A Stable High-Capacity Lithium-Ion Battery Using a Biomass-Derived Sulfur-Carbon Cathode and Lithiated Silicon Anode.

A full lithium-ion-sulfur cell with a remarkable cycle life was achieved by combining an environmentally sustainable biomass-derived sulfur-carbon cathode and a pre-lithiated silicon oxide anode. X-ray diffraction, Raman spectroscopy, energy dispersive spectroscopy, and thermogravimetry of the cathode evidenced the disordered nature of the carbon matrix in which sulfur was uniformly distributed with a weight content as high as 75 %, while scanning and transmission electron microscopy revealed the micrometric morphology of the composite. The sulfur-carbon electrode in the lithium half-cell exhibited a maximum capacity higher than 1200 mAh g , reversible electrochemical process, limited electrode/electrolyte interphase resistance, and a rate capability up to C/2.

Organic Polyradicals as Redox Mediators: Effect of Intramolecular Radical Interactions on Their Efficiency.

The spin-spin interactions between unpaired electrons in organic (poly)radicals, especially nitroxides, are largely investigated and are of crucial importance for their applications in areas such as organic magnetism, molecular charge transfer, or multiple spin labeling in structural biology. Recently, 2,2,6,6-tetramethylpiperidinyloxyl and polymers functionalized with nitroxides have been described as successful redox mediators in several electrochemical applications; however, the study of spin-spin interaction effect in such an area is absent. This communication reports the preparation of a novel family of discrete polynitroxide molecules, with the same number of radical units but different arrangements to study the effect of intramolecular spin-spin interactions on their electrochemical potential and their use as oxidation redox mediators in a Li-oxygen battery.

Alternative lithium-ion battery using biomass-derived carbons as environmentally sustainable anode.

Disordered carbons derived from biomass are herein efficiently used as an alternative anode in lithium-ion battery. Carbon precursor obtained from cherry pit is activated by using either KOH or HPO, to increase the specific surface area and enable porosity. Structure, morphology and chemical characteristics of the activated carbons are investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetry (TG), Raman spectroscopy, nitrogen and mercury porosimetry.

Combined Influence of Meso- and Macroporosity of Soft-Hard Templated Carbon Electrodes on the Performance of Li-O Cells with Different Configurations.

Li-O batteries can offer large discharge capacities, but this depends on the morphology of the discharged LiO, which in turn is strongly affected by the nanostructured carbon used as support in the air cathode. However, the relation with the textural parameters is complex. To investigate the combined effect of channels of different sizes, meso-macroporous carbons with similar mesopore volume but different pore size distribution were prepared from the polymerization of resorcinol-formaldehyde (RF) in the presence of surfactants and micro-CaCO particles.

Mass-transport Control on the Discharge Mechanism in Li-O2 Batteries Using Carbon Cathodes with Varied Porosity.

By comparing carbon electrodes with varying porosity in Li-O2 cells, we show that the effect of electrolyte stirring at a given current density can result in a change from 2D to 3D growth of discharged deposits. The change of morphology is evident using electron microscopy and by analyzing electrode pore size distribution with respect to discharge capacity. As a consequence, carbon electrodes with different textural properties exhibit different capacity enhancements in stirred-electrolyte cells.

Spatial Distributions of Discharged Products of Lithium-Oxygen Batteries Revealed by Synchrotron X-ray Transmission Microscopy.

The discharge products of ether-based Li-O2 cells were grown directly on common carbon-coated TEM grids and observed by oxidation-state-sensitive full field transmission soft X-ray microscopy (TXM). The acquired data have permitted to quantify and localize with spatial resolution the distribution of the oxygen discharge products in these samples (i.e.

Influence of the operation conditions on CO2 capture by CaO-derived sorbents prepared from synthetic CaCO3.

In this work, a statistical experimental design is performed in order to prepare CaCO3 materials for use as CaO-based CO2 sorbent precursors. The influence of different operational parameters such as synthesis temperature (ST), stirring rate (SR) and surfactant percent (SP) on CO2 capture is studied by applying Response Surface Methodology (RSM). The samples were characterized using different analytical techniques including X-ray diffraction, N2 adsorption isotherm analysis and Scanning Electron Microscopy-X-ray Energy Dispersive Spectroscopy (SEM-EDX).

Modification of carbon screen-printed electrodes by adsorption of chemically synthesized Bi nanoparticles for the voltammetric stripping detection of Zn(II), Cd(II) and Pb(II).

A simple procedure for the chemical synthesis of bismuth nanoparticles and subsequent adsorption on commercial screen-printed carbon electrodes offer reliable quantitation of trace zinc, cadmium and lead by anodic stripping square-wave voltammetry in nondeareated water samples. The influence of two hydrodynamic configurations (convective cell and flow cell) and the effect of various experimental variables upon the stripping signals at the bismuth-coated sensor are explored. The square-wave peak current signal is linear over the low ng mL(-1) range (120 s deposition), with detections limits ranging from 0.