Electrochemical and structural characteristics of niobium(V) oxide in a rechargeable lithium battery

The discharge behaviour of T-Nb₂O₅ in various electrolytes is unaffected by the choice of solvent, but is strongly dependent on the crystal radius of the solute cation species. Thermodynamic and structural studies show that this is due to the insertion of unsolvated Li⁺ ions into the crystal lattice. The graphite content of the Nb₂O₅ electrode has a marked influence on the cycling behaviour on account of the decrease in the oxide conductivity with discharge. Furthermore, the chemical diffusion coefficient of Li⁺ ions in Nb₂O₅ is about 10⁻¹⁰ cm² s⁻¹, which is one order of magnitude smaller than that in V₂O₅ with a layered structure.     

Development of membranes and a study of their interfaces for rechargeable lithium–air battery

This paper describes an investigation with an objective to screen and select high performance membrane materials for a working, rechargeable lithium–air battery. Membrane laminates comprising glass–ceramic (GC) and polymer–ceramic (PC) membranes were assembled, evaluated and analyzed. A superionic conducting GC membrane with a chemical composition of Li_1+xAl_xGe_2−x(PO₄)₃ (x = 0.5) was used. Polymer membranes comprising of PC(BN), PC(AlN), PC(Si₃N₄) and PC(Li₂O) electrochemically coupled the GC membrane with the lithium anode. The cell and membrane laminates were characterized by determining cell conductivity, open circuit voltage and carrier concentration and its mobility. The measurements identified Li₂O and BN as suitable dopants in polymer matrix which catalyzed anodic charge transfer reaction, formed stable SEI layer and provided high lithium ion conductivity.     

Synthesis and evaluation of polythiocyanogen (SCN)x as a rechargeable lithium-ion battery electrode material

Polythiocyanogen, (SCN)_x, is a promising lithium-ion battery electrode material due to its high theoretical capacity (462 mAh g⁻¹), safe operation, inexpensive raw materials, and a simple and less energy-intensive manufacturing process. The (SCN)_x was prepared from the solution of trithiocyanate (SCN)₃⁻ in methylene dichloride (MDC), which was prepared by electrochemical oxidation of ammonium thiocyanate (NH₄SCN) in a two-phase electrolysis medium of 1.0 M NH₄SCN in 0.50 M H₂SO₄ + MDC. The (SCN)₃⁻ underwent auto catalytic polymerization to (SCN)_x during MDC removal. Battery electrodes with (SCN)_x as the active material were prepared, and tested in Swagelok cells using lithium foil as the counter and reference electrode. The cells delivered capacities in the range of 200-275 mAh g⁻¹ at the discharge-charge rate of 0.2 C. The cells were tested up to 20 cycles and showed repeatable performance with a coulombic efficiency of 97% at the 20th cycle. The results presented here indicate that (SCN)_x is a promising lithium-ion battery electrode-material candidate for further studies.     

Synthesis and characterization of the iron/copper composite as an electrode material for the rechargeable alkaline battery

Iron/copper composite particles were synthesized by a chemical reduction method and then used as the anode material for a rechargeable alkaline battery. The particle size and structure of the samples were characterized by SEM and XRD. Their electrochemical performance was also studied. The results showed that the iron/copper composite prepared by this method is nanosized. Copper improves the electron transfer between particles, and the nanosized iron/copper composite not only has a high electrochemical capacity of up to 800 mAh g⁻¹(Fe to Fe(III)), but also has an excellent rate-capacity performance at a current density of 3200 mA g⁻¹. Compared with the iron nanoparticle without copper, the iron/copper composite sample maintains a smaller particle size during electrochemical cycling, and therefore improves the cycling stability of the iron electrode.     

