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The effects on the structure and electrical conduction behavior of strontium and zirconium doped LaInO3 was studied in this paper. XRD and Raman spectra both confirm that Sr and Zr cations are substitutionally introduced to the La- and In-sites to a certain limitation respectively. Cation vacancies may be the most likely point defects for ZrO2-doped LaInO3 perovskite oxide (LaIn0.9Zr0.1O3+δ), which leads to the decrease of oxygen-ion conductivity, while Sr doping (La0.9Sr0.1InO3−δ) produces oxygen vacancies and will greatly enhance the electrical conductivity of LaInO3. When Sr and Zr were co-doped with the same concentration (La0.9Sr0.1In0.9Zr0.1O3), the effects of Sr doping will be partially eliminated by Zr doping resulting in a relatively low electrical conductivity. When Sr-doping level increases further (La0.8Sr0.2In0.9Zr0.1O3−δ), its conduction behaves the same as that of La0.9Sr0.1InO3−δ since they are dominated by the same acceptor doping (10 mol%). Both La0.8Sr0.2In0.9Zr0.1O3−δ and La0.9Sr0.1InO3−δ show three different conduction regions, that is, p-type at high PO2, n-type at low PO2 and PO2-independent conduction at intermediate oxygen partial pressure while only p-type conduction appears for La0.9Sr0.1In0.9Zr0.1O3 at high PO2, and LaIn0.9Zr0.1O3+δ shows an entirely different conduction behavior in the measured oxygen partial pressures.

Glassy material Li2O·4MnO1+x·4B2O3 (0

Interactions between propylene carbonate (PC) and lithium bis(trifluoromethane sulfone imide) [LiTFSI, LiN(CF3SO2)(2)] were studied by Fourier transform (FT) Raman and IR spectroscopy. It was found that PC interacts with the Li+ ions and the TFSI- anions through its skeletal oxygen atoms, leading to solvent-separated ion pairs and contact ion pairs in the solution by way of the nitrogen atoms on the anion. Copyright (C) 2001 John Wiley & Sons, Ltd.

New alkali salts based on (fluorosulfonyl)(pentafluoroethanesulfonyl)imide {[(FSO(2))(C(2)F(5)SO(2))N](-), FPFSI(-)} anion are introduced, together with a new effective preparation of C(2)F(5)SO(2)NH(2) and H[FPFSI]. The former amide was prepared by amination of lithium pentafluoroethanesulfinate (C(2)F(5)SO(2)Li) with NH(2)OSO(3)H, which was converted to the H[FPFSI] by sequential chlorosulfonation with SOCl(2)/CISO(3)H, and fluorination by SbF(3).

Li–Ag alloys and solid electrolyte interface films are produced by electrochemical reactions occurring on the surface of an Ag plate electrode in a lithium battery. The surface enhanced resonance Raman spectrum of rhodamine 6G (Rh 6G) and the surface enhanced Raman spectrum of the solid electrolyte interface film on the surface of Li–Ag alloys were observed for the first time. The surface enhanced Raman spectra varied according to the surface roughness and the concentration of lithium in the Li–Ag alloys.

The crystal structure and morphology of nanosized Si particles and wires after Li-insertion/extraction electrochemically have been studied by ex-situ XRD, Raman spectroscopy and electronic microscopy. It is confirmed that the insertion of lithium ions at room temperature destroys the crystal structure of Si gradually and leads to the formation of metastable amorphous Li–Si alloy. Furthermore, local ordered structure of Si can be restored after the partial extraction of lithium ions, which indicates the extraction of lithium ions promoting the recrystallization of amorphous Li-inserted Si. It was also observed that nanosized Si particles and wires were merged together after the insertion/extraction of lithium ions.

Li/Ag and Li/Al electrochemical cells composed of smooth Ag or Al electrode sheets, respectively, and matched with nonaqueous electrolytes were assembled and discharged. Discharged Ag electrodes were investigated using micro-Raman spectromety. Raman bands attributed to the components of the passivating film on the surface of the discharged Ag electrode, such as Li2CO3 and other species, were observed. No characteristic bands from discharged Al electrodes were present in the Raman spectra. This indicates that the Raman signals for the passivating layer are surface-enhanced by discharged Ag electrodes. The formation of a nanometer-scale rough surface caused by a Li−Ag alloy reaction during the discharging process is an important factor in the enhancement. It was also shown that the passivating films formed in various electrolytes could be distinguished by SERS.

