A graphene-like hollow sphere anode for lithium-ion batteries.

We report a flash Joule heating method for the rapid preparation of graphene-like materials. The L-GHS exhibited a uniform diameter of 200 nm and an ideal specific surface area of 670 m2 g-1. Meanwhile, the specific capacity of L-GHS remained at 942 mA h g-1 after 600 cycles (1 A g-1), which shows excellent electrochemical performance.

A Potential Polycarbonyl Polyimide as Anode Material for Lithium-Ion Batteries.

Organic polymers have been considered reliable candidates for lithium storage due to their high capacity and lack of volume expansion. Compared with other organic polymers, polyimide has become a very promising electrode material for lithium-ion batteries (LIBs) because of its easy synthesis, customizable structure and structural stability. A large number of studies have confirmed that the benzene ring structure of polyimide has strong lithium storage capacity as an anode material. Hence, we designed and synthesized polyimide organic polymer (PBPAQ) for the first time. The unique spherical flower structure of this material enhances the interaction between the electrode material and the electrolyte by increasing the contact area. The PBPAQ anode has a specific discharge capacity of 738 mAh g-1 after 100 cycles at 0.1 A g-1 . The excellent lithium storage performance of this material laid a foundation for the research of the anode of LIBs in the future.

Boosting Magnesium Ion Storage Behavior via Heteroelement Doping in a Porous Tunnel Framework Cathode for Aqueous Mg-Ion Batteries.

To relieve the overwhelming pressure on fossil energy, aqueous magnesium ion batteries attracted tremendous attention owing to their low cost and high safety. However, the cathode materials are apt to occur lattice distortion because of the electrostatic interaction between magnesium ions and crystal. The 2×2 manganese octahedral molecular sieve with potassium ions and water located in the tunnels (K-OMS-2), utilized as a cathode material for chargeable magnesium ions batteries, is exposed to irreversible Mg2+ intercalation/deintercalation due to lattice distortion, which heavily damages the electrochemical properties and declines the capacity. Herein, we carry out an ion doping strategy to overcome the above issues, leading to an enhanced Mg Mg2+ storage behavior. The Nb or V cation is successfully doped into K-OMS-2 by a facile reflux method under room temperature. The specific surface area is enlarged by the addition of cations, which promise a large electrode-electrolyte contact area. The Nb and V doped K-OMS-2 present a capacity of 252.6 and 265.9 mAh/g at 20 mA/g, respectively. This work demonstrates an ion doping approach toward exploiting the stable and high-capacity Mg-ion battery cathode and provides potential cathode materials for a large-scale aqueous Mg-ion-based energy storage system.

A Novel Graphene Based Bi-Function Humidity Tolerant Binder for Lithium-Ion Battery.

Binders play a critical role in rechargeable lithium-ion batteries (LIBs) by holding granular electrode materials, conductive carbons, and current collectors firmly together to form and maintain a continuous electron conduction phase with sufficient mechanical strength. In the commercial LIBs, the dominant binder is polyvinylidene fluoride for the cathode (LiCoO2 , LiFePO4 , LiNix Coty Mnz O2 , etc.) and carboxyl methylcellulose/styrene-butadiene rubber for the anode (graphite and Li4 Ti5 O12 ). However, these polymer binders have several drawbacks, particularly, a lack of electronic and lithium-ion conductivities. Here, a novel organic/inorganic hybrid conductive binder (LAP-rGO) for both the anode and cathode of LIBs is reported. The binder consists of 2D reduced graphene oxide sheets with anchored long alkane chains. Electrodes prepared using this binder exhibit sufficient high bond strength, fast electrolyte diffusion, high rate charge/discharge performance, and excellent cycling stability. Around 130 mAh g-1 capacity enhancement at 5C is demonstrated for LiFePO4 and Li4 Ti5 O12 electrodes owing to the combined improvement in electron and lithium ion transportation. LAP-rGO bond graphite anode shows specific capacity beyond its theoretical value. Electrode slurries prepared using this new binder have superior processing and coating properties that can be prepared under a high humidity and dried using less energy.

A Nucleophilic Chemical Probe Targeting Electrophilic Functional Groups in an Untargeted Way to Explore Cysteine Modulators in Natural Products.

