PVDF-HFP Based, Quasi-Solid Nanocomposite Electrolytes for Lithium Metal Batteries.

Composite polymer electrolytes are systems of choice for future solid-state lithium metal batteries (LMBs). Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is among the most interesting matrices to develop new generation quasi-solid electrolytes (QSEs). Here it is reported on nanocomposites made of PVDF-HFP and pegylated SiO2 nanoparticles. Silica-based hybrid nanofillers are obtained by grafting chains of poly(ethylene glycol) methyl ether (PEG) with different molecular weight on the surface of silica nanoparticles. The functionalized nanofiller improves the mechanical, transport and electrochemical properties of the QSEs, which show good ionic conductivity values and high resistance against dendrite penetration, ensuring boosted long and safe device operation. The most promising result is obtained by dispersing 5 wt% of SiO2 functionalized with short PEG chains (PEG750, Mw = 750 g mol-1) in the PVDF-HFP matrix with an ease solvent-casting procedure. It shows ionic conductivity of 0.1 mS cm-1 at 25 °C, more than 250 h resistance to stripping/plating, and impressive results during cycling tests in LMB with LiFePO4 cathode.

Normalization of charge/discharge time vs. current rate diagrams for rechargeable batteries.

It is vital to comprehend the charge/discharge behaviors of batteries to improve their properties. In this paper, we normalize the electrode materials' behaviors according to the time of the process to allow a rational comparison between different materials and batteries.

Unveiling the Role of PEO-Capped TiO2 Nanofiller in Stabilizing the Anode Interface in Lithium Metal Batteries.

Lithium metal batteries (LMBs) will be a breakthrough in automotive applications, but they require the development of next-generation solid-state electrolytes (SSEs) to stabilize the anode interface. Polymer-in-ceramic PEO/TiO2 nanocomposite SSEs show outstanding properties, allowing unprecedented LMBs durability and self-healing capabilities. However, the mechanism underlying the inhibition/delay of dendrite growth is not well understood. In fact, the inorganic phase could act as both a chemical and a mechanical barrier to dendrite propagation. Combining advanced in situ and ex situ experimental techniques, we demonstrate that oligo(ethylene oxide)-capped TiO2, although chemically inert toward lithium metal, imparts SSE with mechanical and dynamical properties particularly favorable for application. The self-healing characteristics are due to the interplay between mechanical robustness and high local polymer mobility which promotes the disruption of the electric continuity of the lithium dendrites (razor effect).

A physico-chemical investigation of highly concentrated potassium acetate solutions towards applications in electrochemistry.

Water-in-salt solutions, i.e. solutions in which the amount of salt by volume or weight is larger than that of the solvent, are attracting increasing attention in electrochemistry due to their distinct features that often include decomposition potentials much higher than those of lower concentration solutions. Despite the high solubility of potassium acetate (KAC) in water at room temperature (up to 25 moles of salt per kg of solvent), the low cost, and the large availability, the use of highly concentrated KAC solutions is still limited to a few examples in energy storage applications and a systematic study of their physical-chemical properties is lacking. To fill this gap, we have investigated the thermal, rheological, electrical, electrochemical, and spectroscopic features of KAC/water solutions in the compositional range between 1 and 25 mol kg-1. We show the presence of a transition between the "salt-in-solvent" and "solvent-in-salt" regimes in the range of 10-15 mol kg-1. Among the explored compositions, the highest concentrations (20 and 25 mol kg-1) exhibit good room temperature conductivity values (55.6 and 31 mS cm-1, respectively) and a large electrochemical potential window (above 2.5 V).

Insight into the charge/discharge behaviour of intercalation cathode materials: relation between delivered capacity and applied rate and analysis of multi-particle intercalation mechanisms.

Exploration of the relationships and mechanisms underlying the charge/discharge behaviors of intercalation cathode materials for lithium batteries is mandatory to develop more efficient energy storage devices. Thus, herein, by combining theoretical concepts and experimental evidence, we establish/reestablish a relation/model to justify the charge-discharge behavior of many electrode materials for lithium and sodium ion batteries under a wide range of conditions. Our approach resembles a phase-field model and is correlated with the existence of diffusion regions inside the electrode particles. Regarding the determination of the relation between applied current rate and average obtained capacity (C[combining macron]), we propose that 1/C[combining macron] changes linearly versus the square root of the corresponding rate. This relation was established by previously proposed theoretical models and confirmed herein using experimental data from the literature. Accordingly, we propose an intercalation mechanism based on multi-particle (many-particle) systems, which corroborates previous experimental observations and the validity of the model. The proposed concepts can be used for better understanding the behavior of materials, predicting the C[combining macron] value versus current rate, predicting the fraction of (in)active particles, calculating the optimal cathode mass per collector area, and finally obtaining a criterion to evaluate the performance and rate-capability of cathodes, also allowing a functional comparison.

