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[Display omitted] • 2D multilayered Ti 3 C 2 T x MXene adsorbents were fabricated via selective Al element etching. • Li+-intercalation increased the interlayer spacing and surface area. • TCF-2 exhibited broad working pH range and excellent Nd3+ adsorption capacity (517.8 mg/g). • The Nd3+/Fe3+ selectivity of TCF-2 reached 221. • The adsorption mechanism was elucidated using different characterizations. Recovering rare earth elements (REEs) from low-concentration REE-bearing waste streams has been deemed as a sustainable approach to diversity REE supply and reduce environmental burden. However, highly selective separation of trivalent Fe3+ and Al3+ impurities during low-concentration REE processing still remains a critical challenge. In this study, two-dimensional multilayered MXene adsorbents TCFs were successfully prepared and utilized for Nd3+ adsorption via selective etching of Al element in Ti 3 AlC 2. It was found that LiF/HCl-etched TCF-2 can simultaneously realize effective Al etching, interlayer spacing expansion and in-situ Li+ intercalation. The intercalated Li+ amount was up to 4.44 wt% (6.40 mmol/g). Compared with HF-etched TCF-1, TCF-2 demonstrated boosted adsorption kinetics (2 h), large adsorption capacity (517.79 mg/g), impressively high selectivity (Nd3+/Fe3+ SF = 221, Nd3+/Ca2+ SF = 858, Nd3+/Mg2+ SF = 3545), and broad working pH range (2–7). Various experimental characterizations reveal that selective Nd3+ recovery is owing to the ion-exchange and surface complexation induced by interlayer Ti-O/Ti-OH of TCF-2. Specifically, the extended X-ray sorption fine structure (EXAFS) results, in combination with density functional theory (DFT) calculations, further confirm the Nd3+ is selectively adsorbed by forming surfaced complexes structure in the interlayer. And this is also evidenced by the decrease of Nd-O distances and high coordination number. The present results illustrate that alkaline metal ion-intercalated MXene could serve as a promising candidate to efficiently remove trivalent Fe3+ impurities for REEs recovery. [ABSTRACT FROM AUTHOR]

Lithium ion (Li+) aggregation in the amorphous tungsten oxide (a-WO x) film is the main cause of the electrochromic (EC) device failure. This has hindered a-WO x films goes towards industrialization on behalf of the giant EC performance and long-term reliability. A novel kind of electrolytes consisted of Aluminum ions (Al3+) and Lithium ions (Li+) used for electrochromic sputtered a-WO x films is presented. With the newly designed Al3+/Li+ co-existed electrolytes, the optical transmittance modulation can be largely enhanced compared with Li+, meanwhile, the problem of degradation after long-term cycling for a-WO x induced by Li ions-trapping is able to be solved. Furthermore, the utilization of Al3+ brings slow switching kinetics at the ions extraction step to the films compared with Li+, which supplies a new method to modulate the bleaching rate by applying adjustable Al3+/Li+ ratio of electrolytes and a tunable and controllable switching time is easily achieved in this work. This Al3+/Li+ co-based electrolyte opens a new way to design and control the high contrast, long-lived cycling stability and changeable switching time EC devices based on a-WO x films. [ABSTRACT FROM AUTHOR]

Herein, we reported a facile method to synthesize the nanostructured vanadium oxides by electrochemical deposition, followed by thermal treatment. Polymer surfactant was selected as a template agent to control the nanostructures. Nanorod-, nanoparticle- and platelet-structured vanadium oxides with different sizes were obtained by simply changing the surfactant concentrations. The crystallinity of various nanostructured vanadium oxide was confirmed by X-ray diffraction. X-ray photoelectron spectroscopic analysis reveals a mixed valence nature of vanadium specie in which the amount of V(V) and V(IV) species is not significantly affected by varying the surfactant concentrations. Cyclic-voltammetry curves show that the smallest potential separation between the cathodic and anodic peaks for the nanorod-structured vanadium oxide. The nanorod-structured vanadium oxide exhibits excellent Li-ion intercalation properties, much better than that of the nanoparticle- and platelet-structured vanadium oxides. Thus, the excellent performance with low-cost make the nanorod-structured vanadium oxide promising potential as a cathode material for the Li-ion battery applications. [ABSTRACT FROM AUTHOR]

The creation of new environmentally friendly and portable energy sources requires the development of technology used to produce lithium-ion batteries, especially their anodes. The aim of this study was to show the possibilities of the state-of-the-art ab initio approach for modeling battery anode materials. A quantum-mechanical study of the limiting filling of a silicene/aluminum anode with lithium has been performed. In this case, the changes in the structure, energy, and electronic properties of silicene that occur upon filling the anode have been studied. Lithium atoms are deposited both inside and on top of the channel formed by two parallel silicene sheets. The ratio of lithium to silicon varies in the range of 0.1–1.5. The gap in the silicene channel increases as the channel is filled with lithium. The filling of the silicene channel with lithium is associated with an increase in the Si–Si bond length in both silicene sheets without destruction of the channel. The infiltration of lithium into the space between the aluminum substrate and silicene sheet has been determined. Our calculation of the band structure has shown that, regardless of filling with lithium, the silicene-aluminum system exhibits metallic conductivity. The storage capacity of the combined anode (729 mAh g−1) significantly exceeds the capacity of graphite anodes. It was found that the top sheet of silicene acquires a negative electric charge upon significant lithium filling of the anode, exceeding the absolute value of the negative charge of the bottom sheet in contact with the aluminum substrate. Therefore, our model study has elucidated that the new silicene-aluminum anode is a promising material for the creation of a new generation of lithium-ion batteries. • The limiting filling of silicene/aluminum anode with lithium first investigated. • Ab initio molecular dynamics calculations were performed at 293 K. • The new result is a calculated capacity (729 mAh g−1) of the silicene/Al anode. • The silicene-Al system exhibits metallic conductivity even in the absence of Li. [ABSTRACT FROM AUTHOR]

