Hui Zhang

Bio: Hui Zhang is an academic researcher from Donghua University. The author has contributed to research in topics: Epoxy & Ceramic. The author has an hindex of 11, co-authored 43 publications receiving 415 citations.

Critical insight: Challenges and requirements of fibre electrodes for wearable electrochemical energy storage

Abstract: This perspective seeks to provide some critical insights on the challenges facing the development and adoption of fibre (yarn)-based energy storage electrodes in possible future applications of smart textiles. Attention has been given to five major points, viz. the property requirements, the associated characterization techniques, the metrics of quantifying performance, the associated materials and the goals of innovation. Beyond these points, concise conclusions consisting of recommendations have been drawn in each section. The work is intended to guide and stimulate researchers towards an effective and efficient roadmap to obtain the right and best product on the new prospective and exciting market.

Fe/Fe3C nanoparticle-decorated N-doped carbon nanofibers for improving the nitrogen selectivity of electrocatalytic nitrate reduction

Abstract: Nanoscale zero-valent iron has been considered to be the most promising electrocatalyst for denitrification due to its abundant resources, low price and non-toxicity. Nevertheless, the low utilization of active ingredients, inferior removal capacities (mg N g−1 Fe), and poor nitrogen selectivity are still major challenges during practical nitrate reduction. Herein, we have synthesized a one-dimensional architecture with homogeneously distributed Fe/Fe3C nanoparticles immobilized in a monodispersed carbonaceous matrix, embedded in ultra-high N-doped carbon nanofibers (Fe/Fe3C-NCNF) via a simple electrospinning strategy followed by confined reduction under a H2 atmosphere. The as-prepared Fe/Fe3C-NCNF nanostructure features well-dispersed Fe/Fe3C nanoparticles, confined reactive spaces, an interconnected nanofiber framework, and rich nitrogen doping sites, which are beneficial for integrating the synergistic catalytic effect of Fe and Fe3C, providing high-reactivity sites, boosting electron transfer, enlarging the catalyst–electrolyte interface and enhancing the surface adsorption capacity. The results reveal ultra-high nitrogen selectivity of 95% within 6 h and nearly 100% in 12 h, which are superior to other reported catalysts, and a maximum removal capacity of 2928.42 mg N g−1 Fe can be achieved, greatly improving the utilization of active ingredients. In addition, the catalysis material also shows good catalysis stability due to its structural features. The results of this study provide broad potential for the further development of iron-based functional nanostructures for electrocatalytic denitrification.

Simultaneously improving mode I and mode II fracture toughness of the carbon fiber/epoxy composite laminates via interleaved with uniformly aligned PES fiber webs

Abstract: In this work, a uniformly aligned polyethersulfone (PES) fiber web was designed and fabricated by the melt-spinning PES yarns. Such fiber web was adopted as an interleave to simultaneously improve both mode I and mode II fracture toughness of the carbon fiber/epoxy composite, addressing the issue of transforming the thermoplastic component into a well-controlled uniform and ordered phase structure without being influenced by the liquid forming process. The dissolution behaviors of the PES filaments in the epoxy resin were studied by the optical microscopy with a hot stage. The results indicated that the PES filaments were not dissolvable at the temperature of the resin infusion process, but could be dissolved during the curing process of the epoxy resin in a well controllable way and period. Both the mode I and mode II interlaminar fracture toughness of the composites were investigated as a function of areal densities of the PES fiber webs (7.3, 14.7, 21.2 and 28.3 gsm) carefully. A maximum enhancement up to 120% and 68.8% on mode I and II fracture toughness, respectively was obtained with the introduction of the 28.3 gsm-PES fiber web compared to the laminates without interleaves. Analysis of the fracture surfaces of the laminates elucidated that the distinctive improvement of the interlaminar fracture toughness could be attributed to the characteristic interlaminar structures induced from the phase separation of PES in epoxy resin. Moreover, the interleaved laminates displayed an increase of 18.2% and 43.8% for the interlaminar shear strength (ILLS) and compression-after-impact (CAI) properties, respectably. The tensile and flexural properties of the composite were thereafter explored which indicated slightly enhancement on the strengths.