Allometric relationships from coppice structure of seven North American willow (Salix) species

Biomass yield and component coppice growth traits were assessed in up to 20 clones from seven native North American willow species, Salix amygdaloides (SAM), Salix bebbiana (BEB), Salix discolor (DIS), S eriocephala (ERI), Salix humilis (HUM), Salix interior (INT), and Salix nigra (NIG), established together in a clonally replicated common-garden field test. Aboveground mass, coppice stem number, stem length, and stem basal diameter measurements on up to 20 of the largest stems from 2-yr-old coppiced plants showed that ERI had the greatest aboveground mass, followed by INT, and then a close grouping of BEB, DIS, and HUM; the “tree” willows, AMY and NIG, had the lowest yields. The tree willows were not as prolific in coppice stem sprout production as were the shrub willows. The greatest number of stem sprouts was produced by ERI, with one coppice producing 67 2-yr-old stem sprouts, and ERI also showed an atypical, non-negative relationship between stem size and stem number; whereas the other six willows showed a varying but expected negative relationship between coppice stem size and stem number. Species differences in allometric relationships highlight the need to develop species-specific models for more accurate non-destructive biomass yield estimation.     

Gaston Planté and his invention of the lead-acid battery—The genesis of the first practical rechargeable battery

In 1860, the Frenchman Gaston Planté (1834-1889) invented the first practical version of a rechargeable battery based on lead-acid chemistry—the most successful secondary battery of all ages. This article outlines Planté’s fundamental concepts that were decisive for later development of practical lead-acid batteries. The ‘pile secondaire’ was indeed ahead its time in that an appropriate appliance for charging the accumulator was not available. The industrial success came after the invention of the Gramme machine. In 1879, Planté obtained acceptance for his work by publishing a book entitled Recherches sur l’Electricité. He never protected his inventions by patents, and spent much of his fortune on assisting impoverished scientists.     

Crystallite size and lattice strain of lithiated spinel material for rechargeable battery by X‐ray diffraction peak‐broadening analysis

High‐energy ball milling is performed on Li_1.1Mn_1.95Fe_0.05O₄ spinel material, synthesized by sol‐gel method for lithium rechargeable battery, at different durations to obtain nanopowders of finite size distributions. The powders are investigated by means of scanning electron microscopy, particle size distribution, and X‐ray diffraction (XRD) measurements. The structural analysis of the powders is performed to investigate the effect of milling on the particle size, crystallite size, and lattice strain. The scanning electron micrographs and size distribution measurements show that the particle size decreases with the increase in milling duration. The XRD results show that the widths of the diffraction peaks increase with the decrease of particle size (increase of milling duration). This broadening is analyzed according to Scherrer, Williamson‐Hall, and Halder‐Wagner methods. Peak broadening is attributed to contributions of crystallite size and lattice strain. While reducing the particle and crystallite sizes is desirable to achieve higher specific capacity and energy density of the battery active material, lattice strain leads to material degradation and a reduced capacity retention. Thus, when performing mechanical milling, lattice strain should be taken seriously into consideration to optimize the milling parameters and to enhance the materials electrochemical performance.     

A study of tri(ethylene glycol)-substituted trimethylsilane (1NM3)/LiBOB as lithium battery electrolyte

Silicon-based electrolyte has emerged as a primary candidate for the development of large lithium-ion batteries for electric vehicle (EV) and other systems in which safety is a primary consideration. Comparing to the electrolyte used in the conventional lithium-ion batteries, which are flammable, volatile, and highly reactive organic carbonate solvents, silicon-based electrolytes are thermally and chemically stable, less flammable and environmental benign. Tri(ethylene glycol)-substituted trimethylsilane (1NM3) was identified as a focus of investigation due to its high conductivity and low viscosity. We present the results of a systematic investigation of the 1NM3-based electrolytes with lithium bis(oxalate)borate (LiBOB) salt, including temperature dependent ionic conductivity and lithium cell performance. Lithium-ion cell with LiNi_1/3Co_1/3Mn_1/3O₂ as the positive electrode and MAG graphite as the negative electrode has shown excellent cyclability using 1NM3-LiBOB as electrolyte.     

