Diffusion-free Grotthuss topochemistry for high-rate and long-life proton batteries

The design of Faradaic battery electrodes that exhibit high rate capability and long cycle life equivalent to those of the electrodes of electrical double-layer capacitors is a big challenge. Here we report a strategy to fill this performance gap using the concept of Grotthuss proton conduction, in which proton transfer takes place by means of concerted cleavage and formation of O-H bonds in a hydrogen-bonding network. We show that in a hydrated Prussian blue analogue (Turnbull's blue) the abundant lattice water molecules with a contiguous hydrogen-bonding network facilitate Grotthuss proton conduction during redox reactions. When using it as a battery electrode, we find high-rate behaviours at 4,000 C (380 Ag-1, 508 mA cm(-2)), and a long cycling life of 0.73 million cycles. These results for diffusion-free Grotthuss topochemistry of protons, in contrast to orthodox battery electrochemistry, which requires ion diffusion inside electrodes, indicate a potential direction to revolutionize electrochemical energy storage for high-power applications

High-Rate and Long-Term Cycle Stability of Li-S Batteries Enabled by Li2S/TiO2-Impregnated Hollow Carbon Nanofiber Cathodes

The high theoretical energy density of lithium-sulfur (Li-S) batteries makes them an alternative battery technology to lithium ion batteries. However, Li-S batteries suffer from low sulfur loading, poor charge transport, and dissolution of lithium polysulfide. In our study, we use the lithiated S, Li2S, as the cathode material, coupled with electrospun TiO2-impregnated hollow carbon nanofibers (TiO2-HCFs), which serve as the conductive agent and protective barrier for Li2S in Li-S batteries. TiO2-HCFs provide much improved electron/ionic conductivity and serve as a physical barrier, which prevents the dissolution of lithium polysulfides. The Li2S/TiO2-HCF composite delivers a discharge capacity of 851 mA h g(Li2S)(-1) at 0.1C and the bilayer TiO2-HCFs/Li2S/TiO2-HCF composite delivers a high specific capacity of 400 mA h g(Li2S)(-1) at 5C.</p

The influence of triethylamine on the hydrodechlorination reactivity of chlorophenols over Raney Ni catalyst

The hydrodechlorination (HDCl) of 2,4-dichlorophenol (2,4-DCP), 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) over Raney Ni in liquid phase with triethylamine (Et3N) under mild conditions was studied. The results showed that Et3N together with solvents significantly affected the HDCl reactivity or selectivity, in which ortho-positioned Cl of chlorophenols (CPs) was easier to be dechlorinated in methanol (MeOH) and ethanol (EtOH), whereas para-positioned Cl was preferentially dechlorinated in water. Different species and action mechanisms of Et3N in water and organic solvents possibly affected the HDCl reactivity or selectivity of CPs over Raney Ni.The hydrodechlorination (HDCl) of 2 4-dichlorophenol (2 4-DCP) 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) over Raney Ni in liquid phase with triethylamine (Et3N) under mild conditions was studied The results showed that Et3N together with solvents significantly affected the HDCl reactivity or selectivity in which ortho-positioned Cl of chlorophenols (CPs) was easier to be dechlorinated in methanol (MeOH) and ethanol (EtOH) whereas para-positioned Cl was preferentially dechlorinated in water Different species and action mechanisms of Et3N in water and organic solvents possibly affected the HDCl reactivity or selectivity of CPs over Raney Ni (C) 2010 Elsevier BV All rights reserve

High-Rate Performance and Ultralong Cycle Life Enabled by Hybrid Organic-Inorganic Vanadyl Ethylene Glycolate for Lithium-Ion Batteries

Transition metal oxides (TMOs) possess high theoretical capacity and serve as promising anode candidates for lithium-ion batteries. However, the intrinsic low conductivity handicaps the application of TMOs. Molecular modification by coupling TMOs structure with Li-ion conductive polymer ligands can facilitate the kinetics of electrochemical lithiation/delithiation process. Herein, a proof-of-concept investigation on the Li-ion storage capability by vanadyl ethylene glycolate (VEG) is achieved with the improvement of Li-ion diffusion kinetics by modifiying the vanadium oxide with organic ligands. VEG demonstrates unprecedented advantage for fast rate capability, stable cycleability, and high capacity at both room temperarture (25 degrees C) and elevated temperature (60 degrees C)

