Dimethyl sulfoxide as a function additive on halogen-free electrolyte for magnesium battery application.

Practical Mg batteries still face significant challenges in their development, like the lack of simple compatible electrolytes, self-discharge, the rapid passivation of the Mg anode, and the slow conversion reaction pathway. Here, we propose a simple halogen-free electrolyte (HFE) based on magnesium nitrate (Mg(NO3)2), magnesium triflate Mg(CF3SO3)2, and succinonitrile (SN) dissolved in acetonitrile (ACN)/tetraethylene glycol dimethyl ether (G4) cosolvents, with dimethyl sulfoxide as a functional additive. The addition of DMSO to the HFE changes the interfacial structure at the magnesium anode surface and facilitates the transport of magnesium ions. The as-prepared electrolyte shows high conductivity (σ b = 4.48 × 10-5, 6.52 × 10-5 and 9.41 × 10-5 S cm-1 at 303, 323, and 343 K, respectively) and a high ionic transference number (tmg +2 = 0.91/0.94 at room temperature/55 °C) for the matrix containing 0.75 ml of DMSO. Also, the cell with 0.75 ml of DMSO shows high oxidation stability, a very low overpotential, and steady Mg stripping/plating up to 100 h. Postmortem analysis of pristine Mg and Mg anodes extracted from disassembled Mg/HFE/Mg and Mg/HFE_0.75 ml DMSO/Mg cells after stripping/plating reveals the role of DMSO in improving Mg-ion passage through HFE by evolving the anode/electrolyte interface at the Mg surface. Further optimization of this electrolyte is expected to achieve excellent performance and good cycle stability when applied to the magnesium battery in future work.

Relationship between thoracic kyphosis and neural axis abnormalities in patients with adolescent idiopathic scoliosis.

PURPOSE: Previous studies have suggested an association between increased thoracic kyphosis and neural axis abnormalities in patients with adolescent idiopathic scoliosis (AIS). However, the basis for this finding is unclear, and this association has been mainly noted in retrospective studies on a non-consecutive series of patients. The purpose of this study was to assess the relationship between thoracic kyphosis and neural axis abnormalities in patients with AIS. METHODS: We studied a consecutive series of AIS patients treated with spinal fusion. Thoracic kyphosis (T2 to T12) was measured from preoperative lateral radiographs. All patients underwent a spine magnetic resonance imaging (MRI) prior to surgery, and MRI reports were reviewed to determine the presence of neural axis abnormalities. Statistical analyses included descriptive statistics and chi-squared analysis. RESULTS: This study included 210 patients with AIS. There were no significant differences in age or gender between patients with thoracic hypokyphosis (kyphosis < 20°), normal thoracic kyphosis (kyphosis 20° to 40°) and thoracic hyperkyphosis (kyphosis > 40°) (p > 0.05). Neural axis abnormalities were present in 17.9% of patients with thoracic hypokyphosis, 9.8% of patients with normal thoracic kyphosis and 13.6% of patients with thoracic hyperkyphosis (p = 0.60). There were no significant differences in rates of Chiari malformation, syrinx, intra-spinal masses and other central nervous system abnormalities between groups (p > 0.05). CONCLUSIONS: Thoracic kyphosis was not associated with neural axis abnormalities in our consecutive series of patients with AIS. Increased thoracic kyphosis may not be a reliable indicator for the presence of neural axis abnormalities in patients with AIS. LEVEL OF EVIDENCE: IV.

Ion transport properties of magnesium bromide/dimethyl sulfoxide non-aqueous liquid electrolyte.

Nonaqueous liquid electrolyte system based dimethyl sulfoxide DMSO and magnesium bromide (MgBr2) is synthesized via 'Solvent-in-Salt' method for the application in magnesium battery. Optimized composition of MgBr2/DMSO electrolyte exhibits high ionic conductivity of 10(-2) S/cm at ambient temperature. This study discusses different concentrations from 0 to 5.4 M of magnesium salt, representing low, intermediate and high concentrations of magnesium salt which are examined in frequency dependence conductivity studies. The temperature dependent conductivity measurements have also been carried out to compute activation energy (Ea ) by least square linear fitting of Arrhenius plot: 'log σ - 1/T. The transport number of Mg(2+) ion determined by means of a combination of d.c. and a.c. techniques is ∼0.7. A prototype cell was constructed using nonaqueous liquid electrolyte with Mg anode and graphite cathode. The Mg/graphite cell shows promising cycling.

Preparation and physical properties of (PVA)0.7(NaBr)0.3(H3PO4) x M solid acid membrane for phosphoric acid - Fuel cells.

A solid acid membranes based on poly (vinyl alcohol) (PVA), sodium bromide (NaBr) and phosphoric acid (H3PO4) were prepared by a solution casting method. The morphological, IR, electrical and optical properties of the (PVA)0.7(NaBr)0.3(H3PO4) x M solid acid membranes where x = 0.00, 0.85, 1.7, 3.4, 5.1 M were investigated. The variation of film morphology was examined by scanning electron microscopy (SEM) studies. FTIR spectroscopy has been used to characterize the structure of polymer and confirms the complexation of phosphoric acid with host polymeric matrix. The temperature dependent nature of ionic conductivity and the impedance of the polymer electrolytes were determined along with the associated activation energy. The ionic conductivity at room temperature was found to be strongly depends on the H3PO4 concentration which it has been achieved to be of the order 4.3 × 10(-3) S/cm at ambient temperature. Optical measurements showed a decrease in optical band gap and an increase in band tail width with the increase of phosphoric acid. The data shows that the (PVA)0.7(NaBr)0.3(H3PO4) x M solid acid membrane is promising for intermediate temperature phosphoric acid fuel cell applications.

Electrical conduction and dielectric relaxation in p-type PVA/CuI polymer composite.

PVA/CuI polymer composite samples have been prepared and subjected to characterizations using FT-IR spectroscopy, DSC analysis, ac spectroscopy and dc conduction. The FT-IR spectral analysis shows remarkable variation of the absorption peak positions whereas DSC illustrates a little decrease of both glass transition temperature, Tg , and crystallization fraction, χ, with increasing CuI concentration. An increase of dc conductivity for PVA/CuI nano composite by increasing CuI concentration is recoded up to 15 wt%, besides it obeys Arhenuis plot with an activation energy in the range 0.54-1.32 eV. The frequency dependence of ac conductivity showed power law with an exponent 0.33 < s < 0.69 which predicts hopping conduction mechanism. The frequency dependence of both dielectric permittivity and dielectric loss obeys Debye dispersion relations in wide range of temperatures and frequency. Significant values of dipole relaxation time obtained which are thermally activated with activation energies in the range 0.33-0.87 eV. A significant value of hopping distance in the range 3.4-1.2 nm is estimated in agreement with the value of Bohr radius of the exciton.