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Abstract: Carbon nanomaterials, especially graphene and carbon nanotubes, are considered to be favorable alternatives to graphite‐based anodes in lithium‐ion batteries, owing to their high specific surface area, electrical conductivity, and excellent mechanical flexibility. However, the limited number of storage sites for lithium ions within the sp2‐carbon hexahedrons leads to the low storage capacity. Thus, rational structure design is essential for the preparation of high‐performance carbon‐based anode materials. Herein, we employed flexible single‐walled carbon nanotubes (SWCNTs) with ultrahigh electrical conductivity as a wrapper for 3D graphene foam (GF) by using a facile dip‐coating process to form a binary network structure. This structure, which offered high electrical conductivity, enlarged the electrode/electrolyte contact area, shortened the electron‐/ion‐transport pathways, and allowed for efficient utilization of the active material, which led to improved electrochemical performance. When used as an anode in lithium‐ion batteries, the SWCNT‐GF electrode delivered a specific capacity of 953 mA h g−1 at a current density of 0.1 A g−1 and a high reversible capacity of 606 mA h g−1 after 1000 cycles, with a capacity retention of 90 % over 1000 cycles at 1 A g−1 and 189 mA h g−1 after 2200 cycles at 5 A g−1. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) with copper(I) sulfide (Cu 2 S) anodes has been gaining significant attention because of their relatively high capacity and inherent safety. The highly reversible conversion of Cu/Na 2 S in charging process to pristine Cu 2 S is essential for its electrochemical properties. Here, we have prepared Cu 2 S/carbon nanotube (CNT) anode for SIBs, in which highly-conductive CNTs are employed as a catalyst to promote the reversible reaction kinetics of Cu 2 S anode. By using a combination of electrochemical and ex-situ X-ray diffraction analysis, we demonstrate that Cu 2 S/CNT anodes can be converted efficiently and reversibly in comparison with a pure Cu 2 S anode. CNTs have superior electron conductivity and high surface area, and are therefore used for balancing the poor electronic conductivity of Cu 2 S and discharged products, as well as physically inhibition of the dissolution of sodium polysulfide. Consequently, a partially reversible conversion reaction is enabled during the charging process. In this study, we are contributing to the design of conversion-type materials that feature reversible mechanisms, opening up new possibilities for materials design. • CNTs are used to promote the reversible reaction kinetics of the Cu 2 S anode for SIBs. • CNTs with superior electron conductivity are used for balancing the poor conductivity of Cu2S and discharged products. • CNTs can physically inhibit the dissolution of sodium polysulfide. • Cu 2 S@CNT anode shows long-term cycling stability. [ABSTRACT FROM AUTHOR]

Organolead halide perovskite solar cells (PSC) are arising as promising candidates for next-generation renewable energy conversion devices. Currently, inverted PSCs typically employ expensive organic semiconductor as electron transport material and thermally deposited metal as cathode (such as Ag, Au, or Al), which are incompatible with their large-scale production. Moreover, the use of metal cathode also limits the long-term device stability under normal operation conditions. Herein, a novel inverted PSC employs a SnO2-coated carbon nanotube (SnO2@CSCNT) film as cathode in both rigid and flexible substrates (substrate/NiO-perovskite/Al2O3-perovskite/SnO2@CSCNT-perovskite). Inverted PSCs with SnO2@CSCNT cathode exhibit considerable enhancement in photovoltaic performance in comparison with the devices without SnO2 coating owing to the significantly reduced charge recombination. As a result, a power conversion efficiency of 14.3% can be obtained on rigid substrates while the flexible ones achieve 10.5% efficiency. More importantly, SnO2@CSCNT-based inverted PSCs exhibit significantly improved stability compared to the standard inverted devices made with silver cathode, retaining over 88% of their original efficiencies after 550 h of full light soaking or thermal stress. The results indicate that SnO2@CSCNT is a promising cathode material for long-term device operation and pave the way toward realistic commercialization of flexible PSCs. [ABSTRACT FROM AUTHOR]

