Gelatine based gel polymer electrolyte towards more sustainable Lithium-Oxygen batteries

The lithium-oxygen battery has attracted wide interest thanks to its very high theoretical energy density, and as such it is considered by many as a valid battery of the future candidate. However, the challenges in its practical application are many, such as liquid electrolyte evaporation in semi-open systems, as well as solvents instability in a highly oxidizing environment. In this work, we propose to use gelatin, from cold water fish skin, a waste from the fishing industry, to prepare an efficient gel electrolyte for future Li-O2 battery applications. After a single step methacrylation in water, methacrylated gelatine is directly cross-linked in presence of liquid electrolyte through UV- initiated radical polymerization. The obtained gel polymer electrolytes present good thermal and mechanical properties, good electrochemical stability against Li metal and ionic conductivities as high as 2.51 mS cm−1 at room temperature. the Li-O2 cells assembled with this bio-renewable gel polymer electrolytes were able to perform more than 100 cycles at 0.1 mA cm−2, under constant O2 flow, at room temperature and at a fixed capacity of 0.2 mAh cm−2. Cathodes post- mortem analysis confirmed that the cross-linked gelatin matrix was able to slow down solvent degradation and therefore enhance the cell reversibility

Clustering in gravitating N-body systems

We study gravitational clustering of mass points in three dimensions with random initial positions and periodic boundary conditions (no expansion) by numerical simulations. Correlation properties are well defined in the system and a sort of thermodynamic limit can be defined for the transient regime of cluste ring. Structure formation proceeds along two paths: (i) fluid-like evolution of density perturbations at large scales and (ii) shift of the granular (non fluid) properties from small to large scales. The latter mechanism finally dominates at all scales and it is responsible for the self-similar characteristics of the clustering.Comment: 7 pages, 3 figures. Accepted for publication in Europhys. Let

Li+ Insertion in Nanostructured TiO2 for Energy Storage

Nanostructured materials possess unique physical-chemical characteristics and have attracted much attention, among others, in the field of energy conversion and storage devices, for the possibility to exploit both their bulk and surface properties, enabling enhanced electron and ion transport, fast diffusion of electrolytes, and consequently high efficiency in the electrochemical processes. In particular, titanium dioxide received great attention, both in the form of amorphous or crystalline material for these applications, due to the large variety of nanostructures in which it can be obtained. In this paper, a comparison of the performance of titanium dioxide prepared through the oxidation of Ti foils in hydrogen peroxide is reported. In particular, two thermal treatments have been compared. One, at 150 °C in Ar, which serves to remove the residual hydrogen peroxide, and the second, at 450 °C in air. The material, after the treatment at 150 °C, results to be not stoichiometric and amorphous, while the treatment at 450 °C provide TiO2 in the anatase form. It turns out that not-stoichiometric TiO2 results to be a highly stable material, being a promising candidate for applications as high power Li-ion batteries, while the anatase TiO2 shows lower cyclability, but it is still promising for energy-storage devices

Mean-field model of the ferromagnetic ordering in the superconducting phase of ErNi_2B_2C

A mean-field model explaining most of the details in the magnetic phase diagram of ErNi_2B_2C is presented. The low-temperature magnetic properties are found to be dominated by the appearance of long-period commensurate structures. The stable structure at low temperatures and zero field is found to have a period of 40 layers along the a direction, and upon cooling it undergoes a first-order transition at T_C = 2.3 K to a different 40-layered structure having a net ferromagnetic component of about 0.4 mu_B/Er. The neutron-diffraction patterns predicted by the two 40-layered structures, above and below T_C, are in agreement with the observations of Choi et al.Comment: 4 pages, 3 figures (Revtex4

Correction to: New eco-friendly low-cost binders for Li-ion anodes

The article New eco-friendly low-cost binders for Li-ion anodes, written by D. Versaci, R. Nasi, U. Zubair, J. Amici, M. Sgroi, M. A. Dumitrescu, C. Francia, S. Bodoardo and N. Penazzi, was originally published electronically on the publisher's internet portal (currently SpringerLink)

The left superior temporal gyrus is a shared substrate for auditory short-term memory and speech comprehension: evidence from 210 patients with stroke

Competing theories of short-term memory function make specific predictions about the functional anatomy of auditory short-term memory and its role in language comprehension. We analysed high-resolution structural magnetic resonance images from 210 stroke patients and employed a novel voxel based analysis to test the relationship between auditory short-term memory and speech comprehension. Using digit span as an index of auditory short-term memory capacity we found that the structural integrity of a posterior region of the superior temporal gyrus and sulcus predicted auditory short-term memory capacity, even when performance on a range of other measures was factored out. We show that the integrity of this region also predicts the ability to comprehend spoken sentences. Our results therefore support cognitive models that posit a shared substrate between auditory short-term memory capacity and speech comprehension ability. The method applied here will be particularly useful for modelling structure–function relationships within other complex cognitive domains

Designing a double-coated cathode with high entropy oxides by microwave-assisted hydrothermal synthesis for highly stable Li–S batteries

