Hierarchical multi-yolk-shell copper oxide@copper-1, 3, 5-benzenetricarboxylate as an ultrastable anode for lithium ion batteries.

The capacity attenuation of transition metal oxides (TMOs) and metal-organic frameworks (MOFs) is the obstacle for practical application in lithium ion batteries, due to the extensive volume variation upon charge/discharge cycles. Herein, a hierarchical composite material with copper oxide (CuO) multi-yolks and copper-1, 3, 5-benzenetricarboxylate (Cu-BTC) shell is synthesized by a facile method to study the effect of the hierarchical structure on the electrochemical performance. The porosity and pore volume of CuO@Cu-BTC composites are optimized to buffer the volume change and facilitate the infiltration of electrolytes by altering reaction conditions. The CuO@Cu-BTC (20 h) with the largest surface area and pore volume delivers an excellent reversible capacity of 780.7 mAh g-1 at 200 mA g-1 after 100 cycles, and ultrastable long-term performance with a specific capacity of 569 mAh g-1 at a current density of 1000 mA g-1 after 900 cycles. The corresponding full battery shows moderate capacity retention from 149.4 to 125.8 mAh g-1 after 70 cycles, with a specific capacity retention of 84.2%, based on the mass of lithium iron phosphate (LiFePO4) at 0.2 C (1 C = 170 mA g-1). This strategy applies copper oxide as the metal source of the coordination compound, as well as the internal yolks, which can be extended to the in-situ construction of other hierarchical composites, providing a new avenue for practical application of TMOs and MOFs as anode materials.

SnO x /graphene anode material with multiple oxidation states for high-performance Li-ion batteries.

Tin and its oxides are promising anode materials owing to their high theoretical capacity, rich resource, and environmental benignity. To achieve low cost and green synthesis, a facile synthetic route of SnO x /graphene composites is proposed, using a simple galvanic replacement method to quickly obtain abundant foamed tin as raw material and ball milling method to realize a mechanochemical reaction between SnO x (0 ≤ x ≤ 2) and graphene. Under different annealing conditions, the foamed tin is converted to tin oxides with multiple oxidation states (Sn3O4, SnO, and SnO2). These unique components can greatly affect the electrochemical performance of the electrode in LIBs. The as-prepared electrode (SnO x -300/G) obtained by annealing foamed tin at 300 °C for 4 h and combining SnO x powders with graphene via ball milling shows great cycling stability, retaining a high capacity of 786 mA h g-1 at 0.1 A g-1 after 150 cycles, and its initial Coulombic efficiency can reach 84.03%. Thus, this facile synthesis can provide an environmentally friendly route for commercial production of high-performance energy storage materials.

Diblock copolymers directing construction of hierarchically porous metal-organic frameworks for enhanced-performance supercapacitors.

A rationally designed strategy is developed to synthesize hierarchically porous Fe-based metal-organic frameworks (P-Fe-MOF) via solution-based self-assembly of diblock copolymers. The well-chosen amphiphilic diblock copolymers (BCP) of polystyrene-block-poly(acrylic acid) (PS-b-PAA) exhibits outstanding tolerance capability of rigorous conditions (e.g. strong acidity or basicity, high temperature and pressure), steering the peripheral crystallization of Fe-based MOF by anchoring ferric ions with outer PAA block. Importantly, the introduction of BCP endows MOF materials with additional mesopores (∼40 nm) penetrating whole crystals, along with their inherent micropores and introduced macropores. The unique hierarchically porous architecture contributes to fast charge transport and electrolyte ion diffusion, and thus promotes their redox reaction kinetics processes. Accordingly, the resultant P-Fe-MOF material as a new electrode material for supercapacitors delivers the unprecedented highest specific capacitance up to 78.3 mAh g-1 at a current density of 1 A g-1, which is 9.8 times than that of Fe-based MOF/carbon nanotubes composite electrode reported previously. This study may inspire new design of porous metal coordination polymers and advanced electrode materials for energy storage and conversion field.

The protective effects of different compatibility proportions of the couplet medicines for Astragali Radix and Angelica sinensis Radix on myocardial infarction injury.

Context: Astragali Radix (AR) and Angelica sinensis Radix (ASR) combinations are used to treat cardiovascular disorders.Objectives: This study investigates the protective effects of different compatibility proportions of AR and ASR on cardiac dysfunction in a C57BL/6 mouse model of myocardial infarction (MI).Materials and methods: MI mice were induced by ligation of the left coronary artery and divided into six groups: sham, vehicle, 10 mg/kg/d simvastatin and combinations of AR and ASR at different ratios, including 1:1 (AR 2.5 g/kg + ASR 2.5 g/kg), 3:1 (AR 3.75 g/kg + ASR 1.25 g/kg) and 5:1 (AR 4.17 g/kg + ASR 0.83 g/kg). Both AR-ASR combinations and simvastatin were dissolved in saline solution and given daily by gavage. The left ventricle function, infarct size, heart tissue injury, apoptosis of cardiomyocytes, leukocyte infiltrates, capillary density and expression of cleaved caspase-3, cleaved caspase-9, Bcl-2, Bax, Bad, IL-1ß, IL-6, VEGF, p-Akt and p-eNOS were analysed.Results: Different combinations of AR and ASR improve cardiac function and reduce infarct size (61.15% vs. 39.3%, 42.65% and 45.5%) and tissue injury through different mechanisms. When AR was combined with ASR at ratio of 1:1, the inflammation and cardiomyocyte apoptosis were suppressed (p < 0.05, p < 0.01). The combination ratio of 3:1 exerted effect in promoting angiogensis (p < 0.05). In the combination of AR and ASR at 5:1 ratio, angiogenesis was significantly improved (p < 0.01) and the apoptosis was inhibited (p < 0.05).Conclusions: Our results reflect the regulation of multiple targets and links in herb pairs and provide an important basis for the use of AR and ASR combinations in the treatment of MI.