The adsorption of CO 2 and H 2 O on divacanacy (DV) defected graphene cluster, and its bilayer counterpart is investigated using first-principles calculations. Both single and bilayer DV graphene cluster, are functionalised with H and F atoms. On these sheets the gas molecules are physisorbed, and the divacancy defect effectively improves the adsorption of CO 2 , while fluorination enhances the hydrophobicity of the graphene cluster. Among the convex and concave curvature regions induced due to the DV defect, the adsorption of the gas molecules on the concave meniscus is more favourable. Fluorine termination induces 73% reduction in Henry law constants for H 2 O, while for the CO 2 molecule it increases by 8%, which indicates the DV defective sheet is a better candidate for CO 2 capture compared to the STW defective sheet. Besides, both AA and AB divacant defect bilayer sheets are equally stable, wherein AA stacking results in a cavity between the sheets, while in AB stacking, the layers slide one over the other. Nevertheless, both these bilayer sheets are comparatively stabler than the monolayer. However, intercalation of lithium decreases the interlayer separation, particularly in AA stacking, which enhances the CO 2 adsorption, but in the Bernal stacking enhances it hydrophobicity. [ABSTRACT FROM AUTHOR]

Several spent Li-ion batteries were manually dismantled and their components were uncurled and separated. The chemical composition of each battery's component was determined by atomic absorption spectroscopy. Among several ways to separate cathode material from the collector, the alkali dissolution treatment was selected as the most effective one. After both complete separation and acid leaching steps, the co-precipitation method, followed by a thermal treatment (700 °C or 850 °C), was used to resynthesize cathode material LiCo 0.415 Mn 0.435 Ni 0.15 O 2 . Its structure and morphology were characterized by XRD, Raman spectroscopy and SEM-EDS methods. The electrochemical behavior of recycled cathode materials was examined by cyclic voltammetry and chronopotentiometry in both LiNO 3 and NaNO 3 aqueous solutions. High sodium storage capacity, amounting to 93 mAh g −1 , was measured galvanostatically at a relatively high current of ∼100 mA g −1 . Initial lithium intercalation capacity of ∼64 mAh g −1 , was determined potentiodynamically at very high scan rate of 20 mV s −1 (∼40 C). Somewhat lower initial capacity of ∼30 mAh g −1 , but much lower capacity fade on cycling, was found for sodium intercalation at the same scan rate. The differences in the Li and Na charge storage capability were explained in terms of ion rearrangement during charging/discharging processes. [ABSTRACT FROM AUTHOR]

In this work, lithium plating is investigated by means of voltage relaxation and in situ neutron diffraction in commercial lithium-ion batteries. We can directly correlate the voltage curve after the lithium plating with the ongoing phase transformation from LiC 12 to LiC 6 according to the neutron diffraction data during the relaxation. Above a threshold current of C/2 at a temperature of −2 °C, lithium plating increases dramatically. The results indicate that the intercalation rate of deposited lithium seems to be constant, independent of the deposited amount. It can be observed that the amount of plating correlates with the charging rate, whereas a charging current of C/2 leads to a deposited amount of lithium of 5.5% of the charge capacity and a current of 1C to 9.0%. [ABSTRACT FROM AUTHOR]

LiNbO 3 -coated LiNi 0.5 Mn 1.5 O 4 powders were synthesized by a sol–gel method, and their intercalation property as a cathode material was investigated using all-solid-state batteries with Li 10 GeP 2 S 12 solid electrolyte and In–Li metal anode. The LiNbO 3 coating delivered reversible lithium intercalation of LiNi 0.5 Mn 1.5 O 4 through an electrochemical interface with the Li 10 GeP 2 S 12 . Oxygen-deficient LiNi 0.5 Mn 1.5 O 4 − δ with a higher electronic conductivity than LiNi 0.5 Mn 1.5 O 4 improved the intercalation activity. An all-solid-state battery consisting of 3 wt.%-LiNbO 3 -coated LiNi 0.5 Mn 1.5 O 4− δ /Li 10 GeP 2 S 12 /In–Li exhibited a discharge capacity of 80 mAh g − 1 at the first cycle with an average discharge voltage of 4.1 V (vs. In-Li), which demonstrates the possibility of 5 V class all-solid-state batteries with a high voltage spinel cathode. [ABSTRACT FROM AUTHOR]

Materials based on layered LiVO 2 are mostly considered as a potential anodes for Li-ion batteries, competitive to commonly used graphite. They can also act as cathode materials, however there are almost no studies on this subject. LiVO 2 and it delithiated derivatives were widely studied during 80s and 90s of the 20th century mainly because of its magnetic properties. This work presents evaluation of crystal structure, oxygen nonstoichiometry, transport and electrochemical properties of Li(Li y Fe z V 1 − y − z )O 2 − δ group of materials, with special insight to their possible application as cathode materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]

A high concentration of lithium, corresponding to charge capacity of ∼4200 mAh/g, can be intercalated in silicon. Unfortunately, due to high intercalation strain leading to fracture and consequent poor cyclability, silicon cannot be used as anode in lithium ion batteries. But recently interconnected hollow nano-spheres of amorphous silicon have been found to exhibit high cyclability. The absence of fracture upon lithiation and the high cyclability has been attributed to reduction in intercalation stress due to hollow spherical geometry of the silicon nano-particles. The present work argues that the hollow spherical geometry alone cannot ensure the absence of fracture. Using classical molecular dynamics and density functional theory based simulations; satisfactory explanation to the absence of fracture has been explored at the atomic scale. [ABSTRACT FROM AUTHOR]

Graphite anode behaviour is of great interest for the optimization of Lithium-ion batteries. The improvement of battery performance depends on an understanding of lithium intercalation/de-intercalation in graphite anodes, especially in regards to energy and power density. In this study we present a new approach for investigating graphite anode behaviour under equilbirum and nonequlibirum conditions. It is based on reflectance change measurements from a graphite anode surface, relative to state of charge (SOC). We have introduced an innovative optical test cell and used a photodiode. A reflectance change hysteresis occurs between lithium intercalation and de-intercalation, under equilbrium conditions. This was ascribed to specific lithium-carbon bonds at the graphite particle edge region. Charging and discharging have a unique reflectance change characteristic. This was assigned to SOC nonequilibrium in the anode and serves as clear evidence that limited lithium mobility in the porous microstructure is a signficant loss factor. We then performed a more detailed analysis of the anode loss processes by correlating the anode reflectance change with dynamic electrical excitation. This method, Optical Impedance Spectroscopy (OIS), provided detailed information about the frequency range of the loss processes. It also confirmed our assigning the low frequency range (1 mHz-3 Hz) to solid state diffusion and lithium transport in the electrolyte filled pores. The results are in excellent agreement with previous EIS studies. We conclude that OIS is applicable for validating physicaly-based graphite anode models and determining model parameters, in combination with EIS. [ABSTRACT FROM AUTHOR]

