Carbon Nanotubes Grown on the Carbon Fibers to Enhance the Photothermal Conversion toward Solar-Driven Applications.

Photothermal conversion is a directly, sustainable, and green path to use solar energy and the one of the most important keys is the photothermal conversion material. How to obtain the durable and effective material for photothermal conversion with low cost and facile preparation is still a great challenge. In this work, the carbon nanotubes (CNTs) are grown on the carbon fibers (CFs) via the catalysis of trapped Fe and Co. The absorption of the as-prepared CFs/CNTs illustrate the enhancement from the visible light to the near-infrared light range. The photothermal conversion characterization shows the grown CNTs promoting the higher surface temperature and the highest temperature reaches to about 325 °C under 10 sun irradiations. The water evaporation on the CFs/CNTs is measured 1.40 ± 0.03 kg·cm-2·h-1 under 1 sun irradiation and the water evaporation rate is also found depending on the irradiation density. The photothermal conversion applications and the water evaporation under natural irradiation also reveal the suitable candidate of the CFs/CNTs for photothermal conversion application. This work provides a facile path to obtain effective carbon-based materials for photothermal application.

A polyaniline-modified electrode surface for boosting the electrocatalysis towards the hydrogen evolution reaction and ethanol oxidation reaction.

Here, polyaniline (PANI) is reported loaded on carbon paper to modify the carbon paper-PANI-Pt electrode surface, tailoring the electrocatalytic capability towards the hydrogen evolution reaction and ethanol oxidation reaction. The reasons for the enhancement by the PANI layer are attributed to the hydrophilic electrode surface, uniform dispersion of Pt, and large electrochemical active surface.

Controlled Synthesis of Co@N-Doped Carbon by Pyrolysis of ZIF with 2-Aminobenzimidazole Ligand for Enhancing Oxygen Reduction Reaction and the Application in Zn-Air Battery.

The Co/N-doped carbon material, as an important electrocatalytic material, has been attracted intense interest in ORR and Zn-air battery. Here, we report an efficient Co@N-doped carbon catalyst (Co@N-C-1) obtained by pyrolysis of ZIF precursor with 2-aminobenzimidazole. The introduction of 2-aminobenzimidazole results in the formation of hierarchical meso/microporous structure of the as-prepared Co@N-C-1, effectively avoiding the aggregation of Co nanoparticles during pyrolysis and the higher N content, which contributes to enhance the ORR electrocatalytic activities. The obtained Co@N-C-1 exhibits remarkable ORR performance with a half-wave potential of 0.938 V vs RHE in alkaline media. As the air catalyst of zinc-air batteries, Co@N-C-1 displays 1.439 V of open-circuit voltage and 1413.3 Wh·kg-1 of energy density.

One-pot synthesis of hierarchical Co1-xS/NC@MoS2/C hollow nanofibers based on one-dimensional metal coordination polymers for enhanced lithium and sodium-ion storage.

Multicomponent metal sulfides have been recognized as promising anode materials for lithium/sodium-ion storage given their enticing theoretical capacities. However, the simplification of synthetic processes and the construction of heterogeneous interfaces of multimetal sulfides remain great challenges. Herein, a hierarchical 1T-MoS2/carbon nanosheet decorated Co1-xS/N-doped carbon (Co1-xS/NC@MoS2/C) hollow nanofiber was designed and constructed via a one-pot hydrothermal method using a cobalt-based coordination polymer nanofiber. This nanofiber can transform in-situ into conductive N-doped carbon hollow fibers embedded with active Co1-xS nanoparticles, enabling the epitaxial growth of MoS2 nanosheets. Consequently, the Co1-xS/NC@MoS2/C composites achieve exceptional lithium/sodium-ion storage performance. Compared to MoS2/C microspheres and Co1-xS/NC hollow nanofibers alone, the Co1-xS/NC@MoS2/C hollow nanofibers deliver higher discharge capacities (1085.9 mAh g-1 for lithium-ion batteries (LIBs) and 748.5 mAh g-1 for sodium-ion batteries (SIBs) at 100 mA g-1), better capacity retention (910 mAh g-1 for LIBs and 636.5 mAh g-1 for SIBs after 150 cycles at 100 mA g-1), and increased cycling stability (407.2 mAh g-1 after 1000 cycles for SIBs at 1000 mA g-1). Furthermore, the kinetic analysis shows that the lithium/sodium-ion storage processes of the Co1-xS/NC@MoS2/C electrode are mainly controlled by pseudocapacitance behavior. The excellent electrochemical properties can thus be ascribed to the synergy of the MoS2/C nanosheets with the enlarged interlayer spacing, good conductivity of the carbon layers, and the Co1-xS nanoparticles embedded in the hollow nanofibers with extensive reaction sites.

A high-rate and long-life organic-oxygen battery.

Alkali metal-oxygen batteries promise high gravimetric energy densities but suffer from low rate capability, poor cycle life and safety hazards associated with metal anodes. Here we describe a safe, high-rate and long-life oxygen battery that exploits a potassium biphenyl complex anode and a dimethylsulfoxide-mediated potassium superoxide cathode. The proposed potassium biphenyl complex-oxygen battery exhibits an unprecedented cycle life (3,000 cycles) with a superior average coulombic efficiency of more than 99.84% at a high current density of 4.0 mA cm-2. We further reduce the redox potential of biphenyl by adding the electron-donating methyl group to the benzene ring, which successfully achieved a redox potential of 0.14 V versus K/K+. This demonstrates the direction and opportunities to further improve the cell voltage and energy density of the alkali-metal organic-oxygen batteries.