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Summary: Although xylose is the secondary dominant sugar derived from biomass, the conversion of xylose to energy products is quite challenging. In this work, a new exoelectrogenic yeast strain (Cystobasidium slooffiae strain JSUX1) that can generate electricity in microbial fuel cell (MFC) by using xylose as the substrate was isolated and identified. After adaptation, it produced significant current output with rapid xylose metabolism. More surprisingly, this strain produced hydrogen gas either in anerobic flask incubation or in MFC, which delivered a 67 mW/m2 power output and 23 L/m3 hydrogen gas in MFC with xylose as fuel. Further electrochemical analysis indicated that riboflavin was secreted by this strain as the electron mediator for efficient electron transfer between cells and electrode in MFC. This is the first microorganism identified that can simultaneously produce bio‐hydrogen and bio‐electricity from xylose, which would diversify the toolbox of biomass energy. [ABSTRACT FROM AUTHOR]

A fluorinated electrolyte consisting of fluorinated ether 1,1,2,2-Tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)propane (F-EPE) and 1,2-Dimethoxyethane (DME) is evaluated as a new electrolyte for Li-S batteries. The coulombic efficiency and capacity retention of Li-S batteries are significantly improved with the use of F-EPE/DME based electrolyte combing with PEO as binder. The Li-S batteries exhibit a high coulombic efficiency of ~96% and capacity retention of 78% after 100 cycles at 0.1C. Moreover, the F-EPE based electrolyte can work well without LiNO3 additive, thus make it possible to eliminate the safety concerns raised by the gassing reaction of LiNO3. The function mechanism of F-EPE as cosolvent was investigated by self-discharge test, polysulfide dissolution experiments, SEM and UV-Vis spectra. The enhanced electrochemical performances can be attributed to that F-EPE cannot only decrease the solubility of lithium polysulfides in electrolyte thus suppress the shuttle effect, but also take part in the formation of passivation film on lithium metal anode, indicating the positive effect of F-EPE on electrochemical properties of Li-S batteries. [ABSTRACT FROM AUTHOR]

Toxicity assessment of water is of great important to the safety of human health and to social security because of more and more toxic compounds that are spilled into the aquatic environment. Therefore, the development of fast and reliable toxicity assessment methods is of great interest and attracts much attention. In this study, by using the electrochemical activity of Shewanella oneidensis MR-1 cells as the toxicity indicator, 3,5-dichlorophenol (DCP) as the model toxic compound, a new biosensor for water toxicity assessment was developed. Strikingly, the presence of DCP in the water significantly inhibited the maximum current output of the S. oneidensis MR-1 in a three-electrode system and also retarded the current evolution by the cells. Under the optimized conditions, the maximum current output of the biosensor was proportional to the concentration of DCP up to 30 mg/L. The half maximal inhibitory concentration of DCP determined by this biosensor is about 14.5 mg/L. Furthermore, simultaneous monitoring of the retarded time (Δ t) for current generation allowed the identification of another biosensor signal in response to DCP which could be employed to verify the electrochemical result by dual confirmation. Thus, the present study has provided a reliable and promising approach for water quality assessment and risk warning of water toxicity. [ABSTRACT FROM AUTHOR]

A series of nickel complexes containing N5-pentadentate ligands with different amine-to-pyridine ratios were studied for electrochemical H2 production in neutral water and the one with a diamine-tripyridine ligand displays a TON of up to 308 000 over 60 h electrolysis at -1.25 V vs. SHE, with a Faradaic efficiency of ~91%. [ABSTRACT FROM AUTHOR]

A patterned LiFePO4 nanorod with a pristine amorphous LiFePO4 surface layer was fabricated by controlling the temperature gradient from the interior to the exterior layer in high-temperature annealing process through designing hierarchical multilayer electrode structure. The three dimensional patterned LiFePO4 nanorods were prepared using tobacco mosaic virus nanoforest arrays. The results indicate that the nano-electrodes nearly reached the theoretical capacity at a very low C rate even without conductive coatings. The amorphous LiFePO4 can fast transport the Li-ion to inside crystal LiFePO4, thus enhancing the rate capability. [ABSTRACT FROM AUTHOR]

Two types of gel polymer electrolytes containing ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMT-TFSI) and N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13-TFSI), are prepared by the solution casting method. Fourier-transform infrared spectroscopy indicates that incorporating both EMI-TFSI and PP13-TFSI can change the phase structure of poly(ethylene oxide) (PEO) and cause a more amorphous phase, can weaken the association between Li+ and TFSI-, and cause more free Li+. The TFSI- anion from these two kinds of ionic liquids plays a main plasticizing role in the P(EO)20LiTFSI systems. From cyclic voltammetry results, the good reversibility of the Li deposition and dissolution, as well as a stable interfacial passive film, can be expected by incorporating PP13-TFSI and a relatively small quantity of EMI-TFSI. The addition of EMI-TFSI and PPI3-TFSI to P(EO)20LiTFSI polymer electrolyte results in an increase, of the ionic conductivity, a wider electrochemical stability window, a decrease of the glass transition temperature (Tg), and a better interfacial stability. The tests performed on Li metal/LiFePO4 batteries containing these two types of polymer electrolytes have shown a good capacity performance at a moderate temperature. [ABSTRACT FROM AUTHOR]