The effects of dopants on the electrical conductivity of the perovskite-type oxide LaInO3 have been investigated. Replacement of La by Sr is the most effective way to enhance the conductivity of LaInO3, whereas Ca substitution for In is rather difficult due to the large difference in the ion radii. The optimum composition is La0.9Sr0.1InO3-delta whose maximum conductivity is 7.6 X 10(-3) S cm(-1) at 900 degrees C. The electrical conductivity of La0.9Sr0.1InO3-delta has been measured over a wide range of oxygen partial pressure from pO(2) =1 to 10(-25) atm. P-type and n-type behavior at high and low oxygen partial pressure have been observed, respectively, while at intermediate oxygen partial pressures, the electrical conductivity changes only slightly with the oxygen partial pressure. The concept of a single layer solid oxide fuel cell based on a La0.9Sr0.1InO3-delta ceramic pellet has been tested. A maximum power density of 3 mW cm(-2) at 800 degrees C was achieved when dilute H-2 and air were used as fuel and oxidizing agent, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.

It has been found that the electrical conduction behavior of La0.9Sr0.1InO3−δ varies with oxygen partial pressure. P-type and n-type conduction at high and low oxygen partial pressure have been observed respectively. While at intermediate oxygen partial pressures, the electrical conductivity changes slightly with the oxygen partial pressure. Thus, La0.9Sr0.1InO3−δ may be a possible material for making single layer solid oxide fuel cell (SLFC). The concept of SLFC has been tested using a piece of thick ceramic pellet of La0.9Sr0.1InO3−δ. The maximum current density and power density is 12 mA/cm2 and 3 mW/cm2 at 800 °C when dilute H2 and air were used as fuel and oxidizing agent, respectively. The phase stability of La0.9Sr0.1InO3−δ has been studied by Raman spectra and XRD. It is confirmed that secondary phase may appear in La0.9Sr0.1InO3−δ after long term testing in low oxygen partial pressure, and finally it may be decomposed into La2O3 and metal Indium. Much attention should be paid to stabilize La0.9Sr0.1InO3−δ and to improve the performance of SLFC.

0.5LiMnO2-0.5B2O3 glass has been prepared by quenching a melt of LiNO3, MnO2 and B2O3 at 1100°C to room temperature in air. The crystallization mechanism of this kind of glass was investigated by differential thermal analysis (DTA) and powder X-ray diffraction (XRD). It is shown that the substances crystallized from powder and bulk samples are different because manganese with lower valence in powder sample can be further oxidized by the oxygen penetrated through the large surface of powder sample. For a powder sample the glass transition endothermic peak in the DTA curve is overlapped by an exothermic reaction attributed to the oxidization of Manganese. LiMn2O4 can not be crystallized directly from the glass matrix but can be formed on the surface of glass particles by effect of oxygen in air near the glass transition temperature.

A new reductive co-precipitation route to synthesize a pure phase nanosized β-SnSb alloy in alcohol solution at low temperature is reported. The morphology and particle size of the β-SnSb alloy are influenced by temperature, stirring and the solvent. The nanosized β-SnSb alloy prepared by this method shows good electrochemical performance as an anode material for lithium ion batteries. The β-SnSb alloy transforms gradually into multiphase Li3Sb and LixSn with increased insertion of lithium ions. After extraction of the lithium ions, the original crystal structure of β-SnSb is restored, even after many cycles.