Understanding the Effect of UV-Induced Cross-Linking on the Physicochemical Properties of Highly Performing PEO/LiTFSI-Based Polymer Electrolytes.

We report a thorough, multitechnique investigation of the structure and transport properties of a UV-cross-linked polymer electrolyte based on poly(ethylene oxide), tetra(ethylene glycol)dimethyl ether (G4), and lithium bis(trifluoromethane)sulfonimide. The properties of the cross-linked polymer electrolyte are compared to those of a non-cross-linked sample of same composition. The effect of UV-induced cross-linking on the physico/chemical characteristics is evaluated by X-ray diffraction, differential scanning calorimetry, shear rheology, 1H and 7Li magic angle spinning nuclear magnetic resonance (NMR) spectroscopy, 19F and 7Li pulsed field gradient stimulated echo NMR analyses, electrochemical impedance spectroscopy, and Fourier transform Raman spectroscopy. Comprehensive analysis confirms that UV-induced cross-linking is an effective technique to suppress the crystallinity of the polymer matrix and reduce ion aggregation, yielding improved Li+ transport number (>0.5) and ionic conductivity (>0.1 mS cm?1) at ambient temperature, by tailoring the structural/morphological characteristics of the polymer matrix. Finally, the polymer electrolyte allows reversible operation with stable profile for hundreds of cycles upon galvanostatic test at ambient temperature of LiFePO4-based lithium-metal cells, which deliver full capacity at 0.05 or 0.1C current rate and keep high rate capabilities up to 1C. This enforces the role of UV-induced cross-linking in achieving excellent electrochemical characteristics, exploiting a practical, easy up-scalable process.

NASICON-type polymer-in-ceramic composite electrolytes for lithium batteries.

Hybrid polymer-ceramic electrolytes with high ceramic loading are currently investigated as a promising solution to achieve high safety and optimal mechanical properties in all-solid-state rechargeable batteries. In this study composite poly(ethylene oxide)/Li1.3Al0.3Ti1.7(PO4)3 (PEO/LATP) electrolytes, with and without lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as the Li+ salt, were investigated through a combination of physicochemical and electrochemical techniques, including X-ray diffraction, scanning electron microscopy, thermal analysis, solid-state MAS-NMR and impedance spectroscopy. We were able to shed light on the interactions between the ceramic and the polymer phases, and on the mechanisms for Li+ transport. Membranes containing 70 wt% of LATP and 30 wt% of P(EO)15LiTFSI exhibit conductivity values of 4 × 10-5 Ω-1 cm-1 at 25 °C and in excess of 10-4 Ω-1 cm-1 at 45 °C. These promising results, obtained on a quasi-ceramic electrolyte through room temperature processing, suggest that further improvements in the transport properties of "polymer-in-ceramic" systems may be sought by increasing the amorphous polymer content, and by carefully investigating the role of the ceramic particles' composition, dimensions and dispersion on the transport properties of the hybrid system.

Multicomponent crystals of gliclazide and tromethamine: preparation, physico-chemical, and pharmaceutical characterization.

OBJECTIVE: To improve the pharmaceutical behavior of the oral antidiabetic agent gliclazide through the synthesis of multicomponent crystals with tromethamine. METHODS: Multicomponent crystals were prepared by solvent evaporation method, kneading, and combining mechanical and thermal activation. DSC, FT-IR spectroscopy, X-ray diffraction, SEM-EDS, and SSNMR were used to investigate their formation. Measurements of solubility and dissolution rate were carried out for the pharmaceutical characterization. RESULTS: The formation of multicomponent crystals of gliclazide and tromethamine was confirmed by all the techniques. In particular, FT-IR and NMR measurements revealed that the interaction between drug and coformer leads to significant changes of the hydrogen bond scheme, and that almost all the functional groups of the two molecules are involved. The dissolution profile of the new phase is significantly better than that of both pure gliclazide and of the reference commercial product Diabrezide®. CONCLUSIONS: The new system shows an improved pharmaceutical behavior and could be formulated in a dosage form to obtain a rapid and complete release of the drug available for absorption.