Flexible lithium-ion batteries are critical for the next-generation electronics. However, during the practical application, they may break under deformations such as twisting and cutting, causing their failure to work or even serious safety problems. A new family of all-solid-state and flexible aqueous lithium ion batteries that can self-heal after breaking has been created by designing aligned carbon nanotube sheets loaded with LiMn2O4 and LiTi2(PO4)3 nanoparticles on a self-healing polymer substrate as electrodes, and a new kind of lithium sulfate/sodium carboxymethylcellulose serves as both gel electrolyte and separator. The specific capacity, rate capability, and cycling performance can be well maintained after repeated cutting and self-healing. These self-healing batteries are demonstrated to be promising for wearable devices. [ABSTRACT FROM AUTHOR]

Owing to the high theoretical energy density of metal-air batteries, the aluminum-air battery has been proposed as a promising long-term power supply for electronics. However, the available energy density from the aluminum-air battery is far from that anticipated and is limited by current electrode materials. Herein we described the creation of a new family of all-solid-state fiber-shaped aluminum-air batteries with a specific capacity of 935 mAhg-1 and an energy density of 1168 Whkg-1. The synthesis of an electrode composed of cross-stacked aligned carbon-nanotube/silver-nanoparticle sheets contributes to the remarkable electrochemical performance. The fiber shape also provides the aluminum-air batteries with unique advantages; for example, they are flexible and stretchable and can be woven into a variety of textiles for large-scale applications. [ABSTRACT FROM AUTHOR]

A new family of aligned nitrogen‐doped core–sheath carbon nanotube films is synthesized by growing nitrogen‐doped graphene layers coaxially around carbon nanotubes. The films exhibit both high tensile strength and electrical conductivity, and they are developed as flexible and effective anodes for lithium ion batteries that display high specific capacities. The lithium ion battery stably works under bending and twisting. [ABSTRACT FROM AUTHOR]

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Energy storage devices, such as lithium-ion batteries and supercapacitors, are required for the modern electronics. However, the intrinsic characteristics of low power densities in batteries and low energy densities in supercapacitors have limited their applications. How to simultaneously realize high energy and power densities in one device remains a challenge. Herein a fiber-shaped hybrid energy-storage device (FESD) formed by twisting three carbon nanotube hybrid fibers demonstrates both high energy and power densities. For the FESD, the energy density (50 mWh cm−3 or 90 Wh kg−1) many times higher than for other forms of supercapacitors and approximately 3 times that of thin-film batteries; the power density (1 W cm−3 or 5970 W kg−1) is approximately 140 times of thin-film lithium-ion battery. The FESD is flexible, weaveable and wearable, which offers promising advantages in the modern electronics. [ABSTRACT FROM AUTHOR]

An aligned and laminated sulfur-absorbed mesoporous carbon/carbon nanotube (CNT) hybrid cathode has been developed for lithium-sulfur batteries with high performance. The mesoporous carbon acts as sulfur host and suppresses the diffusion of polysulfide, while the CNT network anchors the sulfur-absorbed mesoporous carbon particles, providing pathways for rapid electron transport, alleviating polysulfide migration and enabling a high flexibility. The resulting lithium-sulfur battery delivers a high capacity of 1226 mAh g−1 and achieves a capacity retention of 75 % after 100 cycles at 0.1 C. Moreover, a high capacity of nearly 900 mAh g−1 is obtained for 20 mg cm−2, which is the highest sulfur load to the best of our knowledge. More importantly, the aligned and laminated hybrid cathode endows the battery with high flexibility and its electrochemical performances are well maintained under bending and after being folded for 500 times. [ABSTRACT FROM AUTHOR]