We test the stability of pre-lithiated graphite anodes for Li-ion batteries in a dry room battery processing room. The reaction between LiC x and laboratory air was followed using operando NMR and x-ray diffraction, as these methods are sensitive to change in Li stoichiometry in graphite. There is minimal reactivity between LiC 6 and N 2 , CO 2 or O 2 ; however, LiC 6 reacts with moisture to form lithium (hydr)oxide. The reaction rate follows zero-order kinetics with respects to intercalated lithium suggesting that lithium transport through the graphite is fast. The reaction occurs by sequential formation of higher stages–LiC 12 , then LiC 18 , and then LiC 24 –as the hydrolysis proceeds to the formation of Li x OH y and graphite end products. Slowing down the formation rate of the Li x OH y passivation layer stabilizes of the higher stages. [ABSTRACT FROM AUTHOR]

The electrochemical reaction with lithium of a vanadium-based metal-organic framework V IV (O)(bdc) [MIL-47], which is isostructural to the iron compound MIL-53(Fe), was investigated. The large open channels which can accommodate small guest species, such as Li + ions, together with the redox properties of the tetravalent vanadium ions make this material of potential interest as a rechargeable intercalation electrode for lithium batteries. The electrochemical properties were investigated in Li|1 M LiPF 6 in ethylene carbonate (EC) and dimethyl carbonate (DMC)|V(O)(bdc) cells between 4.0 and 1.5 V vs. Li/Li + . V(O)(bdc) cathodes can be reversibly cycled in Li cells with good rate capability and specific capacity. At a current density of C /12, Li/V(O)(bdc) cells can be cycled between 0 ≤ x ≤ 0.7 in Li x V(O)(bdc) with ∼100% coulombic efficiency corresponding to 82 mAh g −1 which is a higher capacity than that found for MIL-53(Fe). The cell performance and electrochemical profiles at various current conditions are discussed. Structural evolution taking place during lithium intercalation was monitored by powder X-ray diffraction on phases of Li x V(O)(bdc) (0 < x ≤ 2) chemically prepared by using n-BuLi. Previous studies of the reaction of lithium with metal-organic frameworks are briefly reviewed for comparison with the data presented for Li x V(O)(bdc). [ABSTRACT FROM AUTHOR]

Lithium insertion in FeNb 2 O 6 and CrNb 2 O 6 has been investigated using the galvanostatic charge–discharge method and showed that more than half of the intercalated Li + during first cycle is retained in the structure and is not de-intercalated during subsequent cycles. The effects of sintering on FeNb 2 O 6 were investigated with lower applied temperatures yielding higher Li + intercalation capability. Post galvanostatic XRD shows that the initial phase has been retained during cell cycling. Cyclic voltammetry reveals that chromium also takes part in electro-chemical activity in CrNb 2 O 6 . [ABSTRACT FROM AUTHOR]

Calcium manganate Ruddlesden–Popper phases Ca 2 MnO 4–δ were prepared by soft chemistry and treated with acid to extract a part of the calcium ions. Combined structural, morphological and spectroscopic analyses by XRD, SEM/EDX, TEM and Raman revealed an amorphization of the treated surface with a preserved inner crystalline phase in the core of the particles. The inner part of the particles consists of Ca 2 MnO 4–δ and the outer part of hydrated amorphous manganese oxide MnO 2 ·xH 2 O. Although pristine Ca 2 MnO 4–δ is not electrochemically active, electrochemical characterization of the acid-treated powders shows a significant change in capacity that correlates to the amount of extracted calcium. The cycling stability of the Ca 2 + extracted compounds was improved by more than a factor of 10 in comparison to pure MnO 2 ·xH 2 O. The acid-treated Ca 2 MnO 4–δ showed enhanced capacity retention of up to 50% after 70 cycles compared to 4% for bare MnO 2 ·xH 2 O due to its crystalline core. [ABSTRACT FROM AUTHOR]

Recently, layered Li1+xV1−xO2 with x≥0 has attracted significant attention as an anode material for Li-ion batteries. Its high volumetric and gravimetric capacities (1360mAh·cm−3 and 300mAh·g−1 respectively) make it particularly interesting. During lithium intercalation Li1+xV1−xO2 with x>0 exhibits wide potential plateau below 0.1V vs. Li/Li+, while for stoichiometric LiVO2 lithium uptake hardly occurs. In this work evaluation of crystal structure, transport and electrochemical properties is given for Li1+xV1−xO2 materials with x=0, 0.03 and 0.07. Li1+xV1−xO2 showed activated character of conductivity with activation energy about 0.2–0.3eV. Thermoelectric power values exceeding 80μV·K−1 point to electron holes as the main charge carriers. Thermogravimetric measurements carried out in air indicated only minor variations of mass of the materials up to 215°C, suggesting high stability along with low level of oxygen nonstoichiometry. [ABSTRACT FROM AUTHOR]

Influence of the ultrasound on talc (Mg 3 Si 4 O 10 (OH) 2 ) cathode material was experimentally investigated. The Gibbs׳ energy change of the Li + - intercalation process, the diffusion coefficient in Li x Mg 3 Si 4 O 10 (OH) 2 , the charge transfer resistance and the capacitance of the electric double layer were studied in electrochemical cells, based on initial and ultrasonic treated talc. The obtained results were interpreted within the nonlinear diffusion-deformation model, which involved formation of vacancy nanoclusters under ultrasonic influence at temperatures lower than a critical value. [ABSTRACT FROM AUTHOR]

