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Dendrite formation, which could cause a battery short circuit, occurs in batteries that contain lithium metal anodes. In order to suppress dendrite growth, the use of electrolytes with a high shear modulus is suggested as an ionic conductive separator in batteries. One promising candidate for this application is Li7La3Zr2O12 (LLZO) because it has excellent mechanical properties and chemical stability. In this work, in situ scanning electron microscopy (SEM) technique was employed to monitor the interface behavior between lithium metal and LLZO electrolyte during cycling with pressure. Using the obtained SEM images, videos were created that show the inhomogeneous dissolution and deposition of lithium, which induce dendrite growth. The energy dispersive spectroscopy analyses of dendrites indicate the presence of Li, C, and O elements. Moreover, the cross-section mapping comparison of the LLZO shows the inhomogeneous distribution of La, Zr, and C after cycling that was caused by lithium loss near the Li electrode and possible side reactions. This work demonstrates the morphological and chemical evolution that occurs during cycling in a symmetrical Li–Li cell that contains LLZO. Although the superior mechanical properties of LLZO make it an excellent electrolyte candidate for batteries, the further improvement of the electrochemical stabilization of the garnet–lithium metal interface is suggested.

The great growth of the photovoltaic panels industry generates an important amount of slurry during the sawing step, two techniques are used: metallic wire sawing and diamond wire sawing. The metallic wire sawing slurry can mainly contain particles of pure silicon up to 40% Wt, particles of silicon carbide (SiC) which are used as an abrasive element during sawing, metallic impurities based on iron (Fe) which come from the wire, polyethylene glycol (PEG) which is used as a lubricant. However, the sawing stage determines the cost of producing photovoltaic cells, so its recovery has become a necessity. For this purpose, we are interested to study the chemical behavior of the input elements involved in the composition of the slurry. For that, the pH of the slurry was measured for 7 days during its storage. Then, it was washed with acetone to dissolve the polyethylene glycol and separate the liquid phase from the solid one. Solid phase was dried at 70 °C to obtain a slurry powder. This powder has been characterized by ATR-FTIR spectroscopy, Raman spectroscopy and the X-ray diffractometer. The liquid phase has been characterized by ATR-FTIR, Raman and TGA analysis. The results confirm the chemical instability of the slurry and the appearance of nanoparticles that have been identified.

In the interest of reducing the cost of photovoltaic production while preserving the environment, a sawing rejection treatment was carried out by recovering the metals with an efficiency estimated to be 96%. To achieve this outcome, first, the sawing rejection was washed with acetone to dissolve the polyethylene glycol. It was then dried in an oven at 70 °C to obtain a slurry powder. This later, powder has undergone a dry magnetic separation under different electric current intensity to recover metals. The metal-containing phase has been characterized by the X-ray diffractometer and the scanning electron microscope. Finally, a simulation on the recovery of metal fragments in the slurry generated during the manufacture of photovoltaic briquettes.

We present the first results of in situ scanning electron microscopy (SEM) of an all-solid Li battery with a nickel-manganese-cobalt-oxide (NMC-622) cathode at 50 °C and an operating voltage of 2.7-4.3 V. Experiments were conducted under a constant current at several C rates (

International audience; The growth process and post-deposition treatment have strong effects on the structure of ZnO thin films, which can also significantly affect their electrical and piezoelectric properties. In this report, the effect of high temperature annealing under oxygen atmosphere on ZnO stacked thin films grown on silicon by pulsed-liquid injection metal-organic chemical vapor deposition is investigated in detail. By varying the annealing temperature from 600 to 1000 °C, the structural analysis reveals the occurrence of c-axis oriented grain coarsening and growth processes associated with the improvement of crystallinity and removal of carbon impurities. The electrical resistivity also strongly varies with thermal annealing. Those variations are accompanied by an enhancement of the piezoelectric amplitude measured by piezo-response force microscopy (PFM). Interestingly, the PFM measurements reveal the predominant development of O-and Zn-polar domains at low and high temperature annealing, respectively, originating from the anisotropic grain boundary velocity. The present findings show that the high temperature annealing under oxygen atmosphere in ZnO thin films can enhance not only its piezo-amplitude but also its Zn-polarity uniformity, which unambiguously leads to the improvement of its piezoelectric performance.

In this work, a non-toxic protonated kaolin clay exchanged with protons, was successfully applied as a solid acid catalyst for the polymerization of tetrahydrofuran (poly(THF)) at room temperature in the presence of acetic anhydride. Prior to using the kaolin as a catalyst, it was treated with HCl (0.1 M) and characterized using various analytical techniques. The amounts of catalyst and reaction time on the conversion of THF were investigated. Characterizations of nuclear magnetic Resonance of proton (1H-NMR), Fourier Transform Infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), Optical Microscopy (OM), and Differential Scanning Calorimetry (DSC) techniques were used to examine the resulting polymer. X-ray characterization and DSC data indicated that the obtained poly(THF) is a highly crystalline substance. The results showed that protonated kaolin (kaolin–H+) has a high catalytic activity for the polymerization of THF with a conversion rate of 50.02% after 20 hours. Copyright © 2019 BCREC Group. All rights reserved.