Fine powders of tin oxide doped with traces of silicon in combination with highly dispersed amorphous silicon oxide have been synthesized by an advanced ultrasonic spray method. The mixtures have been analyzed by XRD and IR. The electrochemical results showed that addition of silicon decreases the tin oxidation state, and, hence, reduces the irreversible capacity during the first discharge/charge cycle. SiO2 and Li2SiO3 appeared during the first discharging as confirmed by IR spectroscopy. Furthermore, a reversible capacity of 900 mA h/g to 950 mA h/'g for these composites has been found, which is even higher than the theoretical value (783 mA h/g according to the Li4.4Sn). The chemical diffusion coefficients of lithium in the Li-Sn alloy phases formed (Li0.4Sn, LiSn, Li3Sn7, Li3.5Sn and Li4.4Sn) have been measured by galvanostatic intermittent titration technique (GITT). Below a Li content corresponding to Li3Sn7, a reduced voltage polarization as well as an increased lithium chemical diffusion coefficient were observed. This improved performance is due to an enhanced interfacial diffusion, caused by highly dispersed inert second phases, i.e., SiO2 and LiSi2O3. (C) 1999 Elsevier Science S.A. All rights reserved.

The mechanisms for the high capacity of lithium insertion in low-temperature pyrolytic carbons are not fully understood though several models have been proposed. None of the existing models considers the reversible crystalline structural changes within a graphene layer in the discharge–charge processes. In this report, low-temperature pyrolytic phenolic resin and lithium ion cells made of it are characterized by Raman spectroscopy, XRD and elemental analysis as well as discharge/charge measurements. The linear relation is confirmed between the specific capacity of the low-temperature pyrolytic carbon and its H/C atomic ratio after eliminating the influence of the crystallite size to the capacity. It is found that the evolution of the Raman spectrum of the pyrolytic carbon electrode upon discharge and charge is quite different from that of the other forms of carbonaceous electrodes. Based on the characteristic Raman spectra and the discharge–charge curves of the carbon electrode, a breaking-recovery model of the weak C⋯H bond is suggested for the lithium insertion/extraction processes in the low-temperature pyrolytic carbon electrodes.

A series of composite SnO materials were prepared by mixing SnO powder with reducing agents and heating at different temperatures for different periods under argon atmosphere. It was found that alpha-SnO with its tetragonal structure could transform into the beta-Sn phase or orthorhombic SnO depending on treatment conditions. The electrochemical behaviors of these materials used as an anode active material in lithium rechargeable batteries was investigated. It was found that excessive amounts of reducing agents, especially in the case of carbon black, may provide a good dispersion environment for SnO which is similar to the case of amorphous tin composite oxides (TCO). The presence of beta-Sn or orthorhombic SnO is not beneficial to the cycling performance, although a large ratio of beta-sn in the starting anode material can decrease the capacity loss during the first cycle. Superfine SnO material was also prepared by decomposing SnC2O4 which was synthesized by a sol-gel method. Its cyclic performance was improved significantly. (C) 1999 Elsevier Science S.A. All rights reserved.

Nano-SnO and normal SnO anodes for lithium rechargeable batteries have been investigated by electrochemical impedance spectroscopy (EIS). Three types of equivalent circuits have been used to fit the spectra at different discharge states. The variations of impedance spectra, charge-transfer resistance and double layer capacitance have been discussed. The electrochemical reaction mechanism of SnO anode for lithium ion batteries can be deduced as follows: a passivating film forms on the surface of SnO particles firstly, then Li+ ions pass through the surface film and react with SnO to produce amorphous Li2O and to form fine grains of Li–Sn alloys in the core region underneath the passivating film.

A two-step reaction mechanism of oxide materials as anodes in rechargeable lithium batteries was found by comparing discharge–charge curves and cyclic voltammograms of eight oxides. It was also proved by experiments of ex-situ XRD of Sb2O3 anode at discharged state. HRTEM images of nanometre SnO at deep discharged state confirmed the two-step reaction mechanism and showed the typical microstructure character of reaction products: the particle was composed of a large amount of nanosized Li–Sn alloy which dispersed in the Li2O matrix. Furthermore, it was found that the electrochemical properties of SnO anodes were influenced by the particle size of SnO.

Raman, infrared (IR), fluorescence, X-ray photoelectron (XPS), and nuclear magnetic resonance (NMR) spectra of various combinations of the components of the polyacrylonitrile (PAN)-based electrolytes have been studied, it is found that the so-called composite- or mixed-phase polymer electrolytes are not simple mixtures of electrolytic salt, plasticizer and polymer; instead there are strong interactions between each two of the components of the electrolytes and strong competitions between the plasticizer and PAN to associate with the Li+ ions though different systems may show different interaction characteristics. By analyzing the important roles of the plasticizer, a possible mechanism of the ion transport in the PAN-based polymer electrolyte is proposed. (C) 1999 Elsevier Science BN. All rights reserved.