Improved Antitumor Efficacy and Pharmacokinetics of Bufalin via PEGylated Liposomes

Abstract Bufalin was reported to show strong pharmacological effects including cardiotonic, antiviral, immune-regulation, and especially antitumor effects. The objective of this study was to determine the characterization, antitumor efficacy, and pharmacokinetics of bufalin-loaded PEGylated liposomes compared with bufalin entity, which were prepared by FDA-approved pharmaceutical excipients. Bufalin-loaded PEGylated liposomes and bufalin-loaded liposomes were prepared reproducibly with homogeneous particle size by the combination of thin film evaporation method and high-pressure homogenization method. Their mean particle sizes were 127.6 and 155.0 nm, mean zeta potentials were 2.24 and − 18.5 mV, and entrapment efficiencies were 76.31 and 78.40%, respectively. In vitro release profile revealed that the release of bufalin in bufalin-loaded PEGylated liposomes was slower than that in bufalin-loaded liposomes. The cytotoxicity of blank liposomes has been found within acceptable range, whereas bufalin-loaded PEGylated liposomes showed enhanced cytotoxicity to U251 cells compared with bufalin entity. In vivo pharmacokinetics indicated that bufalin-loaded PEGylated liposomes could extend or eliminate the half-life time of bufalin in plasma in rats. The results suggested that bufalin-loaded PEGylated liposomes improved the solubility and increased the drug concentration in plasma

Kinetics Tuning the Electrochemistry of Lithium Dendrites Formation in Lithium Batteries through Electrolytes

Lithium batteries are one of the most advance energy storage devices in the world and have attracted extensive research interests. However, lithium dendrite growth was a safety issue which handicapped the application of pure lithium metal in the negative electrode. In this investigation, two solvents, propylene carbonate (PC) and 2-methyl-tetrahydrofuran (2MeTHF), and four Li+ salts, LiPF6, LiAsF6, LiBF4 and LiClO4 were investigated in terms of their effects on the kinetics of lithium dendrite formation in eight electrolyte solutions. The kinetic parameters of charge transfer step (exchange current density, j(0), transfer coefficient, a) of Li+/Li redox system, the mass transfer parameters of Li+ (transfer number of Li+, t(Li+), diffusion coefficient of Li+, DLI+), and the conductivity (kappa) of each electrolyte were studied separately. The results demonstrate that the solvents play a critical role in the measured j(0), t(Li+), DLi+, and kappa of the electrolyte, while the choice of Li+ salts only slightly affect the measured parameters. The understanding of the kinetics will gain insight into the mechanism of lithium dendrite formation and provide guidelines to the future application of lithium metal.</p

High-Rate, Durable Sodium-Ion Battery Cathode Enabled by Carbon-Coated Micro-Sized Na \u3c inf\u3e 3 V \u3c inf\u3e 2 (PO \u3c inf\u3e 4 ) \u3c inf\u3e 3 Particles with Interconnected Vertical Nanowalls

Na-ion batteries have been regarded as promising alternatives for Li-ion batteries due to the extensive sodium reserves in the world. Na3V2(PO4)3 has been proved to be a good candidate of the cathode materials in Na-ion batteries but the intrinsic low electrical conductivity and sluggish kinetics handicapped its application. Here, 3D hierarchical Na3V2(PO4)3 particles are synthesized by a facile hydrothermal method, constructed by carbon-coated 2D Na3V2(PO4)3 nanowalls. Superior cell performance of high rate capability and cycle stability are observed in the well-defined structure. As the cathode in Na-ion batteries, it delivers a high capacity almost reaching the theoretical one and exhibits high capacity retention. The enhanced rate capability and cycle performance can be attributed to the improved electrical conductivity from the interconnected carbon layer and the shortened ion diffusion length and high specific surface area from the nanowalls