In this work, we deposited a nanometric layer of platinum (40 nm thick) on a standard propylene/polypropylene Celgard separator 3501 by plasma sputtering, and studied the effect of this thin layer when in contact with a lithium metal anode in a Li-S battery. The platinum-coated Celgard slowed down the shuttle effect at low current density (C/10) compared to standard Celgard and led to an increase in capacity retention at higher current density (C/2). In addition, the polarization was reduced with a platinum separator in a Li-Li symmetric cell after 500 h.

We report on the synthesis of amphiphilic polymers with a composition shift of the hydrophobic block made by emulsion polymerization that is used as a water-based binder for LiFePO4 cathodes. The integrity of the electrode is sustained by using a unique chemical procedure for cross-linking the binder. This technique yields higher adhesion of the binder on aluminium collectors comparing with the state-of-the-art binders. Amphiphilic polymers are excellent for well-dispersed inorganic particles, and consequently demonstrate satisfactory electrochemical performances.

We report on the nanopatterning of horizontal and vertical germanium-tin (Ge1−x Sn x or GeSn) nanowires by inductively coupled plasma reactive ion etching for gate-all-around field effect transistors. First, a chlorine based chemistry has been investigated and optimal conditions identified for GeSn 6% alloys. Then, plasma etching was optimized to etch high Sn content GeSn alloys (up to 15%) with a high anisotropy, smooth sidewalls and a high selectivity versus a hydrogen silsesquioxane hard mask. We have shown that, in order to obtain smooth surfaces after plasma etching, a HCl pre-treatment was mandatory to eliminate the native Sn and Ge oxides. This behavior was even more pronounced for high Sn contents. Finally, we succeeded in patterning 20 nm wide suspended beams from GeSn layers with Sn concentrations up to 15%.

ZnO thin films and nanostructures have received increasing interest in the field of piezoelectricity over the last decade, but their formation mechanisms on silicon when using pulsed-liquid injection metal–organic chemical vapor deposition (PLI-MOCVD) are still open to a large extent. Also, the effects of their morphology, dimensions, polarity, and electrical properties on their piezoelectric properties have not been completely decoupled yet. By only tuning the growth temperature from 400 to 750 °C while fixing the other growth conditions, the morphology transition of ZnO deposits on silicon from stacked thin films to nanowires through columnar thin films is shown. A detailed analysis of their formation mechanisms is further provided. The present transition is associated with strong enhancement of their crystallinity and growth texture along the c-axis together with a massive relaxation of the strain in nanowires. It is also related to a prevailed zinc polarity, for which its uniformity is strongly improved in nanowires. The nucleation of basal-plane stacking faults of I1-type in nanowires is also revealed and related to an emission line at about 3.326 eV in cathodoluminescence spectra, further exhibiting fairly low phonon coupling. Interestingly, the transition is additionally associated with a significant improvement of the piezoelectric amplitude, as determined by piezoresponse force microscopy measurements. The Zn-polar domains exhibit a larger piezoelectric amplitude than the O-polar domains, showing the importance of controlling the polarity in these deposits as a prerequisite to enhance the performances of piezoelectric devices. The present findings demonstrate the high potential in using the PLI-MOCVD system to form ZnO with different morphologies and polarity uniformity on silicon. They further reveal unambiguously the superiority of nanowires over thin films for piezoelectric devices.

The purpose of this study is to compare the effectiveness of a natural and / or modified kaolinite to adsorb chromium-containing aqueous effluents in its most toxic form (the hexavalent chromate ion (Cr (VI)). Adsorbant used in the present study is a kaolinite of hydrothermal origin. The modified kaolinite has been prepared by insertion of a cationic surfactant DTAC in interlayer space of this clay. The modification method is generally performed by the cation exchange reaction in the liquid state. The specific surface areas determined by nitrogen adsorption at 77 K for the two samples of kaolinite (natural and modified) are succinctly 48.75 and 63.72 m2/g. Scanning electron microscopy has shown that the used clay is in tubular form. The treatment of natural kaolin by the intercalation of cationic surfactant increased its specific surface of about 18 %. Therefore its power sorptif increased which was found by a comparative study of adsorption of Cr (VI) on natural kaolin and / or modified.

The interest of mixing PVC-C and EVA with different concentrations (5–10–15–20%) is to combine the useful properties to develop a product resistant to thermal aging and gamma rays up to 50 KGy. In this study, the effect of aging on mechanical properties (tensile strength, elongation at break and Young modulus) and the changes induced in the thermal analysis and morphology due to gamma radiation was investigated. The results revealed that the gamma irradiation affected considerably the PVC-C properties at 50 KGy. This degradation is due to the chain scission, which caused a reduction in the average molecular weight and cross-linking rate on the one hand, but this degradation was not observed in PVC-C/EVA/20%.