The phase transition of LiNiO2 has been studied by using impedance spectroscopy, DTA, and X-ray diffraction methods. At 720°C the hexagonal phase changes in air to the cubic phase. The phase transition process is rather slow and partially reversible. A peculiar conductivity behavior was observed. From 324°C the conductivity deviates from Arrhenius behavior and is temperature-invariant until 613°C. Subsequently, it decreases rapidly with increase of the temperature. This phenomenon is related to the occupation of Ni2+ in Li+ positions. The optimal sintering temperature for LiNiO2 is suggested to be 700°C.

Lithium/carbon (Li/C) cells have been assembled with phenolic resin, pyrolyzed at 650°C for 2 h, as the working electrodes. By measuring the Raman spectra of the carbon electrodes discharged and charged to various equilibrium voltages and the discharge/charge curves of the Li/C cell, it is found that the intensity of the G-band of the discharged/charged pyrolytic carbon electrode in the Raman spectrum decreases to zero with decreasing discharge voltage and then gradually recovers with increasing charge voltage. However, the intensity of the D-band remains unchanged during the discharge/charge processes. This spectroscopic behavior is quite different from that of the other forms of carbonaceous electrodes. Based on the analysis of the characteristic Raman spectra and the discharge/charge curves of the pyrolytic carbon electrodes, a breaking-recovering model of the weak. C· · ·H bond within a graphene layer is suggested for the lithium insertion and extraction processes in the low-temperature pyrolytic carbon electrodes.

The electrochemical properties of microwave-synthesized LiCoO2 have been investigated by galvanostatic intermittent titration technique (GITT), impedance spectroscopic analysis (EIS) and charge/discharge capacity measurement. The results of EIS indicate that the cathode composed of microwave-synthesized LiCoO2 has large cathode/electrolyte interface area due to its fine powder size, which leads to good cyclability and capability to withstand large current density. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

Dispersion strengthened (DS) Cu-Al25 alloy containing small Al2O3 particles (similar to 4 nm in diameter) was irradiated by 300 keV Cu+ ion to doses of 10 dpa and 30 dpa with a displacement rate of 3.7 x 10(-2) dpa/s at room temperature, which simulates the effects of high energy primary knock-on atoms (PKA) produced by 14 MeV neutrons. Microstructural evolution was investigated by transmission electron microscopy (TEM). Selected area diffraction (SAD) was used to study the phase stability of alumina under irradiation. The defect cluster structure formed by irradiation was investigated by dynamic two-beam techniques. Small particles of Al2O3 were dissolved under ion irradiation with increasing fluences. A large number of small Frank vacancy and interstitial dislocation loops (similar to 5 nm in diameter) with different Burgers vectors of a/3[1 1 1] are produced by ion irradiation. At the region adjacent to the irradiation surface the number of vacancy loops was greater than that of interstitial ones. This result is in good agreement with the computer simulation results. (C) 1998 Elsevier Science B.V. All rights reserved.

Five natural graphites with different rhombohedral phase (3R phase) content have been investigated as anode materials for rechargeable lithium-ion batteries. The reversible capacity varies from 250 mA h/g to 350 mA h/g for the same intercalation conditions depending on the content of the 3R-phase. With increasing rhombohedral phase in the graphite, the intercalation capacity will be high. A peak at about 10 mV in the cyclic voltammograms (CV) of a sample with a large 3R-phase content is caused by lithium ions occupying boundaries between the rhombohedral (3R) phase and the hexagonal (2H) phase and is responsible for a capacity exceeding the theoretical value.