Covalent and Ionic Functionalization of HLN Layered Perovskite by Sonochemical Methods.

We describe the functionalization of the layered perovskite HLaNb2O7 with n-propanol, n-decanol, 3-mercaptopropyl-trimethoxysilane, imidazole, n-decylamine, and histamine. The use of sonication is found to significantly improve the reaction yield and to reduce the reaction time, compared to conventional thermal treatment under reflux. The obtained intercalates are thoroughly characterized through the use of several complementary experimental techniques (scanning electron microscopy, IR spectroscopy, X-ray diffraction, thermogravimetric analysis, magic-angle spinning NMR), clarifying their structure and chemical bonding. The implications for the design of inorganic-organic composite materials are discussed.

Solid-state NMR characterization of the structure and thermal stability of hybrid organic-inorganic compounds based on a HLaNb2O7 Dion-Jacobson layered perovskite.

Dion-Jacobson phases, like MLaNb2O7, are an interesting class of ion-exchangeable layered perovskites possessing electronic and photocatalytic properties. Their protonated and organo-modified homologues, in particular, have already been indicated as promising catalysts. However, the structural analysis of these highly tailorable materials is still incomplete, and both the intercalation process and thermal stability of the included organic moieties are far from being completely understood. In this study, we present a thorough solid-state NMR characterization of HLaNb2O7·xH2O intercalated with different amounts of octylamine, or with decylamine. Samples were analyzed as prepared, and after thermal treatment at different temperatures up to 220 °C. The substitution of pristine proton ions was followed via(1)H MAS NMR spectroscopy, whereas the alkyl chains were monitored through (13)C((1)H) CP MAS experiments. The interactions in the interlayer space were explored using (13)C((1)H) 2D heteronuclear correlation experiments. We demonstrate that some of the protons are involved in the functionalization reaction, and some of them are in close proximity to the alkyl ammonium chains. Heating of the hybrid materials leads first to a rearrangement of the alkyl chains and then to their degradation. The spatial arrangement of the chains, their interactions and the thermal behavior of the materials depend on the extent of the functionalization, and on the nature of the intercalated alkyl ammonium ions.

Biocompatibility of functionalized boron phosphate (BPO4) nanoparticles for boron neutron capture therapy (BNCT) application.

Boron neutron capture therapy (BNCT) is a radiotherapy treatment based on the accumulation in the tumor of a (10)B-containing drug and subsequent irradiation with low energy neutrons, which bring about the decay of (10)B to (7)Li and an α particle, causing the death of the neoplastic cell. The effectiveness of BNCT is limited by the low delivery and accumulation of the used boron-containing compounds. Here we report the development and the characterization of BPO4 nanoparticles (NPs) as a novel possible alternative drug for BNCT. An extensive analysis of BPO4 NP biocompatibility was performed using both mature blood cells (erythrocytes, neutrophils and platelets) and a model of hematopoietic progenitor cells. A time- and concentration-dependent cytotoxicity study was performed on neoplastic coloncarcinoma and osteosarcoma cell lines. BPO4 functionalization with folic acid, introduced to improve the uptake by tumor cells, appeared to effectively limit the unwanted effects of NPs on the analyzed blood components. FROM THE CLINICAL EDITOR: Boron neutron capture therapy (BNCT) is a radiotherapy treatment modality based on the accumulation of a (10)B-containing drug and subsequent irradiation with low energy neutrons, inducing the decay of (10)B to (7)Li and an α particle, causing neoplastic cell death. This team of authors reports on a folic acid functionalized BPO4 nanoparticle with improved characteristics compared with conventional BNCT approaches, as demonstrated in tumor cell lines, and hopefully to be followed by translational human studies.

Inherent Behavior of Electrode Materials of Lithium-Ion Batteries.

For independency from the fossil fuels and to save environment, we need to move toward the green energies, which requires better energy storage devices, especially for usage in electric vehicles. Li-ion and beyond-lithium insertion batteries are promising to this aim. However, they suffer from some inherent limitations which must be understood to allow their development and pave the way to find suitable energy storage alternatives. It is found that each positive or negative electrode material (cathode or anode) of the intercalation batteries has its own behavioral (charge-discharge) properties. The modification of preparation parameters (composition, loading density, porosity, particle size, etc.) may improve some aspects of the electrode performance, but cannot change the intrinsic property of the electrode itself. Accordingly, these properties are called as the "inherent behavior characteristics" of the active material. It is concluded that the behavior of a specific electrode substance, even following different preparation routes, depends only on diffusion mechanisms. This work shows that the inherent electrode properties can be visualized by representation of current density vs. capacity.