Cr, Fe and Si were added to improve the performance of olivine LiCoPO4 in cathodes for lithium-ion batteries. A substituted-LiCoPO4 in a half cell delivered a reversible capacity of 125 mAh/g at C/3 rate, with no capacity loss after over 100 cycles at 25 °C. The well-known capacity fade of LiCoPO4-based cathodes was almost completely eliminated by substituting Cr, Fe and Si.

Aqueous lithium-ion batteries are emerging as strong candidates for a great variety of energy storage applications because of their low cost, high-rate capability, and high safety. Exciting progress has been made in the search for anode materials with high capacity, low toxicity, and high conductivity; yet, most of the anode materials, because of their low equilibrium voltages, facilitate hydrogen evolution. Here, we show the application of olivine FePO4 and amorphous FePO4·2H2O as anode materials for aqueous lithium-ion batteries. Their capacities reached 163 and 82 mA h/g at a current rate of 0.2 C, respectively. The full cell with an amorphous FePO4·2H2O anode maintained 92% capacity after 500 cycles at a current rate of 0.2 C. The acidic aqueous electrolyte in the full cells prevented cathodic oxygen evolution, while the higher equilibrium voltage of FePO4 avoided hydrogen evolution as well, making them highly stable. A combination of in situ X-ray diffraction analyses and computational studies reveal...

High-performance and long-cycling rechargeable lithium-ion batteries have been in steadily increasing demand for the past decades. Nevertheless, the two dominant anodes at the moment, graphite and L4T5O12, suffer from a safety issue of lithium plating (operating voltage at ∼ 0.1 V vs. Li+/Li) and low capacity (175 mAh/g), respectively. Here, we report LiNi1/3Co1/3Mn1/3O2 as an alternative anode material which has a working voltage of ∼1.1 V and a capacity as high as 330 mAh/g at the current rate of C/15. Symmetric cells with both electrodes containing LiNi1/3Co1/3Mn1/3O2 can deliver average discharge voltage of 2.2 V. In-situ XRD, HRTEM and first principles calculations indicate that the reaction mechanism of a LiNi1/3Co1/3Mn1/3O2 anode is comprised mainly of conversion. Both the fundamental understanding and practical demonstrations suggest that LiNi1/3Co1/3Mn1/3O2 is a promising negative electrode material for lithium-ion batteries.

Recently many observations related to the catalytic effects of layered metal disulfide versus polysulfide electrochemistry were documented. In this work, we investigated the reactivity of layered WS2 in a Li-S battery and observed a chemical reaction involving the removal of W ions by polysulfides. The presence of metallic tungsten nanoparticles in the sulfur cathode is the result of W ion oxidation reaction and subsequent recrystallization during cycling. In situ Raman spectroscopy and ex situ transmission electron microscopy were used in order to clarify the reaction mechanism.

Lithium–sulfur batteries are of great interest owing to their high theoretical capacity of 1675 mA h g−1 and low cost. Their discharge mechanism is complicated and it is still a controversial issue. In the present work, in situ Raman spectroscopy is employed to investigate the poly-sulfide species in the sulfur cathode and in the electrolyte during the cycling of Li–S batteries. The aim is to understand the discharge mechanism and the influence of the electrolyte on the dissolution of sulfur and poly-sulfides. S8n− is identified as the main species in the high voltage plateau of discharge together with cycloocta S8, in the cell using 0.5 mol L−1 LiTFSI–PY13–FSI as the electrolyte. S42−, S22− and S2− are detected soon after the low voltage plateau is reached. A discharge mechanism in the PY13–FSI is proposed based on the identified species which provides important information for improving and designing cathodes. Electrolytes of 0.5 mol L−1 LiTFSI–PY13–FSI and 1 mol L−1 LiTFSI–DOL–DME are used in studying the dissolution of sulfur and poly-sulfides. The results demonstrate that the same poly-sulfide species are present in the two electrolytes. However, the rates of poly-sulfide formation and diffusion to the anode are slow in the ionic liquid compared to those in the ether-based electrolyte due to different ionic mobilities of various species in the two electrolytes. These differences are evidenced by the observation of poly-sulfide species in the DOL–DME from the very beginning of cell assembly even before starting the discharge whereas their appearances, in the ionic liquid, are delayed and only found at the end of the high voltage plateau. Notably, the soluble elemental sulfur is clearly observed in the ionic liquid electrolyte during the first discharge in the high voltage region, which is very different from the DOL–DME system where the elemental sulfur is quickly reduced to poly-sulfides due to self-discharge reactions. In addition, the elemental sulfur is also detected near the lithium anode in DOL–DME at the end of charge, for the first time to our knowledge, which suggests that the degradation of lithium metal is caused by the multiple reactions of the lithium metal surface with soluble poly-sulfides and/or elemental sulfur.

