTs have decreased from 45 000 to 100 $ kg(-1) and the productivity increased to several hundred tons per year for commercial applications in Li ion battery and nanocomposites. When the prices of CNTs decrease to 10 $ kg(-1) , their applications as composites and conductive fillers at a million ton scale can be anticipated, replacing conventional carbon black fillers. Compared with traditional bulk chemicals, the controllable synthesis and applications of CNTs on a million ton scale are still far from being achieved due to the challenges in production, purification, dispersion, and commercial application. The basic knowledge of growth mechanisms, efficient and controllable routes for CNT production, the environmental and safety issues, and the commercialization models are still inadequate. The gap between the basic scientific research and industrial development should be bridged by multidisciplinary research for the rapid growth of CNT nano-industry.

588 citations


Cited by
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Journal ArticleDOI
TL;DR: Two important future research directions are indicated and summarized, based on results published in the literature: the development of composite and nanostructured ES materials to overcome the major challenge posed by the low energy density.
Abstract: In this critical review, metal oxides-based materials for electrochemical supercapacitor (ES) electrodes are reviewed in detail together with a brief review of carbon materials and conducting polymers. Their advantages, disadvantages, and performance in ES electrodes are discussed through extensive analysis of the literature, and new trends in material development are also reviewed. Two important future research directions are indicated and summarized, based on results published in the literature: the development of composite and nanostructured ES materials to overcome the major challenge posed by the low energy density of ES (476 references).

7,642 citations

Journal ArticleDOI
TL;DR: In this article, a review of the key technological developments and scientific challenges for a broad range of Li-ion battery electrodes is presented, and the potential/capacity plots are used to compare many families of suitable materials.

5,057 citations

Journal ArticleDOI
01 Feb 2013-Science
TL;DR: Although not yet providing compelling mechanical strength or electrical or thermal conductivities for many applications, CNT yarns and sheets already have promising performance for applications including supercapacitors, actuators, and lightweight electromagnetic shields.
Abstract: Worldwide commercial interest in carbon nanotubes (CNTs) is reflected in a production capacity that presently exceeds several thousand tons per year. Currently, bulk CNT powders are incorporated in diverse commercial products ranging from rechargeable batteries, automotive parts, and sporting goods to boat hulls and water filters. Advances in CNT synthesis, purification, and chemical modification are enabling integration of CNTs in thin-film electronics and large-area coatings. Although not yet providing compelling mechanical strength or electrical or thermal conductivities for many applications, CNT yarns and sheets already have promising performance for applications including supercapacitors, actuators, and lightweight electromagnetic shields.

4,596 citations

Journal ArticleDOI
TL;DR: In this article, the pseudocapacitance properties of transition metal oxides have been investigated and a review of the most relevant pseudo-capacitive materials in aqueous and non-aqueous electrolytes is presented.
Abstract: Electrochemical energy storage technology is based on devices capable of exhibiting high energy density (batteries) or high power density (electrochemical capacitors). There is a growing need, for current and near-future applications, where both high energy and high power densities are required in the same material. Pseudocapacitance, a faradaic process involving surface or near surface redox reactions, offers a means of achieving high energy density at high charge–discharge rates. Here, we focus on the pseudocapacitive properties of transition metal oxides. First, we introduce pseudocapacitance and describe its electrochemical features. Then, we review the most relevant pseudocapacitive materials in aqueous and non-aqueous electrolytes. The major challenges for pseudocapacitive materials along with a future outlook are detailed at the end.

3,930 citations

Journal ArticleDOI
TL;DR: Electrospinning is a highly versatile method to process solutions or melts, mainly of polymers, into continuous fibers with diameters ranging from a few micrometers to a few nanometers, applicable to virtually every soluble or fusible polymer.
Abstract: Electrospinning is a highly versatile method to process solutions or melts, mainly of polymers, into continuous fibers with diameters ranging from a few micrometers to a few nanometers. This technique is applicable to virtually every soluble or fusible polymer. The polymers can be chemically modified and can also be tailored with additives ranging from simple carbon-black particles to complex species such as enzymes, viruses, and bacteria. Electrospinning appears to be straightforward, but is a rather intricate process that depends on a multitude of molecular, process, and technical parameters. The method provides access to entirely new materials, which may have complex chemical structures. Electrospinning is not only a focus of intense academic investigation; the technique is already being applied in many technological areas.

3,833 citations