Abstract: Lithium battery performances degrade even at rest time that means when electric/hybrid electric vehicles are in the parking. This phenomenon is well known as calendar aging. In this paper, the kinetic of the CC–CV charge at 1 C and mainly kinetic of the voltage regulation, CV step, is investigated as an indicator of battery state-of-health through calendar aging. In fact, CV step is responsible in a major part of lithium intercalation into negative electrode and revealed to give signification on cyclable lithium loss which is the major cause of calendar aging according to literature and post mortem analysis. Comparison from the aging of four battery technologies is presented. Through aging, results show a difference in battery behavior even if the time for CC charge is decreasing for all the battery. According to battery technology, the current during CV charge phase has been useful for lithium–nickel–manganese–cobalt-oxide, lithium–nickel–cobalt–aluminum-oxide and lithium-ion–manganese battery state-of-health determination. However, in the case of the lithium–iron–phosphate battery, simple calculation of the duration of the CV step revealed to be very accurate compared to the classic discharged capacity measurement. [Copyright &y& Elsevier]

Abstract: Electrochromic (EC) devices show a promise to be the next major advance in the energy-efficient window technology. However, the development of higher value (performance and cost) EC windows is the key to promote the applications of these energy saving devices. To that end, computer modeling may play a powerful role in providing in-depth understanding in EC device design, performance enhancement, material selection and development of EC layers. In this work, we describe a 2D time-dependent finite element based solver, established to simulate large area Li ion electrochromic devices. The results of 2D-model development and corresponding simulations are presented utilizing literature-based material properties. The capability of the model is demonstrated in handling a very large width-to-thickness aspect ratio and examining the impacts of a voltage change due to the spreading resistance and a diffusivity variation inside electrodes on device performance and lithium ion transport kinetics. [Copyright &y& Elsevier]

Abstract: Layered sulfides, 2H-Li0.7NbS2 (s.g.: P63 /mmc) and 3R-NbS2 (s.g: R3m) were synthesized and characterized as electrode materials for a lithium-ion battery. 2H-NbS2 has been known as a poor electrode material for Li+-intercalation. However, both 2H-Li0.7NbS2 and 3R-NbS2 show reversible charge/discharge reactions based on the Nb(IV)/Nb(III) redox couple. They present distinctive differences in the voltage curves as a result of local structural differences. Galvanostatic charge/discharge tests between 1.0 and 3.0 V versus Li showed that discharge capacities were 169.5 mAh g−1 for 2H-Li x NbS2 and 169.0 mAh g−1 for 3R-Li x NbS2 at 0.05 C rate and room temperature. At 10 C rate, 2H-Li x NbS2 delivered a discharge capacity of 84.0 mAh g−1 while 3R-Li x NbS2 kept 74.9 mAh g−1. After 200 cycles at 1 C, 9% of capacity fade was observed for 2H-Li x NbS2 (from 141.5 to 129.4 mAh g−1) and 3R-Li x NbS2 showed 14% fade from 139.4 to 120.1 mAh g−1. The key to improvement of the electrochemical performance of the 2H-Li x NbS2 electrode is an initial synthesis of Li0.7NbS2. [Copyright &y& Elsevier]

Abstract: Electrochemical impedance spectroscopy (EIS) was applied to quantify and characterize different compositions of layered LiCoO2 electrodes fabricated with different carbon nanotubes (CNTs) additions and fixed binder content. Different LiCoO2/CNT ratios in aqueous solutions resulted in charge transfer and capacitance behavior at the interface. The CNT particles influenced the interfacial mechanisms; low scan rates revealed non reversible reactions, and different electrode compositions influenced the functionality of the particles according to the LiCoO2/CNTs ratios and surface characteristics. Cyclic voltammetry (CV) helped to determine the active state and identify the important potential peaks when LiCoO2 is mixed with CNT. A deterministic model based upon the impedance signal was performed; lithium intercalation inside the composite cathode is normalized and included in the faradaic current. Conservation of charge is considered for the cathodic process by a balance of the charge–discharge natural process on the electrode introducing kinetic parameters that describe the interfacial behavior. The model was validated with experimental data demonstrating the influence of the CNT in the capacitive mechanisms. [Copyright &y& Elsevier]

Highlights: [•] Electrochemical stability of single wall carbon nanotube (SWCNT) modified Pt electrodes. [•] Li charging/discharging at SWCNT/4-aminothiophenol/Pt electrodes. [•] SWCNT/4-aminothiophenol/Pt higher Li charge density than graphite electrodes. [ABSTRACT FROM AUTHOR]

Abstract: A new material, LiRu2O4, has been synthesized by ion-exchange reaction from NaRu2O4 that has been prepared by solid state reaction at 950 °C under Ar flow. The crystal structure of LiRu2O4, isostructural with the parent NaRu2O4, has been refined by an X-ray Rietveld method (Pnma, a = 9.13940(5) Å, b = 2.80070(9) Å, c = 11.0017(1) Å, Z = 4, R p = 5.30%, wR p = 6.73%, χ 2 = 0.41, 23 °C). The structure belongs to CaFe2O4-type, where double chains of edge-sharing octahedral RuO6 share the corners with neighboring double chains and form tunnels in between them parallel to the shortest b-axis so that the one-dimensional Li array is placed inside each of the tunnels. Detailed structural analysis indicates that the tunnel inside has more than enough space to be filled with the Li atoms. The electrochemical tests of LiRu2O4 demonstrates a reversible Li intercalation reaction at 3.2–3.5 V vs. Li/Li+ with a capacity of ∼80 mAhg−1. The material exhibits excellent high-rate characteristics (93% capacity retention at 10C/1C) as well as high capacity retention with cycles (99% at 50 cycles). [Copyright &y& Elsevier]

