摘要: Recent developments on the capacitive deionization (CDI) technique for water desalination are reviewed with a focus on carbon as the electrode material. The capacity and rate of salt adsorption and charge efficiency of various types of CDI cells, i.e. flow-by, membrane, flow-through-electrode, and flowing electrode cells are compared. Various carbon electrode materials for capacitor-type and battery-type cells are discussed. The flowing electrode cell with the short-circuit operation mode seems to be the most promising one for practical applications.
摘要: Because of their low price, excellent safety and energy storage performance, aqueous zinc-ion batteries (ZIBs) have great potential for use in the power grid and in wearable devices. However, the Zn anode of ZIBs is not stable, for example, Zn dendrite can be formed on the Zn anode accompanied by hydrogen evolution and side reactions, leading to its instability, which has been an obstacle to its use. Carbon nanomaterials have recently been used to improve the performance of Zn anodes due to their unique structure, excellent conductivity and good stability. This review summarizes this recent development for stabilizing zinc anodes. The carbon nanomaterials are used are as hosts, protective coating layers, electrolyte additives and modifiers in the separators to stabilize the Zn electrodes. The problems involved in doing this are presented, and some future developments are outlined.
摘要: Because of its high carbon content and easy graphitization, pitch is a promising precursor for carbon materials. To produce carbon materials with the desired performance, it is necessary to overcome the inherent shortcomings of pitch. For example, its complex composition and easy melting make it difficult to control the structure of the resulting carbon materials. Recently, researchers have proposed several methods to control the structure of carbon materials produced from pitch for energy storage applications. The latest advances in the structural design and preparation of pitch-based carbon materials for use in energy storage devices such as supercapacitors and alkali metal ion batteries are reviewed.
摘要: Carbon nanomaterials with a size of less than 10 nm, fluorescent carbon dots (CDs), have been extensively investigated, due to their excellent fluorescence tunability, good biocompatibility, wide range of precursors and low cost. Moreover, their simple preparation and excellent performance provide for a wide range of applications in the fields of optical sensing, energy storage, biomedical imaging, and white light-emitting diodes (WLEDs). A large number of solid-state photoluminescent CDs have recently been developed and used in WLEDs. The synthesis strategies of CDs are briefly summarized and their photoluminescence mechanisms are reviewed as well as the recent progress for their use in WLEDs. Finally, prospects for solving the current problems and challenges of CDs for WLEDs are briefly presented and discussed.
摘要: MXene is a revolutionary two-dimensional material that has a distinct layer structure and the chemical composition of transition metal carbides. It has special physicochemical characteristics including a large specific surface area, good electrical conductivity, excellent mechanical properties and photothermal behavior, which give it a valuable variety of applications. To endow it a broader range of applications, it is often composited with carbon-based materials. Therefore, MXene and MXene/carbon composites have attracted much attention in applications such as electronics, biosensors and biomedicine over recent years. In this review, the fabrication, modification and biomedical applications of MXene and MXene/carbon composites are introduced, focussing on their biomedical applications, such as biosensors, antibacterial materials, drug delivery, and the diagnosis and treatment of diseases.
摘要: The synthesis of high-rate and long-life anode materials for sodium ion batteries (SIBs) has attracted much attention. However, the slow kinetics and large increase in volume of the batteries remain major problems. Both metal-organic frameworks and MoS2 have shown properties suitable for SIBs, making research on their composite systems an attractive area of research. We report the formation of flower-like Co9S8/MoS2/C composites by a simultaneous vulcanization-carbonization process using MoCl5 as the Mo source and a 2-methylimidazole cobalt salt as the Co and C precursor at different temperatures（600, 700 and 800 °C）in sublimed sulfur. The effect of the heterojunction on the diffusion kinetics was analyzed using density functional theory. The results indicate that the electronic structure is different at the interface in the heterogeneous structure, exhibiting typical metallic properties and better electronic conductivity. In addition, the anode material Co9S8/MoS2/C synthesized at 700 °C had the most stable structure and best electrochemical performance of the three samples. Notably, the discharge capacity of Co9S8/MoS2/C-700 fully recovered from 368 to 571 mAh g−1 and then stabilized at 543 mAh g−1 when the current density was restored from 4 000 to 40 mA g−1. This work demonstrates the preparation of heterojunction materials for composite anode materials as a step to producing high-performance metal SIBs.
