Search

Herein, we have developed a facile and effective approach for synthesizing a novel kind of porous nitrogen-doped carbon-coated MnO nanosphere. The porous Mn2O3 nanospheres are initially obtained by the calcination treatment of a coordination self-assembled aggregation precursor (referred to as Mn(OAc)2-C-8). Then, MnO@N-doped carbon composites (MnO@NCs) are obtained by the calcination of the Mn2O3 nanospheres coated with polydopamine (Mn2O3@PDA). The MnO@NCs are evaluated as an anode for lithium ion batteries (LIBs), which exhibit high specific capacity, stable cycling performance (1096.6 mA h g−1 after 100 cycles at 100 mA g−1) and high coulombic efficiency (about 99% over 100 cycles). The unique structure design and synergistic effect not only settle the challenges of low conductivity and poor cycling stability of transition metal oxides but also resolve the imperfection of inferior specific capacity of traditional graphite materials. Importantly, it may provide a commendable conception for developing new-fashioned anode materials to improve the lithium storage capability and electrochemical performance.

In this paper, we report a synthetic route for cobalt sulfides nanoparticles embedded in porous carbon fibers (Co9S8@C) by carbonizing polydopamine (PDA)-coated metal coordination polymers (MCPs) and subsequent sulfidation process. This material serves as an anode for lithium-ion batteries, which exhibits high capacity and good rate capability. At a rate of 0.1C, a high reversible capacity of 1565 mA h g−1 is being obtained. In addition, the battery maintains a stable reversible capacities of 606 mA h g−1 for 300 cycles at 1C. The improvement of lithium-storage performance is mainly attributed to the smart design of carbon-wrapped mesoporous Co9S8 fibers, which not only prevents aggregation and volume change of the Co9S8 particles, but also enables good conductivity, and thus enhances electrochemical stability.

Different from the conventional synthesis methods and substrates, we designed a brand new method for synthesizing amides with platinum nanowires as catalysts and tert -butylhydroperoxide (TBHP) as the oxidant. Influence of factors, such as the catalyst, solvents, and the reaction temperature, were studied to determine the optimal reaction conditions. In addition, we explored the substrate generality and observed excellent yields.

A novel type of transition bimetal–organic frameworks was described as a heterogeneous catalyst for the oxidative coupling of amines to imines under mild conditions, which was easily synthesized by the coordination assembly of manganese(II) and cobalt(II) with 1,3,5-benzenetricarboxylic acid (H3BTC) for the first time. The metal–organic framework material was characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, thermogravimetry and N2 sorption. As an environmentally benign heterogeneous catalyst, the catalytic ability of the metal–organic framework material was then detected to be excellent for the tert-butyl hydroperoxide (TBHP) promoted direct oxidative coupling of benzylamines to imines in excellent yields (up to 100%) in methanol for 3 h. More importantly, it could be recycled up to six runs, while still maintaining its high catalytic activity.

In this study, we describe a rapid and environmentally friendly synthesis of bare Co3O4 nanocrystals derived from Co(ii) oleate complexes by calcination treatment. When directly used as anode materials for lithium-ion batteries (LIBs), the as-prepared nanocrystals could deliver a high reversible capacity of 980 mA h g(-1) after 250 cycles at a current density of 100 mA g(-1) and excellent cycling performance, which may be beneficial to promote the further development of the next generation of lithium ion batteries. The synthetic route can offer great advantages for the flash preparation of other metal oxide nanocrystals for energy storage application.

A novel kind of Co-based metal–organic frameworks (MOFs) are firstly prepared by coordination assembly of Co(II) and 1,3,5-benzenetricarboxylic acid (H3BTC) through a hydrothermal route (referred to as Co-BTC MOF). Such Co-BTC MOF have a zigzag vermicular-like shape with a length of 126 nm and a width of 55 nm. Co-BTC MOFs without calcination treatment are applied as anode materials for lithium-ion batteries (LIBs) and show superior electrochemical performance, including high lithium storage capacity (1739 mA h g−1 in the first discharge process at a current density of 100 mA g−1), excellent coulombic efficiency (above 99% in the 199th cycle) and cycling performance (>750 mA h g−1 over 200 cycles) in the potential range of 0.01–3.0 V vs. Li/Li+. Such excellent electrochemical performance may be derived from the conjugated carboxylate moiety and the linker structure. More importantly, the facile approach may also be extended to other metal-based MOFs and the intriguing results show that nano-sized MOFs will be regarded as futuristic anode materials for advanced lithium storage.

