Boosting Capacitive Deionization Performance of Commercial Carbon Fibers Cloth via Structural Regulation Based on Catalytic-Etching Effect

Monolithic carbon electrodes with robust mechanical integrity and porous architecture are highly desired for capacitive deionization but remain challenging.Owing to the excellent mechanical strength and electroconductivity,commercial carbon fibers cloth demonstrates great potential as high-performance electrodes for ions storage.Despite this,its direct application on capacitive deionization is rarely reported in terms of limited pore structure and natural hydrophobicity.Herein,a powerful metal-organic framework-engaged structural regulation strategy is developed to boost the desalination properties of carbon fibers.The obtained porous carbon fibers features hierarchical porous structure and hydrophilic surface providing abundant ions-accessible sites,and continuous graphitized carbon core ensuring rapid electrons transport.The catalytic-etching mechanism involving oxidation of Co and subsequent carbonthermal reduction is proposed and highly relies on annealing temperature and holding time.When directly evaluated as a current collector-free capacitive deionization electrode,the porous carbon fibers demonstrates much superior desalination capability than pristine carbon fibers,and remarkable cyclic stability up to 20 h with negligible degeneration.Particularly,the PCF-1000 showcases the highest areal salt adsorption capacity of 0.037 mg cm^(−2) among carbon microfibers.Moreover,monolithic porous carbon fibers-carbon nanotubes with increased active sites and good structural integrity by in-situ growth of carbon nanotubes are further fabricated to enhance the desalination performance(0.051 mg cm^(−2)).This work demonstrates the great potential of carbon fibers in constructing high-efficient and robust monolithic electrode for capacitive deionization.

Modified room temperature solid-state synthesis of yttria-stabilized zirconia(YSZ) nano-powders for solid oxide fuel cells

High-performance solid oxide fuel cell(SOFC) is in urgent need of high-quality electrolyte powders with high reactivity and chemical uniformity.Here,8 mol% Y_(2)O_(3) doped ZrO_(2)(YSZ) nano-powders were synthesized by an improved solid-state reaction method at ambient temperature,and were applied to the fabrication of SOFC electrolytes.YSZ nano-powders show average grain sizes of ^(2)0 nm and high dispersibility,which is comparable with or even better than some other chemical methods.Benefitting from their high reactivity,dense YSZ electrolytes(relative density of 97.9%) can be obtained at a relatively low sintering temperature of 1400℃.The optimized electrical conductivity reaches up to a high value of0.034 S/cm at 800 0C in air.The anode supported single cell with the construction of Ni-YSZ/YSZ/Sm_(0.2)Ce_(0.8)O_(2-δ)(SDC)/La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF) exhibits the peak power density of 0.827 W/cm^(2) at800℃ while taking wet H_(2) as fuels and ambient air as oxidants.

Fiber orientation effects on grinding characteristics and removal mechanism of 2.5D C_(f)/SiC composites

Carbon fiber reinforced silicon carbide(C_(f)/SiC)composites are widely used in aerospace for their excellent mechanical properties.However,the quality of the machined surface is poor and unpredictable due to the material heterogeneity induced by complex removal mechanism.To clarify the effects of fiber orientation on the grinding characteristics and removal mechanism,single grit scratch experiments under different fiber orientations are conducted and a three-phase numerical modelling method for 2.5D C_(f)/SiC composites is proposed.Three fiber cutting modes i.e.,transverse,normal and longitudinal,are defined by fiber orientation and three machining directions i.e.,MA(longitudinal and normal),MB(longitudinal and transverse)and MC(normal and transverse),are selected to investigate the effect of fiber orientation on grinding force and micro-morphology.Besides,a three-phase cutting model of 2.5D C_(f)/SiC composites considering the mechanical properties of the matrix,fiber and interface is developed.Corresponding simulations are performed to reveal the micro-mechanism of crack initiation and extension as well as the material removal mechanism under different fiber orientations.The results indicate that the scratching forces fluctuate periodically,and the order of mean forces is MA>MC>MB.Cracks tend to grow along the fiber axis,which results in the largest damage layer for transverse fibers and the smallest for longitudinal fibers.The removal modes of transverse fibers are worn,fracture and peel-off,in which normal fibers are pullout and outcrop and the longitudinal fibers are worn and push-off.Under the stable cutting condition,the change of contact area between fiber and grit leads to different removal modes of fiber in the same cutting mode,and the increase of contact area results in the aggravation of fiber fracture.

Pomegranate micro/nano hierarchical plasma structure for superior microwave absorption

Inspired by the pomegranate natural artful structure,pomegranate micro/nano hierarchical plasma configuration of Fe/Fe3C@graphitized carbon(FFC/pCL)was constructed based on the green sol-gel method and in-situ chemical vapor deposition(CVD)synthesis protocol.Pomegranate-like FFC/pCL successfully overcame the agglomeration phenomenon of magnetic nanoparticles with each seed of the pomegranate consisting of Fe/Fe_(3)C as cores and graphitized carbon layers as shells.The high-density arrangement of magnetic nanoparticles and the design of pomegranate-like heterostructures lead to enhanced plasmon resonance.Thus,the pomegranate-like FFC/pCL achieved a great electromagnetic wave(EMW)absorbing performance of 6.12 GHz wide band absorption at a low mass adding of only 16.7 wt.%.Such excellent EMW performance can be attributed to its unique pomegranate hierarchical plasma configuration with separated nanoscale iron cores,surface porous texture,and good carbon conductive network.This investigation provides a new paradigm for the development of magnetic/carbon based EMW absorbing materials by taking advantage of pomegranate hierarchical plasma configuration.