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[en] Herein, a new and facile synthesis of a tin-carbon nanocomposite and its electrochemical characterization is presented. Tin nanoparticles were embedded in micron-sized carbonaceous particles, thus successfully preventing the aggregation of tin nanoparticles and buffering the occurring volume strain, which accompanies the reversible (de-)alloying process. Such active material presents specific capacities of around 440 and 390 mAh g−1 for applied specific currents of 0.1 and 0.2 A g−1, respectively, as lithium-ion anode using environmentally friendly and cost-efficient carboxymethyl cellulose as binder. Even more remarkably, at very high specific currents of 2, 5, and 10 A g−1, electrodes based on this composite still offer specific capacities of about 280, 240, and 187 mAh g−1, respectively. In addition, this tin-carbon nanocomposite appears highly promising as anode material for sodium-ion batteries, showing very stable cycling performance in a suitable potential range, and specific capacities of more than 180, 150, 130, and 90 mAh g−1 for an applied specific current of 12.2, 122, 244, and 610 mA g−1, respectively, thus highlighting the high versatility of this composite active material for both Li-ion and Na-ion battery technologies
[en] Highlights: • A template assisted sol-gel method is used to prepare Na0.44MnO2 nanoplates. • The Na0.44MnO2 nanoplates with high purity show good electrochemical performance. • The nanoplates with limited crystal growth along  facilitate Na-ion diffusion. Monocrystalline orthorhombic Na0.44MnO2 nanoplate as a potential cathode material for sodium-ion batteries has been synthesized by a template-assisted sol-gel method. It exhibits high crystallinity, pure phase and homogeneous size distribution. During the synthesis, acidic and reductive conditions are applied to limit the production of unfavorable Birnessite phase in the precursor, and colloidal polystyrene is included to avoid morphology collapse during the gel formation and particle elongation in one direction. The decompositions of polystyrene and citric acid during high temperature firing offer a reductive carbothermal condition which can suppress the formation of unidimensional particles, and limit particle growth along the  direction. As a consequence, the material delivers 96 mAh g−1 discharge capacity at 10 C (86% of 0.1 C capacity) and maintains 97.8% capacity after 100 cycles at 0.5 C. Such superior rate capability and cycling stability of this material are among the best to date, suggesting its great interest in practical applications.
[en] This paper examines the behaviour of lithium polymer electrolytes based on aromatic sulfonamide salts tailored to optimize negative charge delocalization through the aromatic ring and up to the nitro substituents located in the para and para/ortho positions of the nitrogen of the sulfonamide anion. For the first time, lithium salt dissociation has been connected to the Σ+ value. Thanks to the tailoring of these anions and to this physico-chemical approach it has been possible to show that resonance electron-withdrawing effects, as opposed to inductive ones, are decisive in reaching high conductivities in aprotic polymer electrolytes. Moreover the dissociation enhancement that can be expected, using the Σ+ value of NO2, from the introduction of an additional nitro group, is in good agreement with the conductivity enhancement.
[en] The oxygen redox reaction (ORR) in pyrrolidinium-based ionic liquids (ILs) without and with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is investigated at different temperatures for lithium/oxygen battery application. Results obtained by cyclic voltammetry, rotating disk electrode, and ultramicroelectrode potential steps at glassy carbon are reported and discussed in relation to the physical–chemical properties of the investigated ILs. Diffusion coefficients and solubility of oxygen in the ILs and tentative values of ORR heterogeneous rate constant in ILs without LiTFSI are reported. The effect of lithium salt on the ORR in IL is also discussed in view of lithium/oxygen battery application.