Nowadays, Li-S batteries are considered as one of the most promising alternatives to Li-ion technology in the near future, thanks to their high specific capacity and their significantly lower environmental impact and production costs. Consequently, many efforts have been directed to tackle with the inherent issues that affect Li-S batteries. One of the main problems is the so-called shuttle effect, which basically entails the unwanted migration of lithium polysulfides (LiPSs) from the cathode to the anode side, causing the degradation of the cell. Here, we report an effective strategy to restrain the shuttle effect and increase the kinetics at the cathode of the lithium-sulfur (Li-S) battery. A functional layer including high entropy oxides (HEO) coated onto the sulfur cathode allows to exploit the HEOs capability as promoter catalysts for the conversion of LiPSs. Pure HEO powders are synthesized by fast, highly efficient microwave irradiation, followed by heat treatment at 930 degrees C. The formation of highly crystalline HEO is confirmed by X-ray diffraction analysis. The LiPSs adsorption capability of HEO is evaluated by UV-vis and X-ray photoelectron spectroscopy analyses. The effect of the HEO-coated sulfur cathode on the electrochemical performance of the Li-S battery is studied by cyclic voltammetry and galvanostatic charge/discharge. The cell with double-coated cathode delivers an initial discharge capacity of 1173 mAh/g at C/10 with 45% capacity retention over 500 cycles at C/5, approaching similar to 99% coulombic efficiency.[GRAPHICS]

Enhanced insulin sensitivity in skeletal muscle and liver by physiological overexpression of SIRT6

Objective: Available treatment for obesity and type 2 diabetes mellitus (T2DM) is suboptimal. Thus, identifying novel molecular target(s) exerting protective effects against these metabolic imbalances is of enormous medical significance. Sirt6 loss- and gain-of-function studies have generated confounding data regarding the role of this sirtuin on energy and glucose homeostasis, leaving unclear whether activation or inhibition of SIRT6 may be beneficial for the treatment of obesity and/or T2DM. Methods: To address these issues, we developed and studied a novel mouse model designed to produce eutopic and physiological overexpression of SIRT6 (Sirt6BAC mice). These mutants and their controls underwent several metabolic analyses. These include whole-blood reverse phase high-performance liquid chromatography assay, glucose and pyruvate tolerance tests, hyperinsulinemic-euglycemic clamp assays, and assessment of basal and insulin-induced level of phosphorylated AKT (p-AKT)/AKT in gastrocnemius muscle. Results: Sirt6BAC mice physiologically overexpress functionally competent SIRT6 protein. While Sirt6BAC mice have normal body weight and adiposity, they are protected from developing high-caloric-diet (HCD)-induced hyperglycemia and glucose intolerance. Also, Sirt6BAC mice display increased circulating level of the polyamine spermidine. The ability of insulin to suppress endogenous glucose production was significantly enhanced in Sirt6BAC mice compared to wild-type controls. Insulin-stimulated glucose uptake was increased in Sirt6BAC mice in both gastrocnemius and soleus muscle, but not in brain, interscapular brown adipose, or epididymal adipose tissue. Insulin-induced p-AKT/AKT ratio was increased in gastrocnemius muscle of Sirt6BAC mice compared to wild-type controls. Conclusions: Our data indicate that moderate, physiological overexpression of SIRT6 enhances insulin sensitivity in skeletal muscle and liver, engendering protective actions against diet-induced T2DM. Hence, the present study provides support for the anti-T2DM effect of SIRT6 and suggests SIRT6 as a putative molecular target for anti-T2DM treatment

Magnetic Phase Diagram of GdNi2B2C: Two-ion Magnetoelasticity and Anisotropic Exchange Couplings

Extensive magnetization and magnetostriction measurements were carried out on a single crystal of GdNi2B2C along the main tetragonal axes. Within the paramagnetic phase, the magnetic and strain susceptibilities revealed a weak anisotropy in the exchange couplings and two-ion tetragonal-preserving alpha-strain modes. Within the ordered phase, magnetization and magnetostriction revealed a relatively strong orthorhombic distortion mode and rich field-temperature phase diagrams. For H//(100) phase diagram, three field-induced transformations were observed, namely, at: Hd(T), related to the domain alignment; Hr(T), associated with reorientation of the moment towards the c-axis; and Hs(T), defining the saturation process wherein the exchange field is completely counterbalanced. On the other hand, For H//(001) phase diagram, only two field-induced transformations were observed, namely at: Hr(T) and Hs(T). For both phase diagrams, Hs(T) follows the relation Hs[1-(T/Tn)^2]^(1/2)kOe with Hs(T-->0)=128.5(5) kOe and Tn(H=0)=19.5 K. In contrast, the thermal evolution of Hr(T) along the c-axis (much simpler than along the a-axis) follows the relation Hr[1-T/Tr]^(1/3) kOe where Hr(T-->0)=33.5(5) kOe and Tr(H=0)=13.5 K. It is emphasized that the magnetoelastic interaction and the anisotropic exchange coupling are important perturbations and therefore should be explicitly considered if a complete analysis of the magnetic properties of the borocarbides is desired