An infrared spectroscopy study of the conformational evolution of the Bis(trifluoromethanesulfonyl)imide ion in the liquid and in the glass state

We measure the far-infrared spectrum of N,N-Dimethyl-N-ethyl-N-benzylammonium (DEBA) bis(trifluoromethanesulfonyl) imide (TFSI) ionic liquid (IL) in the temperature range between 160 and 307 K. Differential scanning calorimetry measurements indicate that such IL undergoes a glass transition around 210K. DFT calculations allow us to assign all the experimental absorptions to specific vibrations of the DEBA cation or of the two conformers of the TFSI anion. We find that the vibration frequencies calculated by means of the PBE0 functional are in better agreement with the experimental ones than those calculated at the B3LYP level, largely used for the attribution of vibration lines of ionic liquids. Experimentally we show that, in the liquid state, the relative concentrations of the two conformers of TFSI depend on temperature through the Boltzmann factor and the energy separation, ΔH, is found to be ≈2 kJ/mol, in agreement with previous calculations and literature. However, in the glassy state, the concentrations of the cis-TFSI and trans-TFSI remain fixed, witnessing the frozen state of this phase

A high-power and fast charging Li-ion battery with outstanding cycle-life

Electrochemical energy storage devices based on Li-ion cells currently power almost all electronic devices and power tools. The development of new Li-ion cell configurations by incorporating innovative functional components (electrode materials and electrolyte formulations) will allow to bring this technology beyond mobile electronics and to boost performance largely beyond the state-of-the-art. Here we demonstrate a new full Li-ion cell constituted by a high-potential cathode material, i.e. LiNi0.5Mn1.5O4, a safe nanostructured anode material, i.e. TiO2, and a composite electrolyte made by a mixture of an ionic liquid suitable for high potential applications, i.e. Pyr1,4PF6, a lithium salt, i.e. LiPF6, and standard organic carbonates. The final cell configuration is able to reversibly cycle lithium for thousands of cycles at 1000 mAg-1 and a capacity retention of 65% at cycle 2000. © 2017 The Author(s)

Understanding the impact of Fe-doping on the structure and battery performance of a Co-free Li-rich layered cathodes

A series of Co-free Li-rich layered oxides, Li1.24Mn0.62-xNi0.14FexO2 (x=0, 0.01, 0.02 and 0.03) has been synthetized by a self-combustion reaction. Fe doping affects either lattice structure and bonding as shown by the changes in the size of unit cell calculated from diffraction patterns and in the vibrational frequencies observed in Raman spectra. The electrochemical performance has been evaluated in a lithium cell by galvanostatic cycling: Doped samples show better capacity retention and minor decreases in the specific capacity (i. e., Li1.24Mn0.60Ni0.14Fe0.02O2 can supply a specific capacity of 235 mAhg−1 with 94 % of capacity retention after 150 cycles). These positive effects originated by alterations in the point defectivity (Ni3+ concentration, anionic and cationic vacancies), changes in the transport properties, as showed by Cyclic Voltammetry; as well as an improved structural resilience compared to the un-doped material in postmortem analyses. © 2023 The Authors. ChemElectroChem published by Wiley-VCH GmbH

Na-seawater battery technology integration with renewable energies: The case study of Sardinia Island

Europe has committed to net zero carbon dioxide emissions by 2050 to boost the clean energy transition. Renewable electricity will be the key energy medium for decarbonization and a huge increase in renewable energy sources (RES) exploitation is expected. Due to RES stochastic character, an extensive energy storage integration in the energy system is needed to avoid the mismatch between generation and demand profiles. Reactive metals are promising energy carriers and storage media characterized by high volumetric energy densities and circularity, due to ease of storage and transportation, material availability and low cost. Among them, sodium is a largely available element since it can be extracted from seawater and exploited through the innovative sodium-seawater battery (SWB). Sodium cations are transferred from SWB’s open cathode to the anode side during charging. Upon discharge, Na metal is oxidized to Na$^+$ ions, which are discarded in seawater. This study assesses the impact of SWB technology focusing on Sardinia Island as a case study. For short-term application, SWB integration to wave energy converters allows a potential reduction of greater than 85% of generated power fluctuations, largely improving the quality of power injected into the grid. Regarding the long-term scenario, SWBs implementation in the energy system allows coverage of the Sardinia annual energy demand thanks to the integration of ∼340,000 cubic meter of Na metal, corresponding to a 12-m height Na reservoir under 4 soccer fields. SWB application to Sardinia also produces CO$_2$ sequestration while covering ∼29% of desalinated water requirements for the Sardinian population

In-situ gelled electrolyte for lithium battery: Electrochemical and Raman characterization

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Electrolyte Measures to Prevent Polysulfide Shuttle in Lithium‐Sulfur Batteries

Lithium-sulfur (Li−S) batteries are recognized as one of the most promising technologies with the potential to become the next-generation batteries. However, to ensure Li−S batteries reach commercialization, complex challenges remain, among which the tailoring of an appropriate electrolyte is the most important. This review discusses the role of electrolytes in Li−S batteries, focusing on the main issues and solutions for the shuttle mechanism of polysulfides and the instability of the interface with lithium metal. Herein, we present a background on Li−S chemistry followed by the state-of-the-art electrolytes highlighting the different strategies undertaken with liquid and solid electrolytes