In this study, flexible plastic electrochromic devices (ECDs) based on viologen-modified TiO2 nanostructured films thermally treated at only 120 °C are reported. Even if a sintering process at typically above 450 °C was avoided, the resulting mesoporous TiO2 films were highly transparent on both TCO-coated glass and plastic substrates while presenting adequate conductivity and high active surface area suitable for anchoring electro-chromophores. The synthesis of a viologen specifically designed to provide colorless-to-blue switching while being more compatible with plastic substrates than the traditional ethyl viologen is reported as well. The effect of the TiO2 layer thickness and pore characteristics as well as the grafting time on the device performance were also investigated. Transparent ECDs based on these viologen-modified TiO2 films have been assembled on flexible plastic substrate (ITO/PET) offering transmittance changes (ΔT) above 60% and switching speeds of 6–8 s. The change in transmittance is further enhanced up to 71% in dual ECDs using PB on ITO/PET as the counter electrode and viologen-modified TiO2 films on FTO/glass. Finally, operational large-area all-solid devices (40 cm×30 cm) are presented, demonstrating the suitability of the present technology for the production of large-area plastic ECDs.

Rechargeable lithium batteries accelerated the wireless revolution over the last two decades, and they are now a mature technology for transportation applications in electric vehicles (EV). However, numerous studies have concluded that the proven lithium reserves can hardly absorb the growth in demand. Therefore, sustainable sodium batteries are being considered to overcome the lithium resource shortages that may arise from large-scale application in EVs and stationary energy storage. It is difficult to find a suitable host material for reversible Na-ion storage due to the size of the Na+ ion (0.102 nm) compared to the Li+ ion (0.076 nm). Here we report a low cost and simple sodium technology that is based on a metal-free cathode material. Sodium metal was used as the anode with a conducting polymer cathode and electrochemically tested in a liquid electrolyte. With this technology, a host material for Na intercalation is not required, and because a polymer conductor is used, the size of the Na ion is not an issue.

We report a new sol-gel approach of synthesis of LiFePO 4 (LFP) thin film and its application as cathode materials for transparent Li-ion battery in half-cell configuration. LFP thin films were obtained from an alcoholic colloidal suspension of iron acetylacetonate (Fe(AcAc) 3 ) and aqueous lithium dihydrogen phosphate (LiH 2 PO 4 ) deposited on fluorine tin oxide (FTO) glass substrate, followed by heating at 450 °C under nitrogen gas for 1 h. X-ray diffraction (XRD) confirmed that the LFP films have an orthorhombic crystal system with space group Pnma (62). Scanning electron microscopy (SEM) shows spherical LFP nanoparticles aggregates homogenously deposited all over the surface of FTO substrate containing 3-D open pores. The electrochemical behaviors of thin film vs Li/Li + cell were investigated by cyclic voltammetry and galvanostatic charge-discharge measurements. The cycle life was evaluated by running 1000 cycles of charge-discharge at a current density of 20 μA/cm 2 . The transmission spectra reveal 85–90% of transparency versus FTO as reference, which makes it a potential candidate as a complementary electrode in electrochromic devices (ECDs).

Sulfide-based ionic conductors are one of most attractive solid electrolyte candidates for all-solid-state batteries. In this review, recent progress of sulfide-based solid electrolytes is described from point of view of structure. In particular, lithium thio-phosphates such as Li7P3S11, Li10GeP2S12 and Li11Si2PS12 etc. exhibit extremely high ionic conductivity of over 10−2 S cm−1 at room temperature, even higher than those of commercial organic carbonate electrolytes. The relationship between structure and unprecedented high ionic conductivity is delineated; some potential drawbacks of these electrolytes are also outlined.

Sodium-ion batteries offer a promising alternative to lithium-ion batteries due to their low cost, environmental friendliness, high abundance of sodium, and established electrochemical process. However, problems, such as low capacity, low storage voltage and capacity fade of electrode materials, must be resolved for the applications of sodium ion batteries. Many Ti-containing compounds were reported as cathode and anode materials, but very few studies focus on the role of Ti in electrodes used in sodium-ion batteries. This paper systemically reviews the roles of Ti in electrodes of sodium ion batteries. The Ti4+/Ti3+ redox couple is a good choice for anodes due to its low potential and it exhibits different storage voltages in different structures. Although Ti4+ does not participate in charge transfer in cathodes, it can indirectly enhance the capacity, cycling life and rate performance via structure change, cation order-disorder transition, and its interaction with the crystal lattice structure. This review will provide a new insight in designing and understanding novel high-performance electrodes.

This work focuses on the stability of hybrid electrochromic displays that use only one electrochromic film, an industrial solid polymer electrolyte and a metallic counter electrode. The lifetime of these devices exceeds 200,000 cycles in tests with three different voltage ranges. Traces of metal deposits were found during cycling, which indicates that the metallic counter electrode combines the functions of current collector and counter electrode.