Raman spectra of highly oriented pyrolytic graphite (HOPG), natural polycrystalline graphite (PCG), high pressure graphite (HPG), and low-temperature pyrolyzed polyfurfuryl alcohol (PFA) have been measured. Comparing the Raman spectra of each sample illuminated with laser beams of 488.0 nm and 1064.0 nm wavelengths, respectively, unambiguous dispersion effects have been observed for the D′-line in HOPG and in other forms of PCG as well as for their D lines. Comparisons of the intensity ratios of the D′ line to the D line (ID′/ID) of HOPG and polycrystalline indicate that the dispersion effects of the D′ line and the D line may have the same physical origin. In addition, it has also been observed that the G-line position of low-temperature pyrolyzed PFA is sensitive to the excitation wavelength while that of HOPG, PCG, and HPG is not. This phenomenon is attributed to the nanometer size of the microcrystalline graphites by analyzing the factors that may induce such a dispersion effect.

The structural evolution of SnO2 fine powder prepared by a sol-gel method upon heat-treatment was investigated by using x-ray diffraction. Electrochemical measurements showed that the reversible capacity of lithium ion reaction with the SnO2 electrode could be as high as 600 mAh/g. The mechanism of lithium ion reaction was studied by ex situ x-ray diffraction and Raman spectroscopy. Two processes were revealed: a substitution reaction, in which SnO2 is reduced and Sn is formed, followed by LiySn alloy formation.

Polyfurfuryl alcohol (PFA) is pyrolyzed at 600 °C for different lengths of heat-treatment (HT) time (0–50 h) and at different pyrolytic temperatures (600–850 °C) for 4 h. Analysis by Raman spectroscopy shows that the crystallite size of PFA pyrolyzed at 600 °C decreases with increasing HT time. This suggestion is supported by the electrical conductivity measurements on PFA samples pyrolyzed at different HT temperatures and at 600 °C for different HT times. A trend of transition from semiconductive to metallic properties is suggested for the samples prepared above 850 °C.

The stability of polytetrafluorethylene (PTFE) and polyvinylidene fluoride (PVDF) used as the anode binders in lithium-ion batteries was studied by electrochemical and X-ray photospectroscopy (XPS) measurements. The characteristic discharge/charge curves for PTFE and PVDF were obtained. It is shown that the behavior of PTFE and PVDF exhibits much discrepancy when they are attacked by high active lithium ion in electrochemical cells. PTFE reacts with lithium easily and decomposes during the first discharge process, which is indicated by a long plateau appearing around 1.2 V in the first discharge curve of Li/Ni(PTFE) cell. XPS results show that PTFE decomposes after one discharge/charge cycle. PVDF is rather stable due to a possible surface passivation process.

The Raman and infrared spectra of the systems of plasticizer/LiClO4 and plasticizer/polyacrylonitrile (PAN)/LiClO4 have been recorded, where the plasticizer includes dimethylformamide (DMF) and propylene carbonate (PC). By comparing the spectra. it is found that the association of Li+ ion is more competitive with DMF than with PC in the Liquid or gel electrolytes. Moreover the addition of PAN into DMF/LiClO4 solution has less influence on the Li+-solvent association than into PC/LiClO4 solution. Although a strong interaction has been observed between Li+ ions and PAN in PC/LiClO4/PAN electrolytes, no similar interaction is observed between Li+ ion and PAN in DMF/PAN/LiClO4 system. However. after the plasticizer is removed from the gel electrolytes, apparent interaction is observed between Li ion and PAN. These phenomena lead to a conclusion that there is a competition between the plasticizer and the polymer for association with the Li+ ions in the PAN based electrolytes. In addition, it is found that the multiple ion aggregates are formed without the appearance of the usual ''solvent-shared ion aggregates'' in the plasticizer-free electrolyte, which suggests that the Li+ ions may move both in the gel state and with the segmental chain of PAN while the ClO4- anion migrates mainly in the gel state in a practical PAN-based electrolyte.

The Raman and infrared spectra of dimethylformamide (DMF)/polyacrylonitrile (PAN)/lithium perchlorate (LiClO4) have been measured and analyzed. It is found that the interaction between DMF and PAN is not strong, probably resulting from the dipole interaction between the O=C-N group of DMF and the nitrile group of PAN. Compared with the Raman spectra of DMF/LiClO4 system, it seems that the addition of PAN promotes the ion association between Li+ ions and the plasticizer molecules. However, in spite of the wide range of molar ratios of DMF/PAN/LiClO4 studied, no ion association was observed between the nitrile group of PAN and the Li+ ions in the DMF/PAN/LiClO4 system. This indicates that the details of the transport mechanism of Li+ ions in the electrolyte may be related to the plasticizer.