Abstract: H2V3O8 nanobelts have been successfully synthesised from commercial V2O5 powder through a fast and environmental friendly microwave-hydrothermal method. X-ray diffraction, field-emission scanning electron microscopy, thermogravimetric analysis, infrared spectroscopy, high-resolution transmission electron microscopy and ICP spectroscopy were used to characterise the morphology and structure–microstructure details. Nanobelts about 100 nm wide and several micrometres long are easily prepared in no more than 2 h. The electrochemical study reveals the reversible insertion of ca. 4 Li per formula unit (400 mAh g−1), through several pseudo-plateaus in the 3.75–1.5 V vs Li+/Li voltage range showing the interest of this material produced by a “green” route as an electrode for lithium rechargeable batteries. After the first cycle a significant capacity loss is observed, though a high capacity, ca. 300 mAh g−1, remains upon cycling. Furthermore, the similarity of discharge and charge curves, pointing to the absence of hydrogen displacement during lithium insertion in H2V3O8, shows that not all protonated systems must be discarded as prospective electrode materials. On the other hand, further reduction down to 1 V is possible to insert up to 5 Li per formula unit (480 mAh g−1). Interestingly it corresponds to full reduction of vanadium to V3+ as it is also confirmed by EELS experiments. However, the full reduction to V3+ is associated with a fast decay of the extra capacity developed at low voltage with increasing current rate. Then for practical use we may consider only the capacity obtained down to 1.5 V. [Copyright &y& Elsevier]

Electrochemical lithium intercalation within graphite from 1moldm−3 solution of LiClO4 in propylene carbonate (PC) was investigated at 25 and −15°C. Lithium ions were intercalated into and de-intercalated from graphite reversibly at −15°C despite the use of pure PC as the solvent. However, ceaseless solvent decomposition and intense exfoliation of graphene layers occurred at 25°C. The results of the Raman spectroscopic analysis indicated that the interaction between PC molecules and lithium ions became weaker at −15°C by chemical exchange effects, which suggested that the thermodynamic stability of the solvated lithium ions was an important factor that determined the formation of a solid electrolyte interface (SEI) in PC-based solutions. Charge–discharge analysis revealed that the nature of the SEI formed at −15°C in 1moldm−3 of LiClO4 in PC was significantly different from that formed at 25°C in 1moldm−3 of LiClO4 in PC containing vinylene carbonate, 3.27molkg−1 of LiClO4 in PC, and 1moldm−3 of LiClO4 in ethylene carbonate. [ABSTRACT FROM AUTHOR]

Abstract: Acid treated montmorillonite K-10 (MK-10) was intercalated with LiOH (Li/MK-10) to catalyze selective production of diglycerol via solvent free glycerol etherification reaction. The structure, surface properties and basic strength of parent and modified clay were successfully characterized using XRD, SEM, ICP, BET surface analyzer and Hammett indicators to elucidate their physical and chemical properties. The glycerol etherification reaction was conducted at 240°C with 2wt.% lithium intercalated catalyst under inert atmosphere. High diglycerol selectivity of about 53% was obtained in 12h with this catalyst at a glycerol conversion of about 98%. [Copyright &y& Elsevier]

Abstract: In this contribution a novel powder coating processing technique (microblasting) for the fabrication of nickel oxide (NiO x ) coatings is reported. ∼1.2μm thick NiO x coatings are deposited at 20mm2 s−1 by the bombardment of the NiO x powder onto a Ni sheet using an air jet at a speed of more than 180ms−1. Microblast deposited NiO x coatings can be prepared at a high processing rate, do not need further thermal treatment. Therefore, this scalable method is time and energy efficient. The mechano-chemical bonding between the powder particles and substrate results in the formation of strongly adherent NiO x coatings. Microstructural analyses were carried out using SEM, the chemical composition and coatings orientation were determined by XPS and XRD, respectively. The electroactivity of the microblast deposited NiO x coatings was compared with that of NiO x coatings obtained by sintering NiO x nanoparticles previously sprayed onto Ni sheets. In the absence of a redox mediator in the electrolyte, the reduction current of microblast deposited NiO x coatings, when analyzed in anhydrous environment, was two times larger than that produced by higher porosity NiO x nanoparticles coatings of the same thickness obtained through spray coating followed by sintering. Under analogous experimental conditions thin layers of NiO x obtained by using the sol–gel method, ultrasonic spray- and electro-deposition show generally lower current density with respect to microblast samples of the same thickness. The electrochemical reduction of NiO x coatings is controlled by the bulk characteristics of the oxide and the relatively ordered structure of microblast NiO x coatings with respect to sintered NiO x nanoparticles here considered, is expected to increase the electron mobility and ionic charge diffusion lengths in the microblast samples. Finally, the increased level of adhesion of the microblast film on the metallic substrate affords a good electrical contact at the metal/metal oxide interface, and constitutes another reason in support of the choice of microblast as low-cost and scalable deposition method for oxide layers to be employed in electrochemical applications. [Copyright &y& Elsevier]

Abstract: We report single-crystalline TiO2 nanowires (TiO2-NWs) synthesized by hydrothermal process without any surfactant and template with enhanced lithium intercalation properties. The single-crystalline nature of rutile TiO2-NWs was clearly observed by field-emission transmission electron microscopy and fast Fourier transform pattern demonstrating that the nanowire growth is along the [001] direction. The single-crystalline rutile TiO2-NWs showed much higher charge capacity and excellent high-rate performance as compared to typical rutile TiO2 nanoparticles. The improved lithium-ion intercalation properties of TiO2-NWs may be attributed to relatively large specific surface area, short transport distance of 1-D nanostructure, and freedom for volume change accompanied by lithium-ion intercalation. [Copyright &y& Elsevier]

Abstract: A hybrid LiC capacitor combining a lithium-ion battery type (graphite) electrode and an electrical double-layer (activated carbon) one has been developed by preloading graphite from 2molL−1 lithium bis(trifluoromethane)sulfonimide (LiTFSI) organic electrolyte. The graphite intercalation compound was formed by applying ca. 10 successive charge/self-discharge pulses. The optimized hybrid device operates in the voltage range from 1.5 to 4.2V and displays 60% higher gravimetric capacitance than an electric double-layer (EDL) capacitor using the same activated carbon for both electrodes. As a result, the energy density reaches 80Whkg−1, which is four times higher than the value for the EDL capacitor with the same total mass of carbon. [Copyright &y& Elsevier]

