The Experts below are selected from a list of 28332 Experts worldwide ranked by ideXlab platform

Chunsheng Wang - One of the best experts on this subject based on the ideXlab platform.

  • an advanced mos2 Carbon Anode for high performance sodium ion batteries
    Small, 2015
    Co-Authors: Jingjing Wang, Chao Luo, Tao Gao, Alex Langrock, Alice Mignerey, Chunsheng Wang
    Abstract:

    Molybdenum disulfide (MoS2 ) is a promising Anode for high performance sodium-ion batteries due to high specific capacity, abundance, and low cost. However, poor cycling stability, low rate capability and unclear electrochemical reaction mechanism are the main challenges for MoS2 Anode in Na-ion batteries. In this study, molybdenum disulfide/Carbon (MoS2 /C) nanospheres are fabricated and used for Na-ion battery Anodes. MoS2 /C nanospheres deliver a reversible capacity of 520 mAh g(-1) at 0.1 C and maintain at 400 mAh g(-1) for 300 cycles at a high current density of 1 C, demonstrating the best cycling performance of MoS2 for Na-ion batteries to date. The high capacity is attributed to the short ion and electron diffusion pathway, which enables fast charge transfer and low concentration polarization. The stable cycling performance and high coulombic efficiency (∼100%) of MoS2 /C nanospheres are ascribed to (1) highly reversible conversion reaction of MoS2 during sodiation/desodiation as evidenced by ex-situ X-ray diffraction (XRD) and (2) the formation of a stable solid electrolyte interface (SEI) layer in fluoroethylene Carbonate (FEC) based electrolyte as demonstrated by fourier transform infrared spectroscopy (FTIR) measurements.

  • a porous silicon Carbon Anode with high overall capacity on Carbon fiber current collector
    Electrochemistry Communications, 2010
    Co-Authors: Juche Guo, Chunsheng Wang
    Abstract:

    article i nfo A porous silicon-Carbon Anode on a lightweight Carbon fiber current collector is reported here for lithium- ion batteries. This Si-C Anode was synthesized through a one-step Carbonization of a Si-poly(acrylonitrile-co- methyl acrylate) precursor, which was directly deposited on a Carbon fiber mat. The Carbon fiber curent collector allows higher loading of active materials, resulting in high energy to mass and area ratios. The obtained Si-C electrode demonstrated superior overall capacity, cyclability, and rate capacity.

Benjamin Kruner - One of the best experts on this subject based on the ideXlab platform.

  • enhanced performance stability of Carbon titania hybrid electrodes during capacitive deionization of oxygen saturated saline water
    Electrochimica Acta, 2017
    Co-Authors: Pattarachai Srimuk, Marco Zeiger, Nicolas Jackel, Aura Tolosa, Benjamin Kruner
    Abstract:

    Abstract Capacitive deionization (CDI) is a promising technology for the desalination of brackish water due to its potentially high energy efficiency and its relatively low costs. One of the most challenging issues limiting current CDI cell performance is poor cycling stability. CDI can show highly reproducible salt adsorption capacities (SACs) for hundreds of cycles in oxygen-free electrolyte, but by contrast poor stability when oxygen is present due to a gradual oxidation of the Carbon Anode. This oxidation leads to increased concentration of oxygen-containing surface functional groups within the micropores of the Carbon Anode, increasing parasitic co-ion current and decreasing SAC. In this work, activated Carbon (AC) was chemically modified with titania to achieve additional catalytic activity for oxygen-reduction reactions on the electrodes, preventing oxygen from participating in Carbon oxidation. Using this approach, we show that the SAC can be increased and the cycling stability prolonged in electrochemically highly demanding oxygen-saturated saline media (5 mM NaCl). The electrochemical oxygen reduction reaction (ORR) occurring in our CDI cell was evaluated by the number of electron transfers during charging and discharging. It was found that, depending on the amount of titania, different ORR pathways take place. A loading of 15 mass% titania presents the best CDI performance and also demonstrates a favorable three-electron transfer ORR.

Mark I Pownceby - One of the best experts on this subject based on the ideXlab platform.