As part of the systematic research on the interactions between the components of the polyacrylonitrile-based electrolytes (plasticizer-lithium salt-polymer), the Raman and IR spectra of pure dimethylsulfoxide (DMSO) and DMSO containing different molar ratios of LiClO4 have been studied. By analyzing the Raman and IR spectra of the SO stretching band, it is found that the introduction of LiClO4 to pure DMSO leads to the dissociation of the cyclic dimers. Li+-DMSO associates are formed through the interaction between Li+ and the SO group of DMSO. The spectral changes of the SO binding bands and the CH stretching bands indicate that the interaction between the Li+ ion and the molecule not only breaks down the self-association of the solvent, but also, by way of the induction effect, perturbs the electronic nebula around the CH bond. It seems that the effect of the ClO4− anion on the molecules is too weak to be observed by the vibrational spectroscopy.

Room-temperature sodium-ion batteries have shown great promise in large-scale energy storage applications for renewable energy and smart grid because of the abundant sodium resources and low cost. Although many interesting positive electrode materials with acceptable performance have been proposed, suitable negative electrode materials have not been identified and their development is quite challenging. Here we introduce a layered material, P2-Na0.66[Li0.22Ti0.78]O2, as the negative electrode, which exhibits only ~0.77% volume change during sodium insertion/extraction. The zero-strain characteristics ensure a potentially long cycle life. The electrode material also exhibits an average storage voltage of 0.75 V, a practical usable capacity of ca. 100 mAh g(-1), and an apparent Na(+) diffusion coefficient of 1 × 10(-10) cm(-2) s(-1) as well as the best cyclability for a negative electrode material in a half-cell reported to date. This contribution demonstrates that P2-Na0.66[Li0.22Ti0.78]O2 is a promising negative electrode material for the development of rechargeable long-life sodium-ion batteries.

International audience; The high voltage spinel LiNi0.5Mn1.5O 4-δ films were obtained by pulsed laser deposition. The effects of oxygen deficiency, annealing treatment, and film thickness on microstructure, morphology and electrochemical properties were investigated. We showed that tuning the oxygen pressure and annealing treatment allows modifying the oxygen film stoichiometry. Trying to determine the oxygen stoichiometry in thin films, a series of oxygen-deficient spinel "LiNi0.5Mn 1.5O4-δ" powder samples by quench steps from different temperatures were prepared. It is demonstrated that powders and thin films presenting similar cell parameters, namely related to the oxygen stoichiometry, show similar electrochemical profiles. Meanwhile, the compatibility of electrolyte with substrate and the stability of the target were also investigated.

The development of suitable anode materials for room-temperature sodium-ion batteries remains a challenging issue. Sun et al. show that the well-known zero-strain Li4Ti5O12 anode for lithium storage is capable of reversibly hosting sodium ions via a three-phase storage mechanism.

A new designed reaction chamber with new relative distribution of filament and substrates has been adopted in order to increase the deposition area of diamond films and thus increase the deposition efficiency in conventional hot filament chemical vapor deposition (HFCVD) systems. The relatively small reaction chamber was cuboid shaped (50 x 25 x 25 mm(3)) and composed of molybdenum wafers. It was established in the vacuum chamber. A tungsten filament was hung up vertically in the center of the small chamber and parallel to the gas flow path. At the four inner sides of the reaction chamber, four Si(100) substrates (30 x 10 x 0.5 mm(3)) were installed to grow diamond films. The deposition results indicate that uniform diamond films can be obtained on the four substrates, and the film growth rate is the same at both ends of the substrates. The diamond film growth rate was about 1-2 mu m/h, which is similar to those of the conventional HFCVD method. Thus, the deposition area and efficiency can be increased four times in the case without the filament number, gas how rate, and power consumption.

