Flexible fiber‐shaped supercapacitors have shown great potential in portable and wearable electronics. However, small specific capacitance and low operating voltage limit the practical application of fiber‐shaped supercapacitors in high energy density devices. Herein, direct growth of ultrathin MnO2 nanosheet arrays on conductive carbon fibers with robust adhesion is exhibited, which exhibit a high specific capacitance of 634.5 F g−1 at a current density of 2.5 A g−1 and possess superior cycle stability. When MnO2 nanosheet arrays on carbon fibers and graphene on carbon fibers are used as a positive electrode and a negative electrode, respectively, in an all‐solid‐state asymmetric supercapacitor (ASC), the ASC displays a high specific capacitance of 87.1 F g−1 and an exceptional energy density of 27.2 Wh kg−1. In addition, its capacitance retention reaches 95.2% over 3000 cycles, representing the excellent cyclic ability. The flexibility and mechanical stability of these ASCs are highlighted by the negligible degradation of their electrochemical performance even under severely bending states. Impressively, as‐prepared fiber‐shaped ASCs could successfully power a photodetector based on CdS nanowires without applying any external bias voltage. The excellent performance of all‐solid‐state ASCs opens up new opportunity for development of wearable and self‐powered nanodevices in near future.

are widely used to trap LiPSs via N-Li + interaction, [4,[26][27][28] meanwhile B doping is demonstrated to improve the performance of S/carbon cathode in Li-S batteries due to the strong interaction between PS anions and positively polarized boron in the porous carbon. [29] Despite the fact that heteroatom doping enhances PSs trapping in the cathodes, the trapping efficiency is still limited due to constrained surface area and low doping ratio. In addition, the poor order and broad size distribution of pores in amorphous porous carbons have become major impediment to uniform sulfur distribution and redeposition. In order to get high doping ratio while ensuring high surface area and ordered pore structure for regular sulfur distribution, Tarascon and co-workers pioneered the use of metal-organic frameworks (MOFs) as host materials for sulfur storage, taking advantage of the weak binding between the PSs and the oxygenated framework. [30] Moreover, Zheng et al. [31] and Zhou et al. [32] also reported the Lewis acid-base interactions between PSs and MOFs, which helped decreasing shuttle effect. Nevertheless, the utilization of MOFs is still limited by their poor thermal stability and heavy metal sites, which increase the density of host and thus decrease the energy density of batteries. Recently, Liao et al. proposed utilization of N-doped covalent organic framework (COF) (CTF-1), an organic porous material with low density, small pore size, and large surface area, as host material for sulfur storage. [33] However, this N-doped COF shows only moderate PSs trapping efficiency due to lack of strong interaction between PSs and N-rich pore surface. Considering COFs are porous materials that allow precise control of pore size and surface, as well as homogeneous impregnation of active species in the pores, there is great opportunity to rationally design effective COFs as hosts to store sulfur and fully confine the mobile redox PS species. Although, Lee and co-workers have recently adopted the composite structure of microporous COF-1 grown on mesoporous carbon nanotube as a new interlayer for chemical trapping of PSs in Li-S batteries, the introduction of carbon nanotubes can give rise to complexity to fully probe the electrochemical properties of COFs. [34] Till now, the positive B and negative O double doped boronate ester COFs have never been used as sulfur hosts in Li-S batteries, which is a distinctly different conception from interlayer use.Here, we suggest using boronate ester COFs as the improved trapping matrices for enhanced adsorption of LiPSs. The high density and uniform distribution of positively polarized B and negatively polarized O within the pores guarantee simultaneous adsorption of S x 2− and Li + in soluble LiPSs and thus render sulfur redeposition more uniform. As a result, this new host shows unprecedentedly strong adsorption ability and hence efficiently traps LiPSs within the cathodes. Such unique feature distinguishes boronate ester COF system from other N-doped As one of the most promising energy...

A redox active pyridine based covalent organic framework was synthesized and used as an electrode in faradaic supercapacitors. The pyridine units in the DAP-COF undergo a reversible redox reaction, leading to an increase in specific capacitance relative to both its electroactive monomer and a COF lacking redox-active groups.

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In the present work, orienting to practicality and functionality beyond original fundamental simulation, we succeeded in fabricating superamphiphobic surfaces, which are super-repellent both to water and oil, upon common engineering metals (zinc, aluminum, iron, and nickel) and their alloys (Zn-Fe alloy and brass) by taking advantage of an electrochemical reaction in perfluorocarboxylic acid solutions. Via control over the chain length, concentration of perfluorocarboxylic acid, and the process time, textured rough structures on different substrates were achieved. The prepared surfaces show superamphiphobicity due to the synergistic effect of their special surface compositions and microscopic structures.

Wurtzite CuInS 2 -ZnS heterostructured nanorods are synthesized via a seed-assisted synthetic route. Cu 1.94 S-ZnS heterostructured nanorods are transformed into CuInS 2 -ZnS by reacting with indium ions to convert copper sulfide to wurtzite CuInS 2 . The shapes of the CuInS 2 -ZnS heterostructured nanorods can be tuned from burning torch-like to longer rod-like by varying the concentration of added indium.Dye-sensitized solar cells (DSSCs) using these heterostructured nanocrystals as counter electrodes had a power conversion efficiency (7.5%) superior to DSSCs made with conventional platinum electrode (7.1%) under the same device configuration.Dye-sensitized solar cells (DSSCs) are among the most promising photovoltaic devices for light-to-energy conversion with a relatively high efficiency. 1 Among different constitution components, the counter electrode is one of the most important parts in DSSCs, and platinum (Pt) is most commonly used. Unfortunately, Pt is relatively scarce and expensive, which creates a big obstacle for scale-up application of DSSC devices. 2 Therefore, lower-cost alternatives for counter electrodes in DSSCs are being sought.Generally, the counter electrode accomplishes two critical functions: it collects the electrons owing from the external circuit and regenerates the hole scavenger by catalyzing the reduction of I 3 À to I À . 3 Several previous reports have adopted electrically conductive materials for counter electrodes of DSSCs, including graphite, 4 carbon black, 2 carbon nanotubes, 5 and conducting polymers. 6 The efficiencies of these devices have generally been low, below 5%, because these materials have poor catalytic activity toward I 3 À /I À conversion. Very recently, alternative inorganic compounds, such as metal suldes, 7-9 metal oxides, 10 metal nitrides 11 and metal carbides, 12 have been studied as counter electrodes in DSSCs. In addition to a rather high electrical conductivity, these materials, especially CuZnSnS 4 , 7 have exhibited high catalytic activity toward I 3 À /I À pairs, and have been used to achieve device efficiencies comparable to DSSCs with Pt counter electrodes. However, current investigation on the counter electrodes is mainly focused on single chemical compounds of the simple

A novel type of inorganic hybridized ultrathin film consisting of Preyssler-type polyoxometalates K(14)[Na(H(2)O)P(5)W(30)O(110)] (Na-POMs) and CdSe@CdS nanoparticles (NPs) was prepared on the solid substrates by a layer-by-layer assembly technique. The film exhibits reversible fluorescence switching behavior under control of irradiation with either UV light or visible light, which is ascribed to the selective occurrence of fluorescence resonance energy transfer between luminescent NPs and different states of photochromic Na-POMs.