Abstract: As a new molecular cluster cathode material for lithium batteries, K5.72H3.28[PV14O42] (KPV), a hetero polyoxovanadate with a bi-capped Keggin structure, was synthesized. Its crystal structure was refined by X-ray Rietveld analysis, and its electrochemical properties were examined. The symmetry space group of KPV was assigned to FM3-M. The [PV14O42]9− bi-capped Keggin units are connected sharing K+ ions. KPV contains many cation site vacancies and has tunnels facing various directions. The polycrystalline KPV powder becomes amorphous when dried at 80 °C, while the molecular cluster structure of KPV, identified by Raman scattering method, is maintained. KPV showed higher discharge capacity with higher discharge voltage than K3[PMo12O40] (KPM) with Keggin-type structure. The most improved property of KPV compared with KPM was cycle stability. KPV kept 95% of its initial discharge capacity after 50 cycles of discharge–charge, whereas KPM kept only 35%. The presence of bi-capped Keggin unit is confirmed by ex situ EXAFS measurement, even though a rapid amorphization of KPV was observed at the beginning of the discharge–charge process in ex situ X-ray diffraction (XRD) measurements. The results of ex situ EXAFS measurement and the reversible charge transfer resistance of KPV estimated from the AC-impedance measurement during the discharge–charge process also indicate that the cycle stability of KPV is attributable to the stability of the KPV cluster ion unit. [Copyright &y& Elsevier]

Abstract: The effect of Li+ insertion into different sized TiO2 nanoparticles and their influences on the photoconversion efficiency of dye-sensitized solar cells (DSSC) were investigated. TiO2 nanoparticles with different particle sizes (22nm, 14nm and 6nm) doped with Li+ were employed to form thin film electrodes and their properties were characterized by X-ray diffraction (XRD) and electrochemical impedance spectroscopy analysis. XRD evidenced the presence of anatase as the main phase. From the XRD analysis, it was observed that the Li+ ions could be inserted into both the surface and bulk of the TiO2 nanoparticles. In the larger particle size, the Li+ ions are inserted into the bulk anatase where as Li+ ions bounded on the TiO2 surface for the smaller crystallite size. The photovoltaic properties were measured by a current–voltage meter under AM1.5 simulated light radiation. It exhibited that the overall photoconversion efficiency of DSSC was decreased in the larger particles while it was enhanced in the smaller nanoparticles when Li+ was doped into the TiO2 nanoparticles. A nearly 40% decrease in the efficiency (η) of DSSC was observed upon intercalation of Li+ ions into 22nm sized TiO2 nanoparticles (P25). The 14nm sized TiO2 nanoparticles (P90) showed slightly less efficiency (η) upon Li+ doping than that of the undoped sample. However, the smallest sized TiO2 nanoparticles (6nm) showed higher efficiency than that of the undoped one. This phenomenon is explained based on electron trapping and charge recombination due to lithium doping. [Copyright &y& Elsevier]

Abstract: Electrochemical properties of graphite electrode are studied in propylene carbonate (PC) electrolytes containing both LiN(SO2CF3)2 and Ca(N(SO2CF3)2)2 salts, and the influence of the salt concentrations on the intercalation/de-intercalation properties of graphite electrode is clarified. In the higher concentration electrolytes, reversible lithium-ion intercalation/de-intercalation at graphite electrode takes place. In contrast, only the exfoliation of graphite occurs in the lower concentration electrolytes. The effect of the salt concentrations on the electrochemical properties of graphite is discussed. [Copyright &y& Elsevier]

Abstract: The thin film Sn–Co–Ni alloy electrodes were prepared by electroplating on copper foil as current collector. The structure of the electroplated porous thin film Sn–Co–Ni alloy electrode is investigated by XRD, FE-SEM, and EDAX. The electrochemical performance is analyzed by using a battery cycler at the current rate of 0.1C to cut-off potentials of 0.01 and 1.20V vs. Li/Li+ and also cyclic voltammeter. Experimental results illustrate that the initial discharge capacity of the Sn–Co–Ni alloy anode is 717mAhg−1. The discharge capacity has been in increasing order between 2nd and 10th cycling and then maintained the stable capacity. It is found that the charge and discharge capacity of thin film Sn–Co–Ni alloy electrode obtained an average reversibility behavior and the better cycle stability. [Copyright &y& Elsevier]

Abstract: The electrochemical property of Keggin type hetero polyoxomolybdate K3[PMo12O40] (KPM) as the cathode electrode material for lithium battery was examined. KPM showed charge–discharge performance in the potential region from 4.2V to 1.5V with capacity of over 200mAhg−1. From the result of the ex situ XRD measurement, it is presumed that the electrochemical reaction of KPM proceeds via the lithium (de-)intercalation. The cycle performance of KPM is largely dependent on the charge–discharge potential range. The capacity fade caused by deep discharging seems to be concerned to the 〈 to ® isomerization of KPM. [Copyright &y& Elsevier]

Abstract: Highly porous nickel oxide (NiO) thin films were prepared on ITO glass by chemical bath deposition (CBD) method. SEM results show that the as-deposited NiO film is constructed by many interconnected nanoflakes with a thickness of about 20nm. The electrochromic properties of the NiO film were investigated in a nonaqueous LiClO4–PC electrolyte by means of optical transmittance, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The NiO film exhibits a noticeable electrochromic performance with a variation of transmittance up to 38.6% at 550nm. The CV and EIS measurements reveal that the NiO film has high electrochemical reaction activity and reversibility due to its highly porous structure. The electrochromic (EC) window based on complementary WO3/NiO structure shows an optical modulation of 83.7% at 550nm, much higher than that of single WO3 film (65.5% at 550nm). The response time of the EC widow is found to be about 1.76s for coloration and 1.54s for bleaching, respectively. These advantages such as large optical modulation, fast switch speed and excellent cycle durability make it attractive for a practical application. [Copyright &y& Elsevier]