  • development of a niobium doped titania inert Anode for titanium electrowinning in molten chloride salts
    Faraday Discussions, 2016
    Co-Authors: Graeme A Snook, Katherine Mcgregor, Andrew J Urban, Marshall R Lanyon, Richard Donelson, Mark I Pownceby
    Abstract:

    The direct electrochemical reduction of solid titanium dioxide in a chloride melt is an attractive method for the production of titanium metal. It has been estimated that this type of electrolytic approach may reduce the costs of producing titanium sponge by more than half, with the additional benefit of a smaller environmental footprint. The process utilises a consumable Carbon Anode which releases a mixture of CO2 and CO gas during electrolysis, but suffers from low current efficiency due to the occurrence of parasitic side reactions involving Carbon. The replacement of the Carbon Anode with a cheap, robust inert Anode offers numerous benefits that include: elimination of Carbon dioxide emissions, more efficient cell operation, opportunity for three-dimensional electrode configurations and reduced electrode costs. This paper reports a study of Nb-doped titania Anode materials for inert Anodes in a titanium electrolytic reduction cell. The study examines the effect of niobium content and sintering conditions on the performance of Nb-doped TiO2 Anodes in laboratory-scale electrolysis tests. Experimental findings, including performance in a 100 h laboratory electrolysis test, are described.

Pattarachai Srimuk - One of the best experts on this subject based on the ideXlab platform.

  • enhanced performance stability of Carbon titania hybrid electrodes during capacitive deionization of oxygen saturated saline water
    Electrochimica Acta, 2017
    Co-Authors: Pattarachai Srimuk, Marco Zeiger, Nicolas Jackel, Aura Tolosa, Benjamin Kruner
    Abstract:

    Abstract Capacitive deionization (CDI) is a promising technology for the desalination of brackish water due to its potentially high energy efficiency and its relatively low costs. One of the most challenging issues limiting current CDI cell performance is poor cycling stability. CDI can show highly reproducible salt adsorption capacities (SACs) for hundreds of cycles in oxygen-free electrolyte, but by contrast poor stability when oxygen is present due to a gradual oxidation of the Carbon Anode. This oxidation leads to increased concentration of oxygen-containing surface functional groups within the micropores of the Carbon Anode, increasing parasitic co-ion current and decreasing SAC. In this work, activated Carbon (AC) was chemically modified with titania to achieve additional catalytic activity for oxygen-reduction reactions on the electrodes, preventing oxygen from participating in Carbon oxidation. Using this approach, we show that the SAC can be increased and the cycling stability prolonged in electrochemically highly demanding oxygen-saturated saline media (5 mM NaCl). The electrochemical oxygen reduction reaction (ORR) occurring in our CDI cell was evaluated by the number of electron transfers during charging and discharging. It was found that, depending on the amount of titania, different ORR pathways take place. A loading of 15 mass% titania presents the best CDI performance and also demonstrates a favorable three-electron transfer ORR.

Ju Li - One of the best experts on this subject based on the ideXlab platform.

  • a high performance sodium ion battery enhanced by macadamia shell derived hard Carbon Anode
    Nano Energy, 2017
    Co-Authors: Yaxiang Lu, Yuesheng Wang, Yongsheng Hu, Yuheng Zheng, Ju Li
    Abstract:

    Abstract Hard Carbon Anode materials for sodium-ion batteries (SIB) have usually been tested in half-cells by cycling between 0–2 V, and is believed to exhibit low rate capability. However, we find that the specific capacity, the rate performance, and the cycling performance may all be severely underestimated with the traditional half-cell cycling evaluation method, due to premature truncation of part II of the capacity (part I is “sloping”, part II is “plateauing”, while part III is Na metal deposition). Here we introduce a sodium-matched SIB full-cell architecture, with newly developed hard Carbon derived from macadamia shell (MHC) as Anode and Na [ Cu 1 / 9 Ni 2 / 9 Fe 1 / 3 Mn 1 / 3 ] O 2 (NCNFM) as the cathode material, with Anode/cathode areal capacity ratio of 1.02–1.04. Our carefully balanced full-cells exhibit a cell-level theoretical specific energy of 215 Wh kg −1 at C/10 and 186 Wh kg −1 at 1C based on cathode-active and Anode-active material weights, and an outstanding capacity retention of 70% after 1300 cycles ( ∼ 2000 h ). Traditional half-cell test (THT) of MHC using superabundant Na metal counter electrode shows only 51.7 mAh g −1 capacity at 1C, and appears to die in no more than 100 h due to low open-circuit voltage slope and large polarization. A revised half-cell test (RHT) which shows much better agreements with full-cell test results, delivers a specific capacity of 314 mAh g −1 , with an initial Coulombic efficiency of ∼ 91.4 % , which is comparable to that of graphite Anode in lithium-ion batteries.