Highly flexible porous carbon nanofibers (P-CNFs) were fabricated by electrospining technique combining with metal ion-assistant acid corrosion process. The resultant fibers display high conductivity and outstanding mechanical flexibility, whereas little change in their resistance can be observed under repeatedly bending, even to 180°. Further results indicate that the improved flexibility of P-CNFs can be due to the high graphitization degree caused by Co ions. In view of electrode materials for high-performance supercapacitors, this type of porous nanostructure and high graphitization degree could synergistically facilitate the electrolyte ion diffusion and electron transportation. In the three electrodes testing system, the resultant P-CNFs electrodes can exhibit a specific capacitance of 104.5 F g(-1) (0.2 A g(-1)), high rate capability (remain 56.5% at 10 A g(-1)), and capacitance retention of ∼94% after 2000 cycles. Furthermore, the assembled symmetric supercapacitors showed a high flexibility and can deliver an energy density of 3.22 Wh kg(-1) at power density of 600 W kg(-1). This work might open a way to improve the mechanical properties of carbon fibers and suggests that this type of freestanding P-CNFs be used as effective electrode materials for flexible all-carbon supercapacitors.

NiCo2S4@CoSx core/shell nanotube arrays have been successfully synthesized and used to optimize the capacitive performance of electrochemical supercapacitors.

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As a class of the efficacious photocatalysts for watersplitting, conjugated polymers (CPs) have drawn considerable attention in recent years. However, the unexpectedly fast charge recombination always constricts their further application, leading to poor photocatalytic behavior. Here, we report a series of dibenzothiophene-S,S-dioxide-based polymers with electron-property-dependent reactivity as well as their photocatalysis in hydrogen evolution. The results reveal that the introduction of a secondary acceptor unit into the repeating units of a CP skeleton is an effective method to enhance the photocatalytic hydrogen production activity, which is conducive to the separation and transport of photogenerated charge carriers. Therefore, the Pt-free B-SO and C 3 N 3 -SO photocatalysts in an A 1 −π−A 2 form exhibit a competitive hydrogen evolution rate (HER) of 778 and 1603 μmol g −1 h −1 under visible light, respectively. Notably, under the same conditions, the 3 wt % Pt-modified B-SO and C 3 N 3 -SO provide a satisfactory HER of 1253 and 2966 μmol g −1 h −1 , respectively. Our study proffered an effective strategy for enhancing the photocatalytic hydrogen evolution of CPs, which could be used for the design and optimization of other photocatalytic systems.

This study reports the preparation of 3D hierarchical carbon nanotube (CNT) @MnO2 core-shell nanostructures under the assistance of polypyrrole (PPy). The as-prepared CNT@PPy@MnO2 core-shell structures show a perfect coating of MnO2 on each CNT and, more importantly, a robust bush-like pseudocapacitive shell to effectively increase the specific surface area and enhance the ion accessibility. As expected, a high specific capacity of 490-530 F g(-1) has been achieved from CNT@PPy@MnO2 single electrodes. And about 98.5% of the capacity is retained after 1000 charge/discharge cycles at a current density of 5 A g(-1). Furthermore, the assembled asymmetric CNT@PPy@MnO2//AC capacitors show the maximum energy density of 38.42 W h kg(-1) (2.24 mW h cm(-3)) at a power density of 100 W kg(-1) (5.83 mW cm(-3)), and they maintain 59.52% of the initial value at 10,000 W kg(-1) (0.583 W cm(-3)). In addition, the assembled devices show high cycling stabilities (89.7% after 2000 cycles for asymmetric and 87.2% for symmetric), and a high bending stability (64.74% after 200 bending tests). This ability to obtain high energy densities at high power rates while maintaining high cycling stability demonstrates that this well-designed structure could be a promising electrode material for high-performance supercapacitors.

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In this work, high voltage and high performance 3 V asymmetric supercapacitors were obtained by combining a VN nanowire electrode with an ultra-high concentration “water in salt” electrolyte.