Abstract: Poly(acrylic acid) (PAA), poly(methacrylic acid) (PMA), and poly(vinyl alcohol) (PVA), which have oxygen species as functional groups, were utilized as a binder for graphite electrodes, and the electrochemical reversibility of lithium intercalation was examined in PC medium and ionic liquid electrolyte, lithium bis(trifluoromethanesulfonyl)amide dissolved in 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)amide (BMP-TFSA). Columbic efficiency of 75–80% with more than 300mAhg−1 was achieved upon first reduction/oxidation cycle in both electrolytes using these binding polymers, which were significantly improved in comparison to a conventional PVdF binder (less than 45% of columbic efficiency for the first cycle). For the graphite-PVdF electrode, co-intercalation and/or decomposition of PC molecules solvating to Li ions were observed by the electrochemical reduction, resulting in the cracking of graphite particles. In contrast, the co-intercalation and decomposition of PC molecules and BMP cations for the first reduction process were completely suppressed for the graphite electrodes prepared with the polymers containing oxygen atoms. It was proposed that the selective permeability of lithium ions was attained by the uniform coating of the graphite particles with PAA, PMA, and PVA polymers, because the electrostatic interaction between the positively charged lithium ions and negatively charged oxygen atom in the polymer should modulate the desolvation process of lithium ions during the lithium intercalation into graphite, showing the similar functions like artificial solid-electrolyte interphase. [Copyright &y& Elsevier]

Abstract: MnV2O6 nanobelts have successfully been synthesized via a hydrothermal route. The obtained nanobelts are highly crystalline and their thickness is found to be ca. 20–30nm. These nanobelts were first used as the anode materials in a rechargeable lithium-ion battery, which exhibits a very reversible discharge/charge capacity and excellent cycling stability even at a current density as high as 1Ag−1. This might be attributed to the intrinsic characteristics of MnV2O6 nanobelts. [Copyright &y& Elsevier]

Abstract: In this study, orthorhombic LiMnO2 nanoplates have successfully been synthesized via a simple hydrothermal route. The synthesized nanoplates are highly crystalline and their thickness is found to be ca. 10–50nm. A lithium battery using LiMnO2 nanoplates as the active materials of the electrode exhibits a second discharge capacity of 235mAhg−1 at a current density of 0.01Ag−1. Cycling test indicates that the electrode composed of LiMnO2 nanoplates shows a high reversible charge/discharge capacity and relative stable cycling performance. [Copyright &y& Elsevier]

Abstract: Titanium dioxide based tubular nanocomposites containing long-chain amines were prepared by hydrothermal reaction of anatase with neutral surfactants, dodecylamine and octadecylamine, under strong alkaline conditions. Morphologically pure phases are obtained after reaction times of about 50h at 130°C. Dodecylamine derivates are structural and thermally more fragile than those with octadecylamine. Under more drastic reaction conditions, 72h at 150°C, amine is segregated leading to almost pure inorganic nanotubes or fibers for octadecyl and dodecyl derivatives respectively. The products characterized by electron microscopy, X-ray diffraction, FT-IR and elemental analysis are constituted by the hydrogen titanat H2Ti3O7. Diffuse reflectance spectra reveal the products present typical size-dependent optical properties. The photoluminescence spectra are qualitatively similar to that of anatase dominated by the presence of traps located in the band gap. The electrochemical lithium intercalation and lithium diffusion coefficients of the products were studied by intermittent galvanostatic method and galvanostatic pulse relaxation technique respectively. Products were tested in a lithium cell using the nanocomposites as the active material of the positive electrode. The hybrid dodecylamine derivative shows a first cycle irreversible capacity of 219mAh/g, and a capacity of 113mAh/g after the 7th cycle which results improved in comparison with those reported for H2Ti3O7 electrodes, thus pointing to a protective effect of the amine. [Copyright &y& Elsevier]

Abstract: We report here the first in situ Raman microspectrometry study of the electrochemical lithium insertion and de-insertion reaction into crystalline sputtered Li x V2O5 thin films (0≤ x ≤0.94) in liquid electrolyte. We show that the orthorhombic Pmmn symmetry of the pristine material is kept upon lithium intercalation in the Li x V2O5 film (0≤ x ≤ 0.94). In fact, a subsequent and unexpected solid solution behaviour is evidenced, leading to the typical Raman fingerprint of the ɛ-LiV2O5 phase for the Li0.94V2O5 composition. After the charge, a complete recovery of the local structure is found, in good accord with the excellent electrochemical reversibility exhibited by these thin films. Such limited structural changes differ from that usually observed for the bulk material, which emphasizes the key role of the microstructure and morphology on the nature and magnitude of the structural rearrangements induced by the lithium insertion process. [Copyright &y& Elsevier]

Abstract: The effect of Ti incorporation on lithium intercalation capacity of V2O5 thin films prepared by spin coating using metalorganic (MO) and inorganic sol-gel (SG) precursors on indium tin oxide coated glass substrates have been investigated. Earlier studies show that V2O5–TiO2 oxide system has a higher cyclic stability than V2O5. However, there is controversy concerning the capacity of these mixed phases. We observe that upon incorporation of 5% Ti in MO films the lithium intercalation capacity decreases from 47 mC/cm2 to 27 mC/cm2, while for the SG films, the capacity increases from 14 mC/cm2 to 27 mC/cm2. We attribute this difference in the lithium intercalation capacity of the 5% Ti doped V2O5 films prepared by MO and SG precursors to the variation in the nonstoichiometry and the particle size. We find that it is essential to have a critical V:O ratio to achieve high intercalation capacity. Any deviations from this critical V:O ratio leads to a decrease in capacity and films having similar nonstoichiometry have similar values of intercalation capacity and diffusion coefficient. [Copyright &y& Elsevier]

Abstract: Nb2x V2−2x O5 (0≤ x ≤1) powders were prepared by a synthetic route based on the inorganic polymerization of alkoxy-choride precursors and characterized by a combination of X-ray diffraction, 51V and 93Nb NMR and Raman spectroscopy. Amorphous mesoporous thin films of similar compositions were successfully prepared by a modified Evaporation Induced Self Assembly method using polystyrene-b-polyethyleneoxide diblock copolymer as structuring agent. The electrochemical properties of the mesoporous films upon lithium insertion–deinsertion are investigated by cyclic voltammetry. This study highlights the advantages of such nanoarchitecture in terms of increased capacity to insert lithium. [Copyright &y& Elsevier]

