Ionic liquids containing tricyanomethanide anions: physicochemical characterisation and performance as electrochemical double-layer capacitor electrolytes

We investigated the use of fluorine free ionic liquids (ILs) containing the tricyanomethanide anion ([C(CN)3]) as an electrolyte in electrochemical double-layer capacitors (EDLCs). Three cations were used; 1-butyl-3-methylimidazolium ([Im1,4]), N-butyl-N-methylpyrrolidinium ([Pyr1,4]) and N-butyl-N-methylpiperidinium ([Pip1,4]). Their physicochemical properties are discussed alongside with their performance as electrolytes. We found that the cyano-based ILs present higher ionic conductivity (9.4, 8.7 and 4.2 mS cm−1 at 25 °C for [Im1,4], [Pyr1,4] and [Pip1,4], respectively) than the widely studied IL containing the bis(trifluoromethylsulfonyl)imide anion, namely [Pyr1,4][Tf2N] (2.7 mS cm−1 at 25 °C). Of the three ILs investigated, [Pip1,4][C(CN)3] presents the widest electrochemical stability window, 3.0 V, while [Pyr1,4][C(CN)3] is stable up to 2.9 V and its [Tf2N] analogue can operate at 3.5 V. Despite operating at a lower voltage, [Pyr1,4][C(CN)3] EDLC is capable of delivering up to 4.5 W h kg−1 when operating at high specific power of 7.2 kW kg−1, while its [Pyr1,4][Tf2N] counterpart only delivered 3.0 W h kg−1 when operated at similar power

A review on Li-S batteries as a high efficiency rechargeable lithium battery

Energy production and storage are critical research domains where the demands for improved energy devices and the requirement for greener energy resources are increasing. There is particularly intense interest in Lithium (Li)-ion batteries for all kinds of electrochemical energy storage. Li-ion batteries are currently the primary energy storage devices in the communications, transportation and renewable-energy sectors. However, scaling up the Li-ion battery technology to meet current increasing demands is still problematic and issues such as safety, costs, and electrode materials with higher performance are under intense investigation. The Li-sulfur (S) battery is a promising electrochemical system as a high-energy secondary battery, particularly for large-scale applications, due to its low cost, theoretically large specific capacity, theoretically high specific energy, and its ecofriendly footprint. The Li-S battery exhibits excellent potential and has attracted the attention of battery developers in large scale production in recent years. This review aims to highlight recent advances in the Li-S battery, providing an overview of the Li-ion battery applications in energy storage, then detailing the challenges facing Li-S battery and current applied strategies for improvement in its efficiency

Mosquito Species diversity (Diptera: Culicidae) and larval habitat characteristics in

Background & aim: Malaria is considered to be a major health problem in many countries. The aim of this study was to identify new species of Culicidae larval habitat of Anopheles and to determine their distribution in the Kohgiloye and Boyer province, Iran. Methods: In the present cross-sectional study, the larval habitats of three cities (including Yasuj, Dehdasht and Gachsaran) of Kohgiloye and Boyer Ahmad province was conducted during 2012. Samples were collected with a scoop by ladle handling for Entomology. The collected Larvae were canned in Lactophenol solution with features and code related transferred to entomology laboratory of Tehran University of Medical Sciences. The microscopic slides were prepared using a Lekidofore solution and were identified with key valid diagnosis. The data were analyzed by SPSS software version 11.5. Results: A total of 1043 samples of mosquito larvae were identified in different parts of Kohgiloyeh and Boyerahmad in 2 genera and 12 species. These identified species were: Anopheles ( Cellia)superpictus Grassi, An.(Cel.)fluviatilis James, An.(Cel.)dthali Patton, An.(Cel.)turkhudi Liston, An.(Cel.)stephensi Liston, An.(Cel.) subpictus Grassi, An.(Anopheles)sacharovi Favre, Cx.(Cux.)theileri Theobad, Cx.(Cux.)sitiens Wiedemann, Cx.( Cux.)pipens Linnaeus, Cx.(Cux.)pusillus Macquart, Cx.(Cux.)perxiguus Theobald. Culex pipens larvae was predominant and Cx.(Cux.)sitiens, Cx.(Cux.)perxiguus, An.sacharovi were found as the lowest larvae . Culicidae Culex mosquito larvae was the highest and the lowest species were Cx.(Cux.)sitiens, Cx.(Cux.)perxiguus, An.sacharovi. Conclusion:Culex pipens was the dominant species. Exclusive molecular and morphological studies will be essential to identify the malaria vectors, An.stephensi complex and An.superpictus complex in this are

In Situ Synchrotron XRD and sXAS Studies on Li-S Batteries with Ionic-Liquid and Organic Electrolytes

Lithium-sulfur (Li-S) batteries are a promising technology capable of reaching high energy density of 500-700 Wh kg-1, however the practically achievable performance is still lower than this value. This hindrance can be attributed to a lack of understanding of the fundamental electrochemical processes during Li-S battery cycling, in particular the so-called redox shuttle effect which is due to the relatively high solubility of polysulfide intermediates in the electrolyte. Herein, the effects of LiNO3 as an additive as well as C4mpyr-based ionic liquids (ILs) in electrolyte formulations for Li-S cells are analysed using in situ X-ray powder diffraction (XRD) and ex situ soft X-ray absorption spectroscopy (sXAS) techniques. Whilst LiNO3 is known for its protective properties on the lithium anode in Li-S cells, our studies have provided further evidence for suppression of Li2S deposition when using LiNO3 as an additive, as well as affecting the solid electrolyte interphase (SEI) layer at a molecular level. Moreover, the detected sulfur species on the surface of the anode and cathode, after a few cycles are compared for IL and organic-based electrolytes

Suppressed Polysulfide Crossover in Li–S Batteries through a High-Flux Graphene Oxide Membrane Supported on a Sulfur Cathode

Utilization of permselective membranes holds tremendous promise for retention of the electrode-active material in electrochemical devices that suffer from electrode instability issues. In a rechargeable Li–S batterya strong contender to outperform the Li-ion technologymigration of lithium polysulfides from the sulfur cathode has been linked to rapid capacity fading and lower Coulombic efficiency. However, the current approaches for configuring Li–S cells with permselective membranes suffer from large ohmic polarization, resulting in low capacity and poor rate capability. To overcome these issues, we report the facile fabrication of a high-flux graphene oxide membrane directly onto the sulfur cathode by shear alignment of discotic nematic liquid crystals of graphene oxide (GO). In conjunction with a carbon-coated separator, the highly ordered structure of the thin (∼0.75 μm) membrane and its inherent surface charge retain a majority of the polysulfides, enabling the cells to deliver very high initial discharge capacities of 1063 and 1182 mAh g_electrode^–1 for electrodes with 70 and 80% sulfur content, respectively, at the practical 0.5 C rate. The very high sulfur utilization and impressive capacity retentions of the high sulfur content electrodes result in some of the highest performance metrics in the literature of Li–S (<i>e.g.</i>, electrode capacity of 835 mAh g_electrode^–1 after 100 cycles at 0.5 C with a sulfur content of 80%). We show that the structural order of the shear-aligned GO membrane is key in maintaining good kinetics of the charge transfer processes in Li–S batteries