[Liu, Chang; Li, Feng; Ma, Lai-Peng; Cheng, Hui-Ming] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China.;Cheng, HM (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, 72 Wenhua Rd, Shenyang 110016, Peoples R China;cheng@imr.ac.cn

Advanced Materials for Energy Storage

Carbon materials have attracted intense interests as electrode materials for electrochemical capacitors, because of their high surface area, electrical conductivity, chemical stability and low cost. Activated carbons produced by different activation processes from various precursors are the most widely used electrodes. Recently, with the rapid growth of nanotechnology, nanostructured electrode materials, such as carbon nanotubes and template-synthesized porous carbons have been developed. Their unique electrical properties and well controlled pore sizes and structures facilitate fast ion and electron transportation. In order to further improve the power and energy densities of the capacitors, carbon-based composites combining electrical double layer capacitors (EDLC)-capacitance and pseudo-capacitance have been explored. They show not only enhanced capacitance, but as well good cyclability. In this review, recent progresses on carbon-based electrode materials are summarized, including activated carbons, carbon nanotubes, and template-synthesized porous carbons, in particular mesoporous carbons. Their advantages and disadvantages as electrochemical capacitors are discussed. At the end of this review, the future trends of electrochemical capacitors with high energy and power are proposed.

Carbon Materials for Chemical Capacitive Energy Storage

The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

Ultracapacitors: Why, How, and Where is the Technology

Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

In this paper, the use of nanostructured anode materials for rechargeable lithium-ion batteries (LIBs) is reviewed. Nanostructured materials such as nano-carbons, alloys, metal oxides, and metal sulfides/nitrides have been used as anodes for next-generation LIBs with high reversible capacity, fast power capability, good safety, and long cycle life. This is due to their relatively short mass and charge pathways, high transport rates of both lithium ions and electrons, and other extremely charming surface activities. In this review paper, the effect of the nanostructure on the electrochemical performance of these anodes is presented. Their synthesis processes, electrochemical properties, and electrode reaction mechanisms are also discussed. The major goals of this review are to give a broad overview of recent scientific researches and developments of anode materials using novel nanoscience and nanotechnology and to highlight new progresses in using these nanostructured materials to develop high-performance LIBs. Suggestions and outlooks on future research directions in this field are also given.

Recent developments in nanostructured anode materials for rechargeable lithium-ion batteries

A carbon nanofiber-based electrode, exhibiting a large accessible surface area (derived from the nanometer-sized fiber diameter), high carbon purity (without binder), relatively high electrical conductivity, structural integrity, thin web macromorphology, a large reversible capacity (ca. 450 mA h g–1), and a relatively linearly inclined voltage profile, is fabricated by nanofiber formation via electrospinning of a polymer solution and its subsequent thermal treatment. It is envisaged that these characteristics of this novel carbon material will make it an ideal candidate for the anode material of high-power lithium-ion batteries (where a high current is critically needed), owing to the highly reduced lithium-ion diffusion path within the active material.

Fabrication of electrospinning-derived carbon nanofiber webs for the anode material of lithium-ion secondary batteries

Polyacrylonitrile-based nanofibers—A state-of-the-art review

Currently, intrinsicproblems, such as their limited available amount of chargeand high cost, combined with their low effective specific sur-face areas, limit the practical usage of carbon nanotubes asthe electrode material in supercapacitors.Recently, we reported another route to fibrous carbon ma-terials (ca. 300 nm) that relies on an electrospinning step withsubsequent steam activation.

Self-Sustained Thin Webs Consisting of Porous Carbon Nanofibers for Supercapacitors via the Electrospinning of Polyacrylonitrile Solutions Containing Zinc Chloride**

Kap Seung Yang

Papers

Fabrication of electrospinning-derived carbon nanofiber webs for the anode material of lithium-ion secondary batteries

Polyacrylonitrile-based nanofibers—A state-of-the-art review

Self-Sustained Thin Webs Consisting of Porous Carbon Nanofibers for Supercapacitors via the Electrospinning of Polyacrylonitrile Solutions Containing Zinc Chloride**

Synthesis and Characterization of Porous Carbon Nanofibers with Hollow Cores Through the Thermal Treatment of Electrospun Copolymeric Nanofiber Webs

TiO2 nanoparticles loaded on graphene/carbon composite nanofibers by electrospinning for increased photocatalysis