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Abstract: The carbon nanotube/polyaniline (CNT/PANI) composites have important potential applications as the electrodes in energy storage devices for their attractive electrochemical properties. In this work, we report a novel method to prepare the interesting paper-like CNT/PANI composites by using the CNT network as the template. Compared with the conventional brittle CNT/PANI composites, these paper-like composites were much thin and flexible. This work demonstrates a new approach, which may transform a brittle polymer into flexible films. Meanwhile, these film electrodes showed much superior electrochemical performance such as higher specific capacitance, lower internal resistivity, and more stability under different current loads. These paper-like composite electrodes have promising applications in new kinds of energy storage devices. [Copyright &y& Elsevier]

Abstract Ultrathin and cross-stacked carbon nanotube (CNT) films modified with hafnium oxide (HfO 2) by atomic layer deposition are employed as efficient polysulfide barriers for high performance Li-S batteries. A HfO 2 /CNT interlayer has an ultrathin, flexible structure with a thickness of 1.5 μm and an areal density of 0.087 mg cm−2, along with excellent wettability to electrolyte. The highly conductive CNT network and the catalytic surface adsorption of polysulfide species by HfO 2 significantly suppress the polysulfides shuttling phenomenon. With high sulfur loadings of up to 75 wt%, electrodes incorporating a HfO 2 /CNT interlayer show noticeable improvements in various electrochemical properties, including long-term cycling stability (721 mA h g−1 after 500 cycles at 1 C), high rate performance (800 mA h g−1 at 5 C), favorable anti-self-discharge capabilities, and suppression of Li anode corrosion. These results suggest a new and efficient polysulfide trapping material and a viable configuration for high-performance Li-S batteries. Graphical abstract An ultrathin HfO 2 /CNT interlayer is used as an efficient polysulfide barrier to improve the performance of Li-S batteries. Image 1 [ABSTRACT FROM AUTHOR]

Abstract Developing hybrid supercapacitor-battery energy storage devices for applications in electric vehicles is attractive because of their high energy density and short charge/discharge time. In this study, flexible MnO 2 nanoparticle-coated air-oxidized carbon nanotube (MnO 2 /aCNT) electrodes are fabricated by the in situ redox reaction of KMnO 4 and aCNTs at room temperature. The MnO 2 nanoparticles have diameters of ∼10 nm. There is a strong chemical interaction between the MnO 2 active material and aCNTs as a result of the Mn–O–C linkage. The flexible aCNT network can alleviate the strain from the MnO 2 volume change and maintain the electrode integrity during rapid charge/discharge. The aCNT framework also provides a continuous and rapid electron pathway and ensures uniform dispersion of the MnO 2 nanoparticles. The presence of MnO 2 nanoparticles provides short pathways for Li-ion diffusion and allows interfacial capacitive lithium storage for ultrafast and reversible lithium storage. We report the best high-current performance to date for MnO 2 /C electrodes, of 395.8 mA h g−1 at 10 A g−1, and 630.2 mA h g−1 after 150 cycles at 2 A g−1. The excellent electrochemical performance, combined with the capacitive dominating process of the electrode, will further the design of high-performance hybrid supercapacitor-battery energy storage devices. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Binder-free polymer encapsulated nano sulfur/super-aligned CNT (PVP@S-SACNT) composite electrode is developed via a solution-based method. In the composite structure, PVP not only facilitates better dispersion of SACNT bundles into a 3D continuous network, but also encapsulates the sulfur nanoparticles onto the SACNT network to ensure their tight electrical connection and prevent polysulfide dissolution. Combining the advantages of the high conductive and porous SACNT network and the PVP surface modification, the PVP@S-SACNT cathode exhibits excellent cyclic stability (initial capacity of 1303 mA h g −1 and 856 mA h g −1 after 200 cycles at 1 C) and high-rate performance (590 mA h g −1 at 20 C). Moreover, the PVP@S-SACNT composite presents excellent long-term capacity stability with a capacity decay of 0.052% per cycle during 1000 charge/discharge cycles at 2 C. With these appealing performances, the PVP@S-SACNT composite becomes a promising cathode material for the next-generation rechargeable batteries. [ABSTRACT FROM AUTHOR]

Abstract: Super-aligned multi-walled carbon nanotubes (MWCNTs), which had been produced in large-scale, were oxidized by H2O2 and HNO3. The surface defects and oxygen-containing functional groups introduced during the oxidizing process were characterized by Raman spectroscopy and X-ray photoelectron spectroscopy. The surface modification of MWCNTs improved the electrochemical properties. As a result, H2O2-treated and HNO3-treated MWCNTs displayed reversible capacities of 364mAh/g and 391mAh/g, respectively, after 80 galvanostatic cycles, corresponding to 143% and 154% improvements compared with pristine MWCNTs. The rate capability was also increased. At a current density of 3500mA/g, H2O2-treated and HNO3-treated MWCNTs exhibited reversible capacities of 66mAh/g and 156mAh/g, respectively. In contrast, pristine MWCNTs were only able to deliver 27mAh/g at this current density. [Copyright &y& Elsevier]

Abstract: Porous Li4Ti5O12 nanoclusters with high surface area are synthesized by a facile solution-based method followed by low-temperature calcination. The Li4Ti5O12 nanoclusters present the key characteristics needed to serve as high-performance negative electrodes for lithium ion batteries, including nano-sized dimension of the Li4Ti5O12 clusters (50–100 nm) for short ion and electron transfer path, and high surface area (142 m2 g−1) with mesoporosity (pore diameter 2–6 nm) for easy access to the electrolyte and efficient ion transport. Based on these characteristics, the Li4Ti5O12 electrode delivers an initial capacity of 173 mAh g−1 at the rate of 0.5 C, comparable to its theoretical capacity. Excellent cycling stability at high rates is achieved in the Li4Ti5O12 electrode, offering potential to serve as a negative electrode material for high rate lithium ion battery applications. [Copyright &y& Elsevier]

Abstract: Super-aligned carbon nanotube (CNT) film is a transparent conductive film composed of numerous parallel CNTs connected to each other by the van der Waals force. We have found that such films, attached to glass, can readily align liquid crystal molecules. A prototype liquid crystal display (LCD) using the film as the aligning layer has been fabricated. The on–off ratio of the as-prepared display cell is 85 when 24V is the applied voltage. Because of its high transparency, the film can simultaneously be used as a transparent electrode material, in place of expensive indium tin oxide. The resistance of the film makes it a suitable built-in heating layer, extending the working temperature range of LCDs. [Copyright &y& Elsevier]