全固态锂电池技术发展趋势与创新能力分析

科技创新加速推进全球能源格局朝向绿色、低碳、清洁、高效、智慧、多元方向转变,而高能量密度的储能器件是实现可再生能源消纳、促进终端应用电气化的关键.全固态锂电池作为下一代高能量密度主流技术方案受到业界广泛关注.本文综述了全固态锂电池中固态电解质研究现状,分析并提出了该技术面临的主要挑战和未来发展趋势.结合文献计量和专利计...     

Forecasting the value of battery electric vehicles compared to internal combustion engine vehicles: The influence of driving range and battery technology

Battery electric vehicles (BEVs) are now clearly a promising candidate to address the environmental problems that are associated with conventional internal combustion engine vehicles (ICEVs). Accordingly, governments in many countries have promoted consumer adoption of BEVs by providing financial incentives and automobile manufacturers are accelerating their efforts to develop BEVs. However, BEVs, unlike ICEVs, have not yet achieved mass market entry; continuing technological change is one way this barrier could be surmounted. The aim of this study is to assess and forecast whether and when design changes and technological improvements related to major challenges in driving range and battery cost will make the user value of BEVs greater than that of ICEVs. Specifically, we estimate the relative user value of BEVs and ICEVs resulting after design modifications are implemented to achieve different driving ranges by considering engineering trade-offs based on vehicle simulations. Then, we analyze when the BEV relative user value is expected to exceed that of ICEVs as energy density and cost of batteries improve due to ongoing technological changes. Our analysis demonstrates that the relative value of BEVs is lower than that of ICEVs because BEVs have high battery cost and high cost of time spent recharging them, despite featuring high torque, high fuel efficiency, and low fuel cost. Moreover, we found that the relative value differences between BEVs and ICEVs are found to be lower for high-performance large cars than low-performance compact cars because BEVs can achieve high acceleration performance more easily than can ICEVs. In addition, this study predicts that in approximately the year 2050, high-performance large BEVs could have a higher relative value than high-performance large ICEVs because of technological improvements in batteries; however, low-performance compact BEVs are still very likely to have significantly lower user values than will comparable ICEVs until well beyond the year 2050.     

Synthesis and properties of Schiff base Fe(II) complex

In our current study, Fe (II) complex with 4-4?-methylene bis (2,6-diethyl)aniline-3,5-di-tert-butylsalisilaldimine (HL1) ligand was synthesized by chemical method and the synthesized Fe (II) complex with HL1 ligand was named as Fe(L₁)₂ complex. Structural, morphological, electronic absorption and photovoltaic properties of Fe(L₁)₂ complex were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope, electronic absorption, and current density (J)–voltage (V) measurements, respectively. The obtained result from the J-V measurement shows that Fe(L₁)₂ complex synthesized by the chemical method can be used as a promising sensitizer for a dye-sensitized solar cell.     

Bilayered nanofilm of polypyrrole and poly(DMcT) for high-performance battery cathodes

Bilayered nanofilm electrodes made of polypyrrole (Ppy) and poly-2,5-dimercapto-1,3,4-thiadiazole (poly-DMcT) are produced by electrochemical means onto a carbon-fiber substrate, with the goal of preventing the loss of the electroactive mass of the disulfide and improving the electrode stability during the charge/discharge cycling process. Lightweight and high surface area composites are obtained by potentiostatically depositing a nanometric layer of Ppy onto a carbon fiber piece already supporting a layer of a potentiodynamically obtained poly(DMcT) film. The growth charge/mass ratio for the bilayered polymeric electrode is optimized, leading to a high electrochemical performance cathode with a stable specific capacity of ∼320 mA h g⁻¹ after 100 cycles.     

4种工业微生物产纤维素酶酶学特性的比较研究

文章对康宁木霉、绿色木霉、黑曲霉和里氏木霉表达纤维素酶的酶学特性进行了初步研究,结果表明,纤维素酶在pH低于5.0以及温度高于60℃条件下的稳定性较差;Fe2+和Mn2+的存在能够显著提高酶活性;Pb2+和Zn2+的存在严重抑制酶活性。黑曲霉表达纤维素酶活性高,是发酵产纤维素酶的较理想菌株。