Herein, we have designed graphene-coated porous cobalt oxide fibers (Co3O4@G) using coordination polymers as precursors through calcination followed by a subsequent self-assembly process. The graphene-coated porous cobalt oxide fiber nanostructures not only provide good conductivity, but also prevent the aggregation and volume change of the Co3O4 nanoparticles during lithium storage processes. When serving as anode materials in the lithium-ion batteries, the obtained Co3O4@G composites, exhibit remarkable electrochemical performances, including high specific capacity (∼1303.9 mA h g−1 at a current density of 0.2 A g−1), excellent cycling stability (1153 mA h g−1 retention after 80 cycles at a current density of 0.2 A g−1) and high rate capability.

In this manuscript, we demonstrated a facile route for the controllable design of “Fluorine (F)-doped carbon” (C/F)-treated TiO 2 hollow spheres with mesoporous shells (MHTO-C/F). The fabrication of this distinct mesoporous hollow structures and the C/F coating could effectively improve the electrolyte permeability and architectural stability, as well as electrical conductivity and lithium ion mobility. As anticipated, MHTO-C/F has several remarkable electrochemical properties, such as a high specific reversible capacity of 252 mA h g −1 , outstanding cycling stability of more than 210 mA h g −1 after 100 cycles at 0.5 C, and good rate performance of around 123 mA h g −1 at 5 C (1 C = 168 mA g −1 ). These properties are highly beneficial for lithium storage.

A novel type of transition bimetal–organic frameworks was described as a heterogeneous catalyst for the oxidative coupling of amines to imines under mild conditions, which was easily synthesized by the coordination assembly of manganese(II) and cobalt(II) with 1,3,5-benzenetricarboxylic acid (H3BTC) for the first time. The metal–organic framework material was characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, thermogravimetry and N2 sorption. As an environmentally benign heterogeneous catalyst, the catalytic ability of the metal–organic framework material was then detected to be excellent for the tert-butyl hydroperoxide (TBHP) promoted direct oxidative coupling of benzylamines to imines in excellent yields (up to 100%) in methanol for 3 h. More importantly, it could be recycled up to six runs, while still maintaining its high catalytic activity.

In this study, we report the design and synthesis of a silver nanowire-γ-Fe2 O3 coaxial nanocable architecture (Ag NWs@γ-Fe2 O3 nanocable) through mild oxidation of [Fe(CO)5 ] on the surface of silver nanowires followed by a calcination process. After optimization of the structural design, the Ag NWs@γ-Fe2 O3 nanocable could deliver superior lithium storage performance in terms of high reversible capacity, good rate performance, and excellent stability, such as a high reversible capacity of about 890 mA h g(-1) after 60 cycles at a current rate of 0.1 C (1.0 C=1005 mA g(-1) ). The reversible capacity remains as high as about 550 mA h g(-1) even at a high current rate of 2.0 C. This dramatic performance is mainly attributed to the smart coaxial design, which can not only alleviate the large volume change and prevent the aggregation of γ-Fe2 O3 nanoparticles, but also enables good conductivity and thus enhances fast charge transfer. The unique structural features of the Ag NWs@γ-Fe2 O3 nanocable represent a promising anode material in lithium-ion battery applications.

A simple and scalable coordination-derived method for the synthesis of porous Co3O4 hollow nanospheres is described here. The initially formed coordination-driven self-assembled aggregates (CDSAAs) could act as the precursor followed by calcination treatment. Then the porous hollow Co3O4 nanospheres are obtained, in which the primary Co3O4 nanoparticles are inter-dispersed. When the nanospheres are used as anode materials for lithium storage, they show excellent coulombic efficiency, high lithium storage capacity and superior cycling performance. In view of the facile synthesis and excellent electrochemical performance obtained, this protocol to fabricate special porous hollow frameworks could be further extended to other metal oxides and is expected to improve the practicality of superior cycle life anode materials with large volume excursions for the development of the next generation of LIBs.