The vital roles of biologically relevant cysteines have been discovered from proteins that are promising targets for new drugs or chemical tools. Therefore, new electrophilic small molecules that can covalently modulate these cysteines have attracted immense interest. Because of their extremely wide chemical diversity, electrophilic natural products (NPs) have been studied as promising sources of cysteine modulators. Previous studies have developed chemical probes to facilitate the detection and isolation of electrophilic NPs. To address the problems with the current methods, including their low sensitivity, high false-positive rate, and dependence on performing manual processing with a plethora of spectra, we report a chemical probe that can first covalently capture electrophilic NPs from natural resources and then produce sensitive reporter ion signals that are specific for the detected NPs. We applied this untargeted method to explore electrophilic NPs from natural resources and found that the complexity of electrophilic NPs was beyond our expectations. We used this chemical probe to identify a new electrophilic furanosesterterpene (BG-1) from an extract of Ginkgo biloba that targets the Cys207 of acyl-CoA thioesterase 7 (ACOT7).

Simultaneously boosting hydrogen production and ethanol upgrading using a highly-efficient hollow needle-like copper cobalt sulfide as a bifunctional electrocatalyst.

Electrocatalytic water splitting used for generating clean and sustainable hydrogen (H2) can be very promising to address current energy shortage and associated environmental issues. However, this methodology is severely impeded by the tardy oxygen evolution reaction (OER). Hence, designing a preferable kinetics and thermodynamics oxidation reaction that supersede OER is very significant for the energy-saving production of H2. Herein, hollow needle-like copper cobalt sulfide was constructed on carbon cloth (CuCo2S4/CC) as a bifunctional electrocatalyst to accelerate H2 generation and simultaneously convert ethanol into value-added acetic acid. Thanks to the synergistic effect and unique structure of Cu and Co, CuCo2S4/CC displays superior catalytic activity and durability in ethanol oxidation reaction (EOR) with a low potential of 1.38 V vs. RHE (@10 mA cm-2). Meanwhile, it exhibits excellent hydrogen evolution reaction (HER) performance. The homemade CuCo2S4/CC//CuCo2S4/CC ethanol-water electrolyser only demands a voltage of 1.59 V to deliver 10 mA cm-2, 150 mV less than that used for ordinary water splitting. This shows that the ethanol-water electrolyser elaborated here holds encouraging potential in the energy-saving production of H2 and oxidation of ethanol into value-added acetic acid. This present work may open the way for the rational design of other electrocatalysts for efficient biomass oxidation reaction and relevant H2 production applications.

Copper niobate nanowires immobilized on reduced graphene oxide nanosheets as rate capability anode for lithium ion capacitor.

Binary metal niobium oxides can offer a higher specific capacity compared to niobium pentoxide (Nb2O5) and thus are ideal anode candidates for lithium ion capacitors (LICs). However, their lower electronic conductivity limits their ability to achieve high energy and power densities. In this paper, one-dimensional (1D) copper niobate (CuNb2O6) nanowires are successfully prepared by electrospinning technology and then immobilized on two-dimensional (2D) reduced graphene oxide (rGO) nanosheets to form a unique 1D nanowire/2D nanosheet CuNb2O6/rGO structure. The 1D/2D CuNb2O6/rGO electrode exhibits a high specific capacity of 312.2 mAh g-1 at 100 mA g-1 as the anode of LICs. The proposed Li+ storage mechanism of the CuNb2O6 anode involves CuNb2O6 decomposition into lithium niobate (Li3NbO4) and copper (Cu) during the initial lithium insertion process. The intercalation-type Li3NbO4 will further serve as the host to Li+ and the inactive Cu phase will act as a conductive network for electron transportation. Furthermore, the energy density of the assembled CuNb2O6/rGO//activated carbon (CuNb2O6/rGO//AC) device could achieve a value as high as 92.1 Wh kg-1 and could thus be considered as a possible alternative electrode material for high energy and power LICs.

Development of coumarine derivatives as potent anti-filovirus entry inhibitors targeting viral glycoprotein.