Abstract: The sodium lithium titanate with composition Na2Li2Ti6O14 has been synthesized by a sol–gel method. Thermogravimetric analysis and differential thermal analysis (TG–DTA) of the thermal decomposition process of the precursor and X-ray diffraction (XRD) data indicate the crystallization of sodium lithium titanate has occurred at about 600°C. Electrochemical lithium insertion into Na2Li2Ti6O14 for lithium ion battery has been investigated for the first time. These results indicate the discharge and charge potential plateaus are about 1.3V. The initial discharge capacity is much higher than the charge capacity and irreversible capacity exists in the voltage window 1–3V. Subsequently, the discharge capacity decreases slowly, but the charge capacity increases slightly in the following cycles. After a few cycles, the specific capacity remains almost constant values and the sample exhibits the excellent retention of capacity on cycling. [Copyright &y& Elsevier]

Abstract: Graphite electrodes were modified by polyacrylic acid (PAA), polymethacrylic acid (PMA), and polyvinyl alcohol (PVA). Their electrochemical properties were examined in 1moldm−3 LiClO4 ethylene carbonate:dimethyl carbonate (EC:DMC) and propylene carbonate (PC) solutions as an anode of lithium ion batteries. Generally, lithium ions hardly intercalate into graphite in the PC electrolyte due to a decomposition of the PC electrolyte at ca. 0.8V vs. Li/Li+, and it results in the exfoliation of the graphene layers. However, the modified graphite electrodes with PAA, PMA, and PVA demonstrated the stable charge–discharge performance due to the reversible lithium intercalation not only in the EC:DMC but also in the PC electrolytes since the electrolyte decomposition and co-intercalation of solvent were successfully suppressed by the polymer modification. It is thought that these improvements were attributed to the interfacial function of the polymer layer on the graphite which interacted with the solvated lithium ions at the electrode interface. [Copyright &y& Elsevier]

Abstract: Layered metastable lithium manganese oxides, Li2/3[Ni1/3−x Mn2/3−y M x+y ]O2 (x = y =1/36 for M=Al, Co, and Fe and x =2/36, y =0 for M=Mg) were prepared by the ion exchange of Li for Na in P2-Na2/3[Ni1/3−x Mn2/3−y M x+y ]O2 precursors. The Al and Co doping produced the T#2 structure with the space group Cmca. On the other hand, the Fe and Mg doped samples had the O6 structure with space group R-3m. Electron diffraction revealed the 1:2 type ordering within the Ni1/3−x Mn2/3−y M x+y O2 slab. It was found that the stacking sequence and electrochemical performance of the Li cells containing T#2-Li2/3[Ni1/3Mn2/3]O2 were affected by the doping with small amounts of Al, Co, Fe, and Mg. The discharge capacity of the Al doped sample was around 200mAhg−1 in the voltage range between 2.0 and 4.7V at the current density of 14.4mAg−1 along with a good capacity retention. Moreover, for the Al and Co doped and undoped oxides, the irreversible phase transition of the T#2 into the O2 structure was observed during the initial lithium deintercalation. [Copyright &y& Elsevier]

Abstract: In this study, single crystal V3O7·H2O nanobelts were successfully synthesized using a simple hydrothermal route, in which templates or catalysts were absent. The synthesized V3O7·H2O nanobelts are highly crystalline and have lengths up to several tens of micrometers. The width and thickness of the nanobelts are found to be about 30–50 and 30nm, respectively. A lithium battery using V3O7·H2O nanobelts as the positive electrode exhibits a high initial discharge capacity of 409mAhg−1, corresponding to the formation of Li x V3O7·H2O (x =4.32). Such a high degree of electrochemical performance is attributed to the intrinsic properties of the single-crystalline V3O7·H2O nanobelts. [Copyright &y& Elsevier]

Abstract: In this study, ultra-thin nanobelts of Ag2V4O11/Ag were successfully synthesized. The synthesized ultra-thin nanobelts of Ag2V4O11/Ag are highly crystalline and the thickness is found to be about 5nm. A lithium battery using ultra-thin nanobelts of Ag2V4O11/Ag as the active materials of the positive electrode exhibits a high initial discharge capacity of 276mAhg−1, corresponding to the formation of Li x Ag2V4O11 (x =6). With increased cycling, the electrode made of ultra-thin nanobelts of Ag2V4O11/Ag tends to loose electrochemical activity due to Ag+ ions in the ultra-thin nanobelts of Ag2V4O11 were reduced and new phase was formed. [Copyright &y& Elsevier]

Abstract: Layered hydrated sodium titanate nanotubes are synthesized via a hydrothermal reaction in alkaline solution. The as-prepared nanotubes are calcined at different temperatures (300–600°C) in air. The microstructure of obtained samples is characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It is observed that the calcined products maintain their parent tubular morphologies below 500°C. After calcinations at 600°C, the hollow tubular morphology could completely be converted to the short solid nanorod morphology. In the meanwhile, the monoclinic sodium hexatitanate as a main phase is formed in nanorods, coexisted with sodium trititanate as a residual phase. The electrochemical lithium storage of obtained samples is studied by galvanostatic method and cyclic voltammetry. It is demonstrated that the nanotubes calcined at 500°C have relatively large reversible capacity, good reversibility and excellent high rate discharge capability. The lithium intercalation process is shown to have pseudocapacitive feature caused by their layered structure and open lithium insertion tunnels, which is in favor of the high rate charge/discharge capability of sodium titanate nanotubes. [Copyright &y& Elsevier]

Abstract: In situ atomic force microscopy (AFM) was used to study the morphology changes of a highly oriented pyrolytic graphite (HOPG) electrode modeling the negative electrode used in commercial lithium-ion batteries. During the charge (lithiation) process in 1M LiClO4 in ethylene carbonate:propylene carbonate (1:2) electrolyte we found that, degradation processes similar to the exfoliation of graphite also occur on basal planes. First a web-like structure of fine cracks develops which eventually results in local blister formation. [Copyright &y& Elsevier]