Few-Layer MoS2 Nanosheets Encapsulated in N-Doped Carbon Hollow Spheres as Long-Life Anode Materials for Lithium-Ion Batteries.

Two-dimensional molybdenum disulfide (MoS2 ) has been recognized as a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity, but its rapid capacity decay owing to poor conductivity, structure pulverization, and polysulfide dissolution presents significant challenges in practical applications. Herein, triple-layered hollow spheres in which MoS2 nanosheets are fully encapsulated between inner carbon and outer nitrogen-doped carbon (NC) were fabricated. Such an architecture provides high conductivity and efficient lithium-ion transfer. Moreover, the NC shell prevents aggregation and exfoliation of MoS2 nanosheets and thus maintains the integrity of the nanostructure during the charge/discharge process. As anode materials for LIBs, the C@MoS2 @NC hollow spheres deliver a high reversible capacity (747 mA h g-1 after 100 cycles at 100 mA g-1 ) and excellent long-cycle performance (650 mA h g-1 after 1000 cycles at 1.0 A g-1 ), which confirm its potential for high-performance LIBs.

One-Step In Situ Self-Assembly of Cypress Leaf-Like Cu(OH)2 Nanostructure/Graphene Nanosheets Composite with Excellent Cycling Stability for Supercapacitors.

Transition metal hydroxides and graphene composite holds great promise to be the next generation of high performance electrode material for energy storage applications. Here we fabricate the cypress leaf-like Cu(OH)2 nanostructure/graphene nanosheets composite through one-step in situ synthesis process, employed as a new type of electrode material for high efficiency electrochemical energy storage in supercapacitors. A solution-based two-electrode system is applied to synthesize Cu(OH)2/graphene hybrid nanostructure, where anodic graphene nanosheets firmly anchor cathodic Cu(OH)2 nanostructure due to the electrostatic interaction. The in situ self-assembly of Cu(OH)2/graphene ensures good structural robustness and the cypress leaf-like Cu(OH)2 nanostructure prompt to form the open and porous morphology. The hybrid structure would facilitate charge transport and effectively mitigate the volume changes during long-term charging/discharging cycles. As a consequence, the Cu(OH)2/graphene composite exhibits the highest capacitance of 317 mF/cm2 at the current density of 1 mA/cm2 and superior cyclic stability with no capacitance decay over 20,000 cycles and remarkable rate capability at increased current densities.

The rational design of hierarchical MoS2 nanosheet hollow spheres sandwiched between carbon and TiO2@graphite as an improved anode for lithium-ion batteries.

Molybdenum disulfide (MoS2) shows high capacity but suffers from poor rate capability and rapid capacity decay, which greatly limit its practical applications in lithium-ion batteries. Herein, we successfully prepared MoS2 nanosheet hollow spheres encapsulated into carbon and titanium dioxide@graphite, denoted as TiO2@G@MoS2@C, via hydrothermal and polymerization approaches. In this hierarchical architecture, the MoS2 hollow sphere was sandwiched by graphite and an amorphous carbon shell; thus, TiO2@G@MoS2@C exhibited effectively enhanced electrical conductivity and withstood the volume changes; moreover, the aggregation and diffusion of the MoS2 nanosheets were restricted; this advanced TiO2@G@MoS2@C fully combined the advantages of a three-dimensional architecture, hollow structure, carbon coating, and a mechanically robust TiO2@graphite support, achieving improved specific capacity and long-term cycling stability. In addition, it exhibited the high reversible specific capacity of 823 mA h g-1 at the current density of 0.1 A g-1 after 100 cycles, retaining almost 88% of the initial reversible capacity with the high coulombic efficiency of 99%.

NiO/Ni x Co3-x O4 porous ultrathin nanosheet/nanowire composite structures as high-performance supercapacitor electrodes.

The demand for a new generation of high-safety, long-lifespan, and high-capacity power sources increases rapidly with the growth of energy consumption in the world. Here we report a facile method for preparing architecture materials made of NiO/Ni x Co3-x O4 porous nanosheets coupled with NiO/Ni x Co3-x O4 porous nanowires grown in situ on nickel foams using a hydrothermal method without any binder followed by a heat treatment process. The nanosheet-shaped NiO/Ni x Co3-x O4 species in the nanosheet matrix function well as a scaffold and support for the dispersion of the Ni x Co3-x O4 nanowires, resulting in a relatively loose and open structure within the electrode matrix. Among all composite electrodes prepared, the one annealed in air at 300 °C displays the best electrochemical behavior, achieving a specific capacitance of 270 mF cm-2 at 5 mA cm-2 while maintaining excellent stability (retaining ≈ 89% of the max capacitance after 20 000 cycles), demonstrating its potential for practical application in power storage devices.