摘要: Zinc ion capacitors (ZICs) have been widely studied in recent years due to their high energy density, excellent rate capability, long cycling life and low cost. The incorporation of oxygen functional groups (OFGs) on the surface of the carbon-based cathodes is an effective strategy for improving the capacitive performance of aqueous ZICs. However, whether their presence helps improve the capacitance of ethanol (EtOH)-based ZICs has not been investigated. In this work, a combination of nitric acid oxidation and thermal treatment was used to regulate the OFGs on the activated surface of the carbon cathode. The optimized sample had a high specific capacitance of 195 F g−1 at 1 A g−1 using ZnCl2/EtOH as the electrolyte, i.e., a 56% increase compared to an unmodified cathode (125 F g−1). ZICs also shown excellent stability for more than 16 000 cycles at 3 A g−1, while maintaining 100% coulombic efficiency. This significantly improved performance is attributed to the presence of OFGs, especially carboxyl and ester groups, which provide abundant electrochemical active sites for redox reaction with the zinc ions. This study reports a significant improvement in the specific capacitance of carbon cathodes for commercial EtOH-based ZIC systems.
摘要: Next-generation consumer electronics require excellent thermal management. Graphene is a good choice because its thermal conductivity is 13 times that of copper. Single-, bi- and few-layer graphene (SLG, BLG, FLG) with large sp2 domains were grown by rapid thermal processing chemical vapor deposition (RTP-CVD) from CH4 and H2 using Ar as the diluting gas. The quality of graphene was investigated by Raman spectroscopy and TEM. To demonstrate the heat dissipation capability of RTP-CVD-grown graphene, a 2 TB solid state drive was used and the temperature was measured by a FLIR thermal camera. Results indicate that high thermal conductivity graphene was prepared by diluting the precursor gas with Ar. SLG was prepared at a growth temperature of 1 000 °C and a time of 25 min. A transition from FLG to high-quality BLG was observed at low H2 concentrations. Using SLG, there was a 5 °C lower temperature rise than using a commercial copper heat dissipator. The heat dissipation ability of SLG was approximately 200 times that of commercial copper heat dissipators.
摘要: A nanocomposite of zinc sulfide nanodots imbedded in honeycomb-like N-S co-doped carbon nanosheets (ZnS/NS-CN) was synthesized from waste biomass orange peel using ZnCl2 as the hard template and zinc source, and melamine and thiourea as the respective nitrogen and sulfur sources. When used as the anode material in Li-ion batteries, ZnS/NS-CN has a high reversible capacity (853.5 mAh g−1 at 0.1 A g−1 after 300 cycles), an excellent long-term cycling stability (70.1% capacity retention after 1 000 cycles at 5 A g−1) and an outstanding rate capability. Besides, a ZnS/NS-CN//LiNiCoMnO2 full cell tested at 0.5-4 V has an excellent battery performance (140.4 mAh g−1 at 0.2 C after 150 cycles with an energy density of 132.4 Wh kg−1).
摘要: A low-cost, green catalyst for nitrobenzene (NB) hydrogenation is needed for aniline production. We report the preparation of highly-dispersed Co particles supported on N-doped carbons by the hydrothermal treatment of glucose, followed by the pyrolysis of a mixture of urea, glucose hydrochar and cobalt nitrate in one-pot. The effect of the pyrolysis temperature on the microstructure of the catalysts was studied. Results indicated that the activity for NB hydrogenation was highly affected by the surface area, Co-loading level and Co-Nx coordination in the catalysts. Co@NCG-800 pyrolyzed at 800 °C with 10% Co in the precursor had extraordinary activity for NB hydrogenation, achieving full conversion and 99% aniline selectivity in isopropanol at 100 °C and 1 MPa H2 pressure for 2.5 h. NB conversion and aniline selectivity over the catalysts remained almost unchanged after six recycles, due to the strong coordination between the N- and Co-species. The reaction system showed not only a high NB activity but also a green and durable catalytic process, with easy operation, easy separation and catalyst reusability.
摘要: Carbon fiber/epoxy (CF/EP) composites are widely used in the aerospace industry, but their interlaminar properties and out-of-plane thermal conductivity are poor because of the lack of CF reinforcement in the interlaminar area. We prepared carbon nanotube/polyimide (CNT/PI) composite films and used them to improve the interlaminar fracture toughness (ILFT) and thermal conductivity of laminates of CF/EP and CNT/PI. Interleaving CNT/PI films with unidirectional CF/EP prepregs increased the mode I (the pre-cracked laminate failure is governed by peel forces) and mode II (the crack is propagated by shear stresses) ILFT of CF/EP laminates by 260% and 220%, respectively, which is attributed to the reinforcement effect of the CNTs and the plastic deformation of PI film. In addition, the out-of-plane thermal conductivity of the laminates is improved by introducing CNT/PI films because of their intrinsic high thermal conductivity and the continuous conductive network of CNTs. This toughening method provides an effective strategy for improving the thermal conductivity and mechanical properties of CF/EP laminates simultaneously.
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