Enhancing the Mechanical and Thermal Properties of Epoxy Resin via Blending with Thermoplastic Polysulfone

Abstract: Efficient enhancement of the toughness of epoxy resins has been a bottleneck for expanding their suitability for advanced applications. Here, polysulfone (PSF) was adopted to toughen and modify the epoxy. The influences of PSF on the mechanical and thermal properties of the epoxy resin were systematically studied by optical microscopy, Fourier transform infrared spectrometer (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analyzer (TG), dynamic mechanical thermal analyzer (DMA), mechanical tests and scanning electron microscope (SEM). The dissolution experimental results showed that PSF presents a good compatibility with the epoxy resin and could be well dissolved under controlled conditions. The introduction of PSF was found to promote the curing reaction of the epoxy resin without participating in the curing reaction and changing the curing mechanism as revealed by the FT-IR and DSC studies. The mechanical properties of PSF/epoxy resin blends showed that the fracture toughness and impact strength were significantly improved, which could be attributed to the bicontinuous phase structure of PSF/epoxy blends. Representative phase structures resulted from the reaction induced phase separation process were clearly observed in the PSF/epoxy blends during the curing process of epoxy resin, which presented dispersed particles, bicontinuous and phase inverted structures with the increase of the PSF content. Our work further confirmed that the thermal stability of the PSF/epoxy blends was slightly increased compared to that of the pure epoxy resin, mainly due to the good heat resistance of the PSF component.

Preparation of High-Performance Carbon Fiber-Reinforced Epoxy Composites by Compression Resin Transfer Molding.

Abstract: To satisfy the light weight requirements of vehicles owing to the aggravation of environmental pollution, carbon-fiber (CF)-reinforced epoxy composites have been chosen as a substitute for traditional metal counterparts. Since the current processing methods such as resin transfer molding (RTM) and compression molding (CM) have many limitations, an integrated and optimal molding method needs to be developed. Herein, we prepared high-performance composites by an optimized molding method, namely compression resin transfer molding (CRTM), which combines the traditional RTM and CM selectively and comprehensively. Differential scanning calorimetry (DSC) and rotational rheometry were performed to optimize the molding parameters of CRTM. In addition, metallurgical microscopy test and mechanical tests were performed to evaluate the applicability of CRTM. The experimental results showed that the composites prepared by CRTM displayed superior mechanical properties than those of the composites prepared by RTM and CM. The composite prepared by CRTM showed up to 42.9%, 41.2%, 77.3%, and 5.3% increases in tensile strength, bending strength, interlaminar shear strength, and volume fraction, respectively, of the composites prepared by RTM. Meanwhile, the porosity decreased by 45.2 %.

Nanocellulose: From Fundamentals to Advanced Applications

Abstract: Over the past few years, nanocellulose (NC), cellulose in the form of nanostructures, has been proved to be one of the most prominent green materials of modern times. NC materials have gained growing interests owing to their attractive and excellent characteristics such as abundance, high aspect ratio, better mechanical properties, renewability, and biocompatibility. The abundant hydroxyl functional groups allow a wide range of functionalizations via chemical reactions, leading to developing various materials with tunable features. In this review, recent advances in the preparation, modification, and emerging application of nanocellulose, especially cellulose nanocrystals (CNCs), are described and discussed based on the analysis of the latest investigations (particularly for the reports of the past 3 years). We start with a concise background of cellulose, its structural organization as well as the nomenclature of cellulose nanomaterials for beginners in this field. Then, different experimental procedures for the production of nanocelluloses, their properties, and functionalization approaches were elaborated. Furthermore, a number of recent and emerging uses of nanocellulose in nanocomposites, Pickering emulsifiers, wood adhesives, wastewater treatment, as well as in new evolving biomedical applications are presented. Finally, the challenges and opportunities of NC-based emerging materials are discussed.

Multifunctional Flexible Electromagnetic Interference Shielding Silver Nanowires/Cellulose Films with Excellent Thermal Management and Joule Heating Performances.

Abstract: Flexible electromagnetic interference (EMI) shielding materials with excellent thermal conductivities and Joule heating performances are of urgent demand in the communication industry, artificial intelligence, and wearable electronics. In this work, highly conductive silver nanowires (AgNWs) were prepared using the polyol method. Cellulose sheets were then prepared by dissolving natural cotton in a green and efficient NaOH/urea aqueous solution. Finally, multifunctional flexible EMI shielding AgNWs/cellulose films were fabricated based on vacuum-assisted filtration and hot-pressing. AgNWs are evenly embedded in the inner cellulose matrix and overlap with each other to form a 3D network. AgNWs/cellulose films, with a thickness of 44.5 μm, obtain the superior EMI shielding effectiveness of 101 dB, which is the highest value ever reported for shielding materials with the same thickness. In addition, AgNWs/cellulose films present excellent tensile strength (60.7 MPa) and tensile modulus (3.35 GPa), ultrahigh electrical conductivity (σ, 5571 S/cm), and excellent in-plane thermal conductivity coefficient (λ∥, 10.55 W/mK), which can effectively dissipate the heat accumulation. Interestingly, AgNWs/cellulose films also show outstanding Joule heating performances, good stability, and sensitive temperature response at driving voltages, absolutely safe for the human body. Therefore, our fabricated multifunctional flexible AgNWs/cellulose films have broad prospects in the fields of EMI shielding and protection of outdoor large-scale power transformers and wearable electronics.