An ab initio investigation of Li2M(0.5)N(0.5)SiO4 (M, N = Mn, Fe, Co Ni) as Li-ion battery cathode materials.

Li2MSiO4 (M = Fe, Mn, etc.) are promising cathode materials for Li-ion batteries. One appealing strategy for improving their cathode properties is to develop mixed transition metal compounds. Density Functional Theory calculations were performed to evaluate the structural, magnetic and electrochemical properties of Li2M0.5N0.5SiO4 compounds. Our theoretical study allows us to individuate the most promising candidates for practical applications in lithium batteries.

Structure-Property Correlations in Aqueous Binary Na+/K+-CH3COO- Highly Concentrated Electrolytes.

Highly concentrated aqueous binary solutions of acetate salts are promising systems for different electrochemical applications, for example, energy storage devices. The very high solubility of CH3COOK allows us to obtain water-in-salt electrolyte concentrations, thus reducing ion activity and extending the cathodic stability of an aqueous electrolyte. At the same time, the presence of Li+ or Na+ makes these solutions compatible with intercalation materials for the development of rechargeable alkaline-ion batteries. Although there is a growing interest in these systems, a fundamental understanding of their physicochemical properties is still lacking. Here, we report and discuss the physicochemical and electrochemical properties of a series of solutions based on 20 mol kg-1 CH3COOK with different concentrations of CH3COONa. The most concentrated solution, 20 mol kg-1 CH3COOK + 7 mol kg-1 CH3COONa, gives the best compromise between transport properties and electrochemical stability, displaying a conductivity of 21.2 mS cm-1 at 25 °C and a stability window of up to 3 V in "ideal" conditions, i.e., using a small surface area and highly electrocatalytic electrode in a flooded cell. Careful Raman spectroscopy analyses help to address the interaction network, the phase evolution with temperature, and the crystallization kinetics.

Nanoparticles induce platelet activation in vitro through stimulation of canonical signalling pathways.

Nanomaterials are attracting growing interest for their potential use in several applications as nanomedicine; therefore, the analysis of their potential toxic effects on various cellular models, including circulating blood cells, is mandatory. This study aimed to investigate the effect of three unrelated nanomaterials, namely nanoscale silica, multiwalled carbon nanotubes, and carbon black, on platelet activation and aggregation. We found that these nanomaterials stimulate some of the typical biochemical pathways involved in canonical platelet activation, such as the stimulation of phospholipase C and Rap1b, resulting in the integrin α(IIb)ß3-mediated platelet aggregation, through a mechanism largely dependent on the release of the extracellular second messengers ADP and thromboxane A2. Importantly, we found that doses of nanoparticles unable to trigger appreciable responses can synergize with subthreshold amounts of physiological agonists to mediate platelet aggregation, indicating that even small amounts of nanomaterials in the bloodstream might contribute to the development of thrombosis. FROM THE CLINICAL EDITOR: In this study, nanosized particles of three virtually unrelated materials (silica, multi-walled carbon nanotubes and carbon black) were investigated regarding their effects on platelet activation and aggregation. All were found to stimulate some of the typical biochemical pathways involved in canonical platelet activation, and were found to have synergistic effects with physiologic platelet activator agonists.

Electrolytes for solid-state lithium rechargeable batteries: recent advances and perspectives.

This critical review presents an overview of the various classes of Li(+) conductors for use as electrolytes in lithium polymer batteries and all-solid state microbatteries. Initially, we recall the main models for ion transport and the structure-transport relationships at the basis of the observed conductivity behaviours. Emphasis is then placed on the physico-chemical and functional parameters relevant for optimal electrolytes preparation, as well as on the techniques of choice for their evaluation. Finally, the state of the art of polymer and ceramic electrolytes is reported, and the most interesting strategies for the future developments are described (121 references).

What is Next in Anion-Exchange Membrane Water Electrolyzers? Bottlenecks, Benefits, and Future.