Crystalline lithium disulfide (Li2S2) is identified, for the first time, as a transient species in the lithium-sulfur cell, by using an operando X-ray diffraction (XRD) technique. The observed XRD pattern precisely matches with the predicted pattern based on the density function theory. The formation of Li2S2 crystals is repetitively found in the highly concentrated (7 M Li+) electrolyte at high voltage region (>2 V) near the end of the first charge cycle and before the end of the second discharge cycle. These conditions indicate that crystalline Li2S2 exists in the non-equilibrium regime. The formation of crystalline Li2S2 under only the specified conditions suggests that it is not formed as an intermediate discharge product, contrary to what is generally believed, but as a transient species by the disproportionation reaction from higher order polysulfides which is facilitated by the “solvent-in-salt” conditions.

The environmental and economic impacts linked with solar systems are largely based on discharges of slurry generated during the various stages of sawing and cutting ingots. These discharges into the environment are subject to the general regulations on hazardous and special industrial waste disposal. Therefore, they should not be abandoned or burned in open air. The cutting of Silicon ingots leads to the production of Silicon wafers additional costs, losing more than 30% of Silicon material. Abrasive grains (Silicon Carbide) trapped between the wire and the block of Silicon need to be removed by various mechanisms to be later evacuated by slurry fragments. In the interest of decreasing operational costs during polycrystalline ingot slicing at Semiconductors Research Center, and, avoid environmental problems; it is necessary to recover the solar grade Silicon from the Silicon sawing waste. For this reason, the removal of metal fragments has become a preliminary requirement to regenerate the slurry; in addition, the solid phase needs to be separated from the liquid phase after the dissolution PEG with the solvent. In the present study, magnetic separation and centrifugation methods were adopted for metals removal, followed by the analysis of some operating parameters such as: washing time, pH, and initial concentration of Silicon. Finally, analytical, morphological and basic methods were performed in order to evaluate the efficiency of the process undertaken.

Lithium/solid polymer electrolyte (SPE)/sulfur cells were studied in operando by two techniques: Scanning Electron Microscope (SEM) and ultraviolet–visible absorption spectroscopy (UV–vis). During the operation of the cell, extensive polysulfide dissolution in the solid polymer electrolyte (cross-linked polyethylene oxide) leads to the formation of a catholyte. A clear micrograph of the thick passivation layer on the sulfur-rich anode and the decreased SPE thickness by cycling confirmed the failure mechanism; the capacity decays by reducing the amount of active material, and by contributing to a charge inhibiting mechanism called polysulfide shuttle. The formation of elemental sulfur is clearly visible in real time during the charge process beyond 2.3 V. The non-destructive in operando UV–vis study also shows the presence of characteristic absorption peaks evolving with cycling, demonstrating the accumulation of various polysulfide species, and the predominant formation of S42− and of S62− during discharge and charge, respectively. This finding implies that the charge and discharge reactions are not completely reversible and proceed along different pathways.

Transparent Li4Ti5O12 and LiMn2O4 thin films were prepared on transparent conducting oxide substrates via sol–gel dip coating technique. The resulting films were highly uniform and transparent after annealing at 600 °C and 400 °C for Li4Ti5O12 and LiMn2O4, respectively. Different film thicknesses ranging from 50 nm to about 800 nm were attained and the films were characterized by scanning electron microscopy (SEM) for surface morphology and X-ray diffraction (XRD) for evaluating the crystallization of the active materials. Ellipsometric porosimetry was used to measure the porosity of the anode material. Furthermore, electrochemical techniques such as cyclovoltametry and galvanostatic charging/discharging confirm the successful synthesis of electrochemically active LiMn2O4 and Li4Ti5O12 films. Single-layer electrodes show stable capacities at discharge rates up to 100C indicating the high rate capability and therefore and therefore are classified as materials for power. Furthermore, the electrochromic effects were observed for both thin-film systems and evaluated in preliminary tests.

Sodium-ion batteries (SIBs) are in the spotlight because of their potential use in large-scale energy storage devices due to the abundance and low cost of sodium-based materials. There are many SIB cathode materials under investigation but only a few candidate materials such as carbon, oxides and alloys were proposed as anodes. Among these anode materials, hard carbon shows promising performances with low operating potential and relatively high specific capacity. Unfortunately, its low initial coulombic efficiency and high cost limit its commercial applications. In this study, low-cost maple tree-biomass-derived hard carbon is tested as the anode for sodium-ion batteries. The capacity of hard carbon prepared at 1400 &deg, C (HC-1400) reaches 337 mAh/g at 0.1 C. The initial coulombic efficiency is up to 88.03% in Sodium trifluoromethanesulfonimide (NaTFSI)/Ethylene carbonate (EC): Diethyl carbonate (DEC) electrolyte. The capacity was maintained at 92.3% after 100 cycles at 0.5 C rates. The in situ X-ray diffraction (XRD) analysis showed that no peak shift occurred during charge/discharge, supporting a finding of no sodium ion intercalates in the nano-graphite layer. Its low cost, high capacity and high coulombic efficiency indicate that hard carbon is a promising anode material for sodium-ion batteries.

