Investigating non-fluorinated anions for sodium battery electrolytes based on ionic liquids

In order for sodium batteries to become a safe, lower cost option for large scale energy storage, minimising the price of all components is important. We report here on the application of a pyrrolidinium room temperature ionic liquid comprising the dicyanamide anion as a successful electrolyte system for sodium metal batteries that does not contain expensive fluorinated species. The effects of plating/stripping of sodium from Na metal electrodes has been investigated in a symmetrical Na|electrolyte|Na configuration at a current density of 10 μA cm−2. Comparisons are drawn to reference organic electrolytes comprising propylene carbonate-fluoroethylene carbonate. Residual water molecules in the ionic liquid electrolyte are observed to have a significant effect upon the surface film and subsequent favourable plating/stripping behaviour of symmetrical cells and this is explored in detail. An increase of the moisture content from 90 ppm to 400 ppm impedes both electrodeposition and electrodissolution of the Na+/Na. This is investigated at Ni electrodes using cyclic voltammetry at different Na+-salt concentrations to further understand the mechanism

The influence of water and metal ions on the transport properties of trihexyl(tetradecyl)phosphonium chloride

A recent study indicated that the water-saturated ionic liquid (IL) trihexyl(tetradecyl)phosphonium chloride ([P6,6,6,14][Cl]) provided a viable electrolyte for a Mg-air battery. However, there is limited literature on the properties of IL-water mixtures as battery electrolytes. The physical properties of [P6,6,6,14][Cl] were studied with the addition of both water and metal salts (MgCl2 and LiCl) using conductivity and self-diffusion coefficient measurements. The conductivity of the samples at low water concentrations is surprisingly enhanced by the addition of the metal salt, contrary to lithium IL electrolytes. It was also found that the conductivity of the IL was increased by an order of magnitude by saturation with water. NMR diffusion measurements were used to probe the behaviour of both the cation and the water in the mixtures. It was found that the addition of metal salts to the water-saturated [P6,6,6,14][Cl] did not affect the transport properties of the water or cation.<br /

Deletions, repeat-induced point mutations and amino acid substitutions drive evolution of linked effectors in a fungal plant pathogen

Pathogen effectors, molecules that include small secreted proteins such as avirulence proteins, facilitate infection or induce defence responses by plants. We report the first large scale study of evolutionary processes affecting linked effector-like genes in a fungal plant pathogen. Mutations affecting seven genes and four single copy non-coding regions located in a 520 kb repetitive element-rich region of Leptosphaeria maculans, a pathogen of Brassica napus (canola) are described. Two genes are avirulence genes, AvrLm1 and AvrLm6, which are complementary to B. napus resistance genes, Rlm1 and Rlm6. Analyses of 295 Australian isolates showed that deletions, Repeat-Induced Point (RIP) mutations and/or non-RIP derived amino acid substitutions account for rapid evolution of four small secreted proteins. RIP was confined to three genes and two other single copy regions and appeared to have ‘leaked’ from flanking repetitive sequences. The RIP alleles were monophyletic and present only in isolates collected after 2004, the year when canola cultivars with resistance conferred by Rlm1 suffered severe yield losses. This co-incided with a large increase in the frequency of isolates with virulence alleles of AvrLm1 and AvrLm6, even though the canola cultivars lacked Rlm6. Evolution of these two effectors thus appears to be influenced both by the genomic environment (flanking repetitive elements) and by selection pressure from extensive sowing of crop varieties with resistance genes complementary to the avirulence effector gene