Modeling and synthesis of carbon-coated LiMnPO4 cathode material: Experimental investigation and optimization using response surface methodology

Nanostructured LiMnPO4 cathode materials for lithium-ion batteries (LIBs) have been successfully prepared by a modified solvothermal method under controlled conditions. Polyethylene glycol (PEG-10000) was used as a solvent to optimize the particle size/mor­phology and as a carbon conductive matrix. In order to investigate the effect of synthesis parameters such as concentration of PEG-10000, reaction time and reaction temperature on the LiMnPO4 phase purity, Response surface methodology was carried out to find variations in purity results across the composition. The purity of all materials was checked using HighScore software by comparing the matched lines score to ones of reference data. As a result, it has been found that the pure phospho-olivine material LiMnPO4 can be syn­thesized using the following optimum conditions: PEG concentration = 0.1 mol l-1, reaction time = 180 min, and reaction temperature = 250 °C. The as-prepared LiMnPO4 under opti­mum conditions delivered an initial discharge capacity of 128.8 mAh g-1 at 0.05 C‑rate. The present work provides insights and suggestions for optimizing synthesis conditions of this material, which has been considered the next promising cathode candidate for high-energy lithium-ion batteries

Low-Cost Electrode Modification to Upgrade the Bioelectrocatalytic Oxidation of Tannery Wastewater Using Acclimated Activated Sludge

Effective and eco-friendly technologies are required for the treatment of tannery wastewater as its biological toxicity and large volume leads toground water pollution. Hydrophobic (unmodified carbon felt) and hydrophilic modified carbon felt with Linde Type A zeolite (LTA zeolite) and bentonite were examined for their effects on bacterial attachment, current generation, and tannery wastewater treatment efficiency. Chronoamperometry and cyclic voltammetry confirmed the higher electron transfer obtained with modified anodes. Maximum current densities of 24.5 and 27.9 A/m² were provided with LTA zeolite and bentonite-modified anodes, respectively, while the unmodified carbon felt gave a maximum current density of 16.9 A/m². Compared with hydrophobic unmodified carbon felt, hydrophilic modified electrodes increased the exploitation of the internal surface area of the 3D structure of the carbon felt by the electroactive biofilm. The study revealed 93.8 ± 1.7% and 96.3 ± 2.1% of chemical oxygen demand (COD) reduction for LTA zeolite and bentonite, respectively. Simultaneous chromium removal was achieved with values of 94.6 ± 3.6 and 97.5 ± 2.2 for LTA zeolite and bentonite, respectively. This study shows the potential approach of carbon felt clay modification for the efficient tannery wastewater treatment using bioelectrochemicals systems (BESs) accompanied with high current recovery

Mechanosynthezized Zn3V2O8 Mixed Oxide as Efficient Catalyst of Xylose Conversion to Glycolic Acid in Water

International audienceDifferent catalytic materials of mixed oxide of zinc and vanadium Zn3V2O8 were synthesized using co-precipitation, combustion, alginate gelation and mechanosynthesis methods. The synthesized mixed oxide Zn3V2O8 were characterized by several techniques including XRD, SEM, EDX, XPS and BET. Structural measurement revealed the influence of the synthesis method on the physical and catalytic proprieties of Zn3V2O8 materials. Catalytic performance of Zn3V2O8 has been studied by oxidation of xylose to organic acids in water at 150 degrees C for 1 h. Significantly, this is the first time that the Zn3V2O8 nano-oxide was used as catalyst for xylose oxidation in water. Zn3V2O8 can efficiently catalyze the synthesis of glycolic acid (70% selectivity and 60% yield) from xylose with excellent stability and reusability. The ability to regenerate the Zn3V2O8 was also assessed by determining the change in the reaction indices in successive reaction-regeneration cycles