It may be argued that the remarkable properties of the high-temperature superconducting cuprates such as the insulator–metal transition (IMT) and the metal–superconductor transition (MST) originate from competition and interplay between the interlayer ionic interaction and the intralayer covalent bonds in these materials. It is proposed here that the microscopic order parameter is the local field estimated from the ionic polarization at the sub-unit cell level, and it is demonstrated that it shows a strong temperature as well as chemical doping dependence. The out-of-plane ionicity induces an interlayer electron transfer that reduces the ionicity of the layers and leads to IMT, while the in-plane covalency induces in-plane intersite hole transfer that increases the out-of-plane ionicity. It is suggested that this competition leads to a local field catastrophe at a critical temperature T c that drives the compound to MST. The asymmetry of the free charge carrier density breaks locally the mirror reflection symmetry of the order parameter, leading to a pairing between the real current and the polarization current.

International audience; A vertical MOS architecture implemented on Si nanowire (NW) array with a scaled Gate-All-Around (14 nm) and symmetrical diffusive S/D contacts is presented with noteworthy demonstrations in both processing (layer engineering at nanoscale), and in electrical properties (high electrostatic control, low defect level, multi-Vt platform). Furthermore, the versatility and reliability of this technology is evidenced with a CMOS inverter, providing bright perspectives for ultimate scaling.

Recently, intensive efforts are dedicated to convert and store the solar energy in a single device. Herein, dye-synthesized solar cell technology is combined with lithium-ion materials to investigate light-assisted battery charging. In particular we report the direct photo-oxidation of lithium iron phosphate nanocrystals in the presence of a dye as a hybrid photo-cathode in a two-electrode system, with lithium metal as anode and lithium hexafluorophosphate in carbonate-based electrolyte; a configuration corresponding to lithium ion battery charging. Dye-sensitization generates electron–hole pairs with the holes aiding the delithiation of lithium iron phosphate at the cathode and electrons utilized in the formation of a solid electrolyte interface at the anode via oxygen reduction. Lithium iron phosphate acts effectively as a reversible redox agent for the regeneration of the dye. Our findings provide possibilities in advancing the design principles for photo-rechargeable lithium ion batteries., Photo-rechargable energy storage cells can provide plug-free power for various applications. Here the authors integrate a photo-absorbing dye complex with LiFePO4 nanocrystals as a lithium-ion battery cathode in a two-electrode system demonstrating its photo-charging and galvanostatic discharging.

Well-known since the 18th century and widely used in painting and later in photography, hexacyanoferrate, or “Prussian blue”, is currently getting its “second life” as a promising material in several of the most advanced fields of the present technological sectors. This is mostly due to the rapid development of the energy storage market, which requires advanced, reliable, but also cost-effective materials for large-scale applications in load-levelling of renewable energy power sources. Non-Li technologies are considered as one of the most fertile R&D directions in this field, and Prussian blue demonstrates extremely promising characteristics for this kind of application. The unique features of this material are due to peculiarities of its atomic structure and ionic and electronic properties. In this article we review and discuss current research efforts in this field employing different hexacyanoferrate-based compounds as potential electrochemical storage and electrochromic devices. After a brief review of its history, we analyze the peculiarities of the atomic structure of these types of systems. We further summarize and analyze the most important and interesting experimental electrochemical data in this field, linking the particular atomic structure of the studied compounds with their observed electrochemical behaviour. This provides us with a snapshot of the current experimental state in this field and allows us to make certain predictions for its future development.

A non-aqueous zinc–polyaniline secondary battery was fabricated with polyaniline Emeraldine base as cathode and zinc metal as anode in an electrolyte consisting of 0.3 M zinc-bis(trifluoromethyl-sulfonyl)imide Zn(TFSI) 2 dissolved in propylene carbonate. We observed that the formation of the battery required a prerequisite condition to stabilize the interfaces in order to maintain a stable capacity. The battery suffered from Zn dissolution which induces a competition between concurrent Zn dissolution and plating when the battery is in charge mode, and thus inefficient cycles are obtained. The capacity and coulombic efficiency of the battery depends on the charge–discharge rates. We propose cycling protocols at different rates to determine the steady-state rates of competing reactions. When the cell is cycled at ≥1 C rate, the coulombic efficiency improves. The maximum capacity and energy densities of the battery are 148 mAhg −1 and 127 mWhg −1 , respectively for discharge at C/2. The battery was successively charged/discharged at constant current densities (1C rate), and high cycling stability was obtained for more than 1700 cycles at 99.8% efficiency. Zinc dissolution and self discharge of the battery were investigated after 24 h of standby. The investigation showed that the battery experiences a severe self-discharge of 48% per day.

In this work, we analyzed the thermal stability of polycarbonate: lithium trifluoromethane sulphonylimide (LiTFSI) systems. Polyethylene carbonate (PEC) and polypropylene carbonate (PPC) undergo depolymerization to ethylene carbonate (EC) and propylene carbonate (PC), respectively, in the presence of Li salt under annealing treatment. The decomposition reaction can explain the surprising high ionic conductivity recently reported for solid polymer electrolyte (SPE) polycarbonate-based systems. Because this phenomenon can strongly impact the results of SPE research, it is essential to control the depolymerization of polymers to avoid inaccurate electrochemical performance. In addition, we observed that the standard drying procedure for the preparation of high-salt-concentration polymer (polymer-in-salt) SPEs traps a high amount of residual solvent, e.g., acetonitrile (ACN), due to the strong bond between the solvent and ionic species. This finding represents another factor influencing the remarkably high ionic conductivity.