The construction of lightweight, flexible and stretchable power systems for modern electronic devices without using elastic polymer substrates is critical but remains challenging. We have developed a new and general strategy to produce both freestanding, stretchable, and flexible supercapacitors and lithium-ion batteries with remarkable electrochemical properties by designing novel carbon nanotube fiber springs as electrodes. These springlike electrodes can be stretched by over 300 %. In addition, the supercapacitors and lithium-ion batteries have a flexible fiber shape that enables promising applications in electronic textiles. [ABSTRACT FROM AUTHOR]

A stretchable wire-shaped lithium-ion battery is produced from two aligned multi-walled carbon nanotube/lithium oxide composite yarns as the anode and cathode without extra current collectors and binders. The two composite yarns can be well paired to obtain a safe battery with superior electrochemical properties, such as energy densities of 27 Wh kg−1 or 17.7 mWh cm−3 and power densities of 880 W kg−1 or 0.56 W cm−3, which are an order of magnitude higher than the densities reported for lithium thin-film batteries. These wire-shaped batteries are flexible and light, and 97 % of their capacity was maintained after 1000 bending cycles. They are also very elastic as they are based on a modified spring structure, and 84 % of the capacity was maintained after stretching for 200 cycles at a strain of 100 %. Furthermore, these novel wire-shaped batteries have been woven into lightweight, flexible, and stretchable battery textiles, which reveals possible large-scale applications. [ABSTRACT FROM AUTHOR]

Superstretchy: A supercapacitor with high stretchability has been developed by wrapping two layers of sheets built of aligned carbon nanotubes, which serve as two electrodes, on an elastic fiber. The use of these sheets offers high flexibility, tensile strength, electrical conductivity, and mechanical and thermal stability. The supercapacitor shows and maintains a high specific capacitance after stretching for many cycles. [ABSTRACT FROM AUTHOR]

We describe a biosensor for phenolic compounds that is based on a glassy carbon electrode modified with tyrosinase immobilized on multiwalled carbon nanotubes (MWNTs). The MWNTs possess excellent inherent electrical conductivity which enhances the electron transfer rate and results in good electrochemical catalytic activity towards the reduction of benzoquinone produced by enzymatic reaction. The biosensor was characterized by cyclic voltammetry, and the experimental conditions were optimized. The cathodíc current is linearly related to the concentration of the phenols between 0.4 μM and 10 μM, and the detection limit is 0.2 μM. The method was applied to the determination of phenol in water samples. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: Novel hybrid nanomaterials with iron oxide nanoparticles incorporated in nitrogen-doped carbon nanotube have been synthesized with tunable structures by a ready chemical vapor deposition process. These hybrid nanotubes show promising electronic applications. [Copyright &y& Elsevier]

Inspired by the fantastic and fast-growingwearable electronicssuch as Google Glass and Apple iWatch, matchable lightweight and weaveableenergy storage systems are urgently demanded while remaining as abottleneck in the whole technology. Fiber-shaped energy storage devicesthat can be woven into electronic textiles may represent a generaland effective strategy to overcome the above difficulty. Here a coaxialfiber lithium-ion battery has been achieved by sequentially windingaligned carbon nanotube composite yarn cathode and anode onto a cottonfiber. Novel yarn structures are designed to enable a high performancewith a linear energy density of 0.75 mWh cm–1. Awearable energy storage textile is also produced with an areal energydensity of 4.5 mWh cm–2. [ABSTRACT FROM AUTHOR]

Abstract: Due to the unique structure and excellent properties, carbon nanotubes (CNTs) have been widely proposed as electrode materials. However, the CNTs typically appear in a format of networks in which charges have to hop through a lot of boundaries with low efficiency. Here we have described a pressing method to produce penetrated and aligned CNT films in which the generated charges can be rapidly separated and transported during the application as electrodes. As a demonstration, they were used as counter electrodes to fabricate dye-sensitized solar cell with an efficiency of ∼8.46%, which was higher than the conventional platinum electrode. [Copyright &y& Elsevier]