Structural and spectroscopic characterization of A nanosized sulfated TiO2 filler and of nanocomposite nafion membranes

A large number of nano-sized oxides have been studied in the literature as fillers for polymeric membranes, such as Nafion®. Superacidic sulfated oxides have been proposed and characterized. Once incorporated into polymer matrices, their beneficial effect on peculiar membrane properties has been demonstrated. The alteration of physical-chemical properties of composite membranes has roots in the intermolecular interaction between the inorganic filler surface groups and the polymer chains. In the attempt to tackle this fundamental issue, here we discuss, by a multi-technique approach, the properties of a nanosized sulfated titania material as a candidate filler for Nafion membranes. The results of a systematic study carried out by synchrotron X-ray diffraction, transmission electron microscopy, thermogravimetry, Raman and infrared spectroscopies are presented and discussed to get novel insights about the structural features, molecular properties, and morphological characteristics of sulphated TiO2 nanopowders and composite Nafion membranes containing different amount of sulfated TiO2 nanoparticles (2%, 5%, 7% w/w

Enhancing methane production from food waste fermentate using biochar. The added value of electrochemical testing in pre-selecting the most effective type of biochar

Background: Recent studies have suggested that addition of electrically conductive biochar particles is an effective strategy to improve the methanogenic conversion of waste organic substrates, by promoting syntrophic associations between acetogenic and methanogenic organisms based on interspecies electron transfer processes. However, the underlying fundamentals of the process are still largely speculative and, therefore, a priori identification, screening, and even design of suitable biochar materials for a given biotechnological process are not yet possible. Results: Here, three charcoal-like products (i.e., biochars) obtained from the pyrolysis of different lignocellulosic materials, (i.e., wheat bran pellets, coppiced woodlands, and orchard pruning) were tested for their capacity to enhance methane production from a food waste fermentate. In all biochar-supplemented (25 g/L) batch experiments, the complete methanogenic conversion of fermentate volatile fatty acids proceeded at a rate that was up to 5 times higher than that observed in the unamended (or sand-supplemented) controls. Fluorescent in situ hybridization analysis coupled with confocal laser scanning microscopy revealed an intimate association between archaea and bacteria around the biochar particles and provided a clear indication that biochar also shaped the composition of the microbial consortium. Based on the application of a suite of physico-chemical and electrochemical characterization techniques, we demonstrated that the positive effect of biochar is directly related to the electron-donating capacity (EDC) of the material, but is independent of its bulk electrical conductivity and specific surface area. The latter properties were all previously hypothesized to play a major role in the biochar-mediated interspecies electron transfer process in methanogenic consortia. Conclusions: Collectively, these results of this study suggest that for biochar addition in anaerobic digester operation, the screening and identification of the most suitable biochar material should be based on EDC determination, via simple electrochemical tests. © 2017 The Author(s)

Production of nanostructured electrodes from spent Lithium ion batteries and their application in new energy storage devices

The present work is aimed at demonstrating the potentiality of lithium ion batteries recycling through the production of high added value nanostructured material. Nanostructured electrodic materials were synthesized starting from waste lithium ion batteries (LIBs). Firstly, the metals contained in the electrodic powder of exhausted LIBs were extracted by acid-reducing leaching. After filtration, metals rich solution was separated from graphite. Nanoparticles- based electrodes were produced by controlled precipitation and subsequent calcination of metals in order to obtain nanoparticles of LiNi1/3Co1/3Mn1/3O2, one of the most employed LIBs cathodic material. Cathodic materials synthesized starting from waste LIBs and from high grade synthetic reagents were compared after their characterization by SEM, EDX and XRD. The electrochemical performance of the electrodes was evaluated by galvanostatic cycling the electrodes in a lithium half-cell. Remarkably, the electrochemical performances obtained with the electrodes produced by the recovery of metals are close to those recorded using electrodes produced by synthetic reagents. © 2020 Author(s)

Room-temperature synthesis of 2D-Ti3C2Tx nano-sheets by organic base treatment

The growing demand for improved electrochemical performance in energy storage systems has stimulated research into advanced two-dimensional (2D) materials for electrodes. In this work, we obtain a layered MXene compound by exfoliating a titanium aluminum carbide precursor using tetramethylammonium hydroxide (TMAOH) ions in a full room temperature process followed by manual shaking. The hexagonal crystal structure and composition of the layered materials are characterized using different techniques. X-Ray diffraction shows the formation of 2D nano-sheets before and after the TMAOH treatment via its characteristic (002) diffraction peak, bringing to light an increase in the interlayer spacing after treatment. Scanning electron microscopy images confirm the layered morphology, whose composition is determined by energy dispersive x-ray analysis for the bulk material and by x-ray photoelectron spectroscopy for the surface of the obtained compounds. This study demonstrates a promising route to enhance delamination of this MXene 2D material in a low-cost room-temperature approach