O3/P2-layered oxides, especially O3–NaCrO2, have been widely investigated as cathode materials for sodium-ion batteries due to their high stability and flexible synthesis procedure, but their low electron conductivity, the toxicity of Cr(VI) and cation disorder limit their applications. Here, we present O3–Na(Cr0.8Mn0.2)O2 as a promising cathode, which has a higher average storage voltage than O3–NaCrO2 and a practical useable capacity of ca. 100 mAh/g. The low volume change (~0.90%), lack of toxic Cr6+ formation and cation ordering in the optimized O3–Na(Cr,Mn)O2 structure ensure a potentially long cycle life. In situ XRD was used to monitor the phase formation at high temperature and to unveil the working mechanism of the O3–Na(Cr,Mn)O2 electrode during cycling. XAS and DFT investigations revealed variations in the local structure and the sequence of charge transfer of the transition metal during cycling. This work sheds light on the sodium storage mechanism of O3-layered oxides from micro- and electronic-structure points of view and reveals the role of transition metals in the working mechanism and performance.

All-solid-state lithium batteries (ASSLBs) are undoubtedly among the most promising technologies to replace conventional lithium-ion batteries. Their key component is a thin solid-state electrolyte, which is safer than its flammable liquid counterpart and enables the use of metallic lithium, thus ensuring high energy densities (over 500 W h kg−1). Several solid electrolytes are currently being investigated, such as NASICON-like materials, perovskites, and garnets. Typical techniques used to synthesize most such electrolytes still involve prolonged high-temperature calcination and sintering steps. An alternative approach is to couple electrospinning with the well-known sol–gel method to lower the temperatures and synthesis times and simultaneously exploit the benefits of using anisotropic nanostructured materials. In this review, we discuss advances in the synthesis of ceramic nanofibrous materials having high ionic conductivity and present our perspective regarding their potential application as electrolytes in ASSLBs. Keywords: Electrospinning, Solid electrolyte, Ceramic, Nanofibers, Lithium metal battery

We report the electrochemical properties of LiMnyFe1-yPO4 (0.5≤y≤0.8) cathode materials synthesized by hydrothermal route. Special attention was taken to optimize the carbon deposit on the surface of particles in order to make easy comparison of the electrochemical performance as a function composition with the same particle size. The substitution led to the modification of the electrochemical performance, such as initial capacity, capacity fading and polarization. We present the modified Peukert diagrams for C-rate in the range from C/12 to 40C.

Based on neutron powder diffraction (NPD) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), we show that calcium ions help eliminate the Fe-antisite defects by controlling the nucleation and evolution of the LiFePO4 particles during their hydrothermal synthesis. This Ca-regulated formation of LiFePO4 particles has an overwhelming impact on the removal of their iron antisite defects during the subsequent carbon-coating step since (i) almost all the Fe-antisite defects aggregate at the surface of the LiFePO4 crystal when the crystals are small enough and (ii) the concomitant increase of the surface area, which further exposes the Fe-antisite defects. Our results not only justify a low-cost, efficient and reliable hydrothermal synthesis method for LiFePO4 but also provide a promising alternative viewpoint on the mechanism controlling the nanosizing of LiFePO4, which leads to improved electrochemical performances. © 2016 American Chemical Society.

International audience; The authors focused on the preparation of thin layers based on hybrid materials (organometallic complexes) deposited onto glass substrates. The deposition experiments of [Ni(bpy)3](NCS)2, [Ni(bpy)3](Ag(CN)2)2, and [Ni(bpy)3](Fe(CN)5NO) were performed on glass slides (18 mm × 18 mm) by successive ionic layer adsorption and reaction (SILAR) method. The influence of some parameters, such as dipping cycle numbers (30, 60, and 120 dipping cycles), temperature (20°C, 30°C, 40°C, and 50°C), precursors concentration (10−3, 10−2, and 10−1 M), and the nature of the counteranions (NCS−, [Fe(CN)5NO]−2, [Ag(CN)2]−) were studied. Different methods (UV-Vis, SEM, FTIR, and XRD) were used to characterize the deposited layers to determine the absorption coefficient (α) and gap energy (Eg) of the materials.