Filoviruses, including Ebolavirus (EBOV), Marburgvirus (MARV) and Cuevavirus, cause hemorrhagic fevers in humans with up to 90% mortality rates. In the 2014-2016 West Africa Ebola epidemic, there are 15,261 laboratory confirmed cases and 11,325 total deaths. The lack of effective vaccines and medicines for the prevention and treatment of filovirus infection in humans stresses the urgency to develop antiviral therapeutics against filovirus-associated diseases. Our previous study identified a histamine receptor antagonist compound CP19 as an entry inhibitor against both EBOV and MARV. The preliminary structure-activity relationship (SAR) studies of CP19 showed that its piperidine, coumarin and linker were related with its antiviral activities. In this study, we performed detailed SAR studies on these groups with synthesized CP19 derivatives. We discovered that 1) the piperidine group could be optimized with heterocycles, 2) the substitution groups of C3 and C4 of coumarin should be relatively large hydrophobic groups and 3) the linker part should be least substituted. Based on the SAR analysis, we synthesized compound 32 as a potent entry inhibitor of EBOV and MARV (IC50 = 0.5 µM for EBOV and 1.5 µM for MARV). The mutation studies of Ebola glycoprotein and molecular docking studies showed that the coumarin and its substituted groups of compound 32 bind to the pocket of Ebola glycoprotein in a similar way to the published entry inhibitor compound 118a. However, the carboxamide group of compound 32 does not have strong interaction with N61 as compound 118a does. The coumarin skeleton structure and the binding model of compound 32 elucidated by this study could be utilized to guide further design and optimization of entry inhibitors targeting the filovirus glycoproteins.

Silicon Nanoparticles Embedded in N-Doped Few-Layered Graphene: Facile Synthesis and Application as an Effective Anode for Lithium Ion Batteries.

A fast one-step arc discharge exfoliation method is employed to synthesize Si/graphene composites by using a graphite rod filled with a mixture of Si powder and urea as a cathode. During the arc discharge process, the use of urea allows both the introduction of nitrogen atoms into the graphene and the uniform sealing of Si nanoparticles between the thin graphene sheets to occur simultaneously. The resulting N-doped graphene nanosheets embedded with Si (Si@NG) can act as an electrode material for lithium-ion batteries and delivers the reversible capacity of 1030 mAh g-1 with a current density of 200 mA g-1 over 100 cycles along with an outstanding coulombic efficiency of 96.84 %. The remarkable electrochemical rate capability performance can be owed to the multiple role of NG, which not only serves as a three-dimensional conductive support, but also effectively limits the volume variation of Si nanoparticles. The approach proposed here is expected to be extended to the preparation of other alloy anode/graphene hybrids for lithium ion batteries.

Electrolytic extraction of dysprosium and thermodynamic evaluation of Cu-Dy intermetallic compound in eutectic LiCl-KCl.

The electrochemical reduction of dysprosium(iii) was studied on W and Cu electrodes in eutectic LiCl-KCl by transient electrochemical methods. Cyclic voltammogram and current reversal chronopotentiogram results demonstrated that dysprosium(iii) was directly reduced to dysprosium (0) on the W electrode through a single-step process with the transfer of three electrons. Electrochemical measurements on the Cu electrode showed that different Cu-Dy intermetallics are formed. Moreover, the thermodynamic properties of Cu-Dy intermetallic compounds were estimated by open circuit chronopotentiometry in a temperature range of 773-863 K. Using the linear polarization method, the exchange current density (j 0) of dysprosium in eutectic LiCl-KCl on the Cu electrode was estimated, and the temperature dependence of j 0 was studied to estimate the activation energies associated with Dy(iii)/Cu5Dy and Dy(iii)/Cu9/2Dy couples. In addition, potentiostatic electrolysis was conducted to extract dysprosium on the Cu electrode, and five Cu-Dy intermetallic compounds, CuDy, Cu2Dy, Cu9/2Dy, Cu5Dy and Cu0.99Dy0.01 were identified by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry. Meanwhile, the change of dysprosium(iii) concentration was monitored using inductively coupled plasma-atomic emission spectrometry, and the maximum extraction efficiency of dysprosium was found to reach 99.2%.