• The combination of natural microbe species enhanced both direct and indirect electron transport mechanisms. • The alliance system expands the utilization spectra of the carbon source. • Riboflavin and Phenazine two electron shuttles work in coordination. Microbial fuel cells with mixed bacteria always show better power output capacity than those with single bacteria due to synergetic effects between species. Here, a rational-designed synthetic three-species alliance system based on Shewanella oneidensis MR-1 (the model exoelectrogen), Pseudomonas aeruginosa, and Lactobacillus plantarum was constructed upon process optimization, the three-species alliance system in MFC delivered a maximum power density of ∼ 207 mW/m2 by using the glucose as the substrate, which was 2 ∼ 58 times higher than that of MFC inoculated with single species. In addition, the synthetic alliance system could generate electricity from broad substrate spectrum (lactose, saccharose, maltose, arabinose, cellobiose) with enhanced performance. Electrochemical and metabolism analysis indicated inter-species synergetic enhancement on charge transfer, substrate utilization, and biofilm formation was the underlying mechanism for performance improvement in MFC by this synthetic alliance system. In this system, L. plantarum uses glucose to produce lactic acid as the electrogenic substrate and electron donor of S. oneidensis MR-1, and P. aeruginosa uses glucose to produce another electron shuttle phenazine, which can also promote the growth of S. oneidensis MR-1 biofilm and help the alliance system to transfer electrons better. This work demonstrated a new strategy to enhance the MFC performance with a rational designed synthetic bacterial community, which would further renew the toolbox for MFC optimization. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) macroporous reduced graphene oxide/polypyrrole (rGO/Ppy) hydrogel assembled by bacterial cells was fabricated and applied for microbial fuel cells. By taking the advantage of electroactive cell-induced bioreduction of graphene oxide and in-situ polymerization of Ppy, a facile self-assembly by Shewanella oneidensis MR-1and in-situ polymerization approach for 3D rGO/Ppy hydrogel preparation was developed. This facile one-step self-assembly process enabled the embedding of living electroactive cells inside the hydrogel electrode, which showed an interconnected 3D macroporous structures with high conductivity and biocompatibility. Electrochemical analysis indicated that the self-assembly of cell-embedding rGO/Ppy hydrogel enhanced the electrochemical activity of the bioelectrode and reduced the electron charge transfer resistance between the cells and the electrode. Impressively, extremely high power output of 3366 ± 42 mW m−2 was achieved from the MFC with cell-embedding rGO/Ppy hydrogel rGO/Ppy, which was 8.6 times of that delivered from the MFC with bare electrode. Further analysis indicated that the increased cell loading by the hydrogel and improved electrochemical activity by the rGO/Ppy composite would be the underlying mechanism for this performance improvement. This study provided a facile approach to fabricate the biocompatible and electrochemical active 3D nanocomposites for MFC, which would also be promising for performance optimization of various bioelectrochemical systems. [Display omitted] • Cell-embedding rGO/Ppy hydrogel was assembled by bacterial cells. • The biohydrogel showed high cell viability and excellent electrochemical activity. • Efficient extracellular electron transfer between cell and electrode was achieved. • Extremely high power output of 3366 ± 42 mW m−2 was achieved from the MFC. [ABSTRACT FROM AUTHOR]

MnO2with different crystallographic forms (α, γ) and morphologies (needles, rods, and spindles) was fabricated via a facile quick-precipitation procedure at a low temperature (about 83 °C) without using any templates or surfactants. The proposed mechanism is focused on the different reaction parameters that affect the behaviors of MnO6octahedron units (basic structural framework of MnO2), which then exert an influence on the formation and stack of nuclei in the crystal growth process. Specific capacitances (Cs) calculated according to the area of the cyclic voltammograms (CV) curves were 233.5, 83.1 F·g−1for the needle- and 95.5, 29.3 F·g−1for the spindle-like products at the scan rate of 5, 100 mV·s−1, respectively. The Csof needle-like samples calculated by discharge curves at the current density of 2 mA·cm2is 209.8 F·g−1, close to the value calculated by CV curves at the scan rate of 5 mV·s−1. This methodology facilitates us to synthesize MnO2with discrepant one-dimensional (1D) nanostructures via a quick, simple, and mild route and may be readily extended to the preparation of many other oxide nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the fabrication of LiMn2O4/graphite batteries and their performance after storage at room temperature. The discharge capacity and cyclic performance of the batteries were investigated. Compared with the batteries without storage, those after storage show better cyclic performance with a capacity retention ratio of 94.2% after 100cycles, yet deliver lower capacity. The ratio of capacity recovery after storage at room temperature for a month is 96.3%. The reason for the capacity fading and better cyclic performance was studied with XRD, SEM, EDS, XPS, cyclic voltammograms and AC impedance. It is found that the lattice parameter of LiMn2O4 shrinks after storage. Mn is dissolved into the electrolyte and deposited on the anode, and the electrode surface is covered by MnO2. The migration resistance of LiMn2O4/electrolyte is increased from 20.28 to 53.31Ω after storage due to the covered MnO2. But the deposited MnO2 also separates the LiMn2O4 from electrolyte, which can improve the cyclic performance. [Copyright &y& Elsevier]