As highlighted by the recent roadmaps from the European Union and the United States, water electrolysis is the most valuable high-intensity technology for producing green hydrogen. Currently, two commercial low-temperature water electrolyzer technologies exist: alkaline water electrolyzer (A-WE) and proton-exchange membrane water electrolyzer (PEM-WE). However, both have major drawbacks. A-WE shows low productivity and efficiency, while PEM-WE uses a significant amount of critical raw materials. Lately, the use of anion-exchange membrane water electrolyzers (AEM-WE) has been proposed to overcome the limitations of the current commercial systems. AEM-WE could become the cornerstone to achieve an intense, safe, and resilient green hydrogen production to fulfill the hydrogen targets to achieve the 2050 decarbonization goals. Here, the status of AEM-WE development is discussed, with a focus on the most critical aspects for research and highlighting the potential routes for overcoming the remaining issues. The Review closes with the future perspective on the AEM-WE research indicating the targets to be achieved.

Cathode Active Material Recycling from Spent Lithium Batteries: A Green (Circular) Approach Based on Deep Eutectic Solvents.

The transition to a circular economy vision must handle the increasing request of metals required to satisfy the battery industry; this can be obtained by recycling and feeding back secondary raw materials recovered through proper waste management. Here, a novel and green proof-of-concept was developed, based on deep eutectic solvents (DESs) to fully and easily recover valuable metals from various cathode active materials, including LiMn2 O4 , LiNi0.5 Mn1.5 O4 , and LiNi0.8 Co0.2 O2 . DES composed of choline chloride and lactic acid could leach Li, Mn, Co, and Ni, achieving efficiency of 100 % under much milder conditions with respect to the previous literature. For the first time, to our best knowledge, a two-step approach was reported in the case of LiNi0.8 Co0.2 O2 for selective recovery of Li, Co, and Ni with high yield and purity. Furthermore, other cathode components, namely aluminum current collector and binder, were found to be not dissolved by the proposed DES, thus making a simple separation from the active material possible. Finally, this strategy was designed to easily regenerate and reuse the leaching solvents for more than one extraction, thus further boosting process sustainability.

The Electrical Response of Real Dielectrics: Using the Voltage Ramp Method as a Straightforward Diagnostic Tool for Polymeric Composites.

An experimental method exploiting the capacitive response of most materials is here revised. The procedure called the "Voltage Ramp Method" (VRM) is based on applying proper voltage ramp cycles over time and measuring electrical current intensity flowing through the material sample. In the case of an ideal capacitor, a current plateau should be easily measured, and the capacitance value precisely determined. However, most media, e.g., semiconductors and insulating polymers, show dielectric absorption and hence electric leakage effects. Therefore, the VRM method allows simultaneous determination of their equivalent capacitance and resistance. Some case studies are discussed as concerning the application of VRM to both standard and actual media. A figure of merit of the method is the percentage difference between 2.5% and 1.5% with respect to the nominal values of a commercial capacitor and resistor, respectively. The simulation modeling of the material electrical response is compared to the experimental data also on polymer nanocomposites suitable for energy harvesting.

In vitro calcified matrix deposition by human osteoblasts onto a zinc-containing bioactive glass.

Bioactive glasses synthesized by the sol-gel technique possess many of the qualities associated with an ideal scaffold material for a bone graft substitute. In view of the potential clinical applications, we performed a detailed in vitro study of the biological reactivity of synthesized 58S bioactive glass containing-zinc, in terms of osteoblast morphology, proliferation, and deposition of a mineralized extracellular matrix (ECM). Human Sarcoma Osteoblast (SAOS-2) cells were used to i) assess cytotoxicity by lactate dehydrogenase (LDH) release and ii) evaluate the deposition of a calcified extracellular matrix by ELISA assay and quantitative RT-PCR (qRT-PCR). In comparison with pure silica and 58S, the 58S-Zn0.4 bioglass showed a significant increase in cellular proliferation and deposition of ECM components such as decorin, fibronectin, osteocalcin, osteonectin, osteopontin, type-I and -III collagens. Calcium deposition was significantly higher than on pure silica and 58S samples. Also Alkaline phosphatase (ALP) activity and its protein content was higher with respect to pure silica and 58S. qRT-PCR analysis revealed the up-regulation of type-I collagen, bone sialoprotein and osteopontin genes. All together these results demonstrate the cytocompatibility of 58S-Zn0.4 bioglass and its capability to promote osteoblast differentiation.