International audience; We report the electrochemical properties of submicron-sized particles of NaFePO4. Two materials have been studied and characterized by XRD, SEM, EDX, EIS and Raman experiments: the maricite phase synthesized by hydrothermal method and the olivine phase obtained from delithiation of LiFePO4. NaFePO4 materials have an electrochemical activity in Na cell using NaPF6-EC-DEC electrolyte, but only in the heterosite phase, and the capacity is reduced already in the second cycle. The two-phase system at intermediate compositions has also been analyzed

Le present travail a pour objectif de reduire l’impact des colorants de cuve par une argile algerienne naturelle et activee en utilisant la technique d’adsorption. Les experiences d’adsorption montrent que l’argile utilisee est tres efficace dans l’elimination du colorant de cuve a des concentrations relativement faibles en milieu aqueux. Les isothermes d’adsorption du colorant de cuve sur l’argile brute sont decrites de maniere satisfaisante par le modele de Langmuir. Des capacites d’adsorption de l’ordre de 55,25 mg.g−1 pour la bentonite brute (BB), 55,20 mg.g−1 pour la bentonite sodique (BS), 51,78 mg.g−1 pour l’argile rouge (AR) et 48,24 mg.g−1 pour l’argile de Mâadid (AM) ont ete determinees a partir de l’isotherme de Langmuir. Ces valeurs montrent que la bentonite brute presente une meilleure capacite d’adsorption du fait qu’elle renferme un important pourcentage de fraction argileuse.

Lithium-insertion compounds with the spinel structure become active element of a new generation of Li-ion batteries, namely the 4.7-V positive electrodes that improve the technologies of energy storage and electric transportation. The compound considered here is the bulk and surface modified LiMn1.5Ni0.5O4 (LMN) spinel. We report the structural and electrochemical features of Cr-doped LMN phase and the LiFePO4-coated LMN structure. Emphasis is placed on the control of physical properties that is needed to guarantee the reliability and the optimum electrochemical performance of these materials.

We report that the rotation speed of the stirring in the hydrothermal reactor process is an important parameter that affects the structural properties and the electrochemical performance of LiFePO4. The best results are obtained for a rotation speed of 280 revolutions per minute. It is argued that this improved performance is related to the optimized morphology of the particles, and a smaller agglomeration of the particles. Since this material meets a worldwide success as a positive electrode for commercial Li-ion batteries.

We examine the reactivity of the non-aqueous electrolyte at the surface of 5-volts positive electrode materials for Li-ion batteries. LiPF6-based electrolytes include various solutes as ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC) and 1,2-dimethoxyethane (DME), which react with the surface of LiNi0.5Mn1.5O4 in the voltage range 3.0–4.9 V vs. Li0/Li+. Effects with mixed salts and electrolyte additive are also examined.

In situ X-ray diffraction has been carried out to study the structural changes of the bare and Cr-doped LiMn1.5Ni0.5O4 crystallized samples in the disordered phase (Fd m space group) are investigated during the galvanostatic charge/discharge process at C/24 rate. The de-intercalation of lithium proceeds through a series of first-order phase transitions with two regions of two-phase coexistence. The phase diagram is analyzed and discussed, together with the differences among different results reported in the literature.

International audience; LiFePO4 has emerged as the winning cathode material for a new generation of Li-ion batteries that are increasingly used for hybrid and electric vehicles, due to its remarkable electrochemical properties. The present review gives the state of the art in the understanding of the properties of this material and the other members of the same family. We discuss the effects of the decrease of the size of the particles down to circa 20 nm; some of them have been misunderstood or are still open questions. All of them are important to determine the trends in the research and development on this family of materials in the future. The cells' properties are also reviewed with both the graphite and more recently the Li4Ti5O12 anodes, the last one providing outstanding performance in terms of cycling life and power that make them promising not only for electric vehicles, but also to solve for intermittence locally in smart grids

The carbon-coated LiFePO 4 and C–Li 4 Ti 5 O 12 particles of 90 nm in diameter have been tested as active elements of electrodes of Li-ion batteries. The 18650-size cell using the usual electrolyte 1 mol L −1 LiPF 6 in ethylene carbonate (EC) and diethylene carbonate (DEC) displays a charge capacity of 650 mAh at low C-rate and retains more than 80% of rated capacity at 60C charge rate (1 min). 2032-size coin cells have been tested with different electrolytes: 1.5 mol L −1 lithium tetrafluoroborate LiBF 4 in EC+ γ-butyrolactone (GBL), and 0.5 mol L −1 lithium bis(trifluoromethanesulfonyl)imide (LiN(CF 3 SO 2 ) 2 , LiTFSI) + 1 mol L −1 LiBF 4 in EC + GBL, aiming to replace the less stable LiPF 6 salt. The LiTFSI-based electrolyte can be used owing to the low operating voltage that avoids the corrosion of the aluminum of the collector. This electrolyte shows the best results as the performance is even higher at 60 °C. The infrared images show that the temperature of the cell never reaches this temperature during cycling, making this battery a high-power battery with remarkable thermal stability. The maximum temperature reached by the cell is 34 °C at 40C-rate and 40 °C at 60C. The free EC-based electrolytes even operate at 80 °C by using 1 mol L −1 lithium bis(fluorosulfonyl)imide (LiFSI) in GBL or 1 mol L −1 LiFSI in PC + GBL, thus increasing importantly the operating temperature range for the battery. The carbon coated on LTO depresses the evolution of gases during charge discharge.