The rate-determining step of the intercalation and deintercalation process of lithium ions in LixNiO2 cathodes was studied by electrochemical impedance spectroscopic (EIS) analysis. EISs of the electrode process are composed of two semicircles. The higher frequency semicircle is related to the charge transfer resistance (Rct) and the double layer capacitance (Cdl), while the lower frequency semicircle results from ion incorporation impedance (Rlattice) and space charge capacitance (Csc). The assignment of the latter capacitance is discussed. It is found that Rlattice is 1000 times larger than Rct. Accordingly, in most cases the ion incorporation into the lattice dominates the kinetic behavior. But for the ideal hexagonal phase, in the deintercalated state the Warburg impedance becomes important. As a result, the ion diffusion in the lattice is the rate-determining step.

Replacing organic liquid electrolyte with inorganic solid electrolytes (SE) can potentially address the inherent safety problems in conventional rechargeable batteries. However, solid-state batteries (SSBs) have been plagued by the relatively low ionic conductivity of SEs and large charge-transfer resistance between electrode and SE. Here, a new design strategy is reported for improving the ionic conductivity of SE by self-forming a composite material. An optimized Na+ ion conducting composite electrolyte derived from the Na1+ n Zr2Si n P3− n O12 NASICON (Na Super Ionic Conductor) structure is successfully synthesized, yielding ultrahigh ionic conductivity of 3.4 mS cm−1 at 25 °C and 14 mS cm−1 at 80 °C. On the other hand, in order to enhance the charge-transfer rate at the electrode/electrolyte interface, an interface modification strategy is demonstrated by utilization of a small amount of nonflammable and nonvolatile ionic liquid (IL) at the cathode side in SSBs. The IL acts as a wetting agent, enabling a favorable interface kinetic in SSBs. The Na3V2(PO4)3/IL/SE/Na SSB exhibits excellent cycle performance and rate capability. A specific capacity of ≈90 mA h g−1 is maintained after 10 000 cycles without capacity decay under 10 C rate at room temperature. This provides a new perspective to design fast ion conductors and fabricate long life SSBs.

Lithium (Li) metal is an ideal anode material for rechargeable Li batteries, due to its high theoretical specific capacity (3860 mAh/g), low density (0.534 g/cm3), and low negative electrochemical potential (−3.040 V vs. standard hydrogen electrode). In this work, the concentrated electrolytes with dual salts, composed of Li[N(SO2F)2] (LiFSI) and Li[N(SO2CF3)2] (LiTFSI) were studied. In this dual-salt system, the capacity retention can even be maintained at 95.7% after 100 cycles in Li|LiFePO4 cells. A Li|Li cell can be cycled at 0.5 mA/cm2 for more than 600 h, and a Li|Cu cell can be cycled at 0.5 mA/cm2 for more than 200 cycles with a high average Coulombi efficiency of 99%. These results show that the concentrated dual-salt electrolytes exhibit superior electrochemical performance and would be a promising candidate for application in rechargeable Li batteries.

Sodium-ion batteries (SIBs) have attracted more and more attention for scalable electrical energy storage due to the abundance and wide distribution of Na resources. However, the anode still remains a great challenge for the application of SIBs. Here the production of uniform hard carbon microtubes (HCTs) made from natural cotton through one simple carbonization process and their application as an anode are reported. The study shows that the electrochemical performance of the HCTs is seriously affected by the carbonization temperature due to the difference in their microstructure and heteroatomic content. The HCTs carbonized at 1300 °C deliver the highest reversible capacity of 315 mAh g−1 and good rate capability due to their unique tubular structure. This contribution not only provides a new approach for the preparation of hard carbon materials with unique tubular microstructure using natural inspiration, but it also deepens the fundamental understanding of the sodium storage mechanism.

The electrochemical properties of Li x Mn 2 O 4 with 0.5≤ x ≤2.5 as the lithium content in the starting materials, have been studied. A novel wet-chemical route has been developed. The lithium chemical diffusion coefficient in Li x Mn 2 O 4 as synthesized by this wet-chemical technique is at least 10 times higher than that of LiMn 2 O 4 obtained by solid state reaction. In the observed two-phase regions near x = 0.75 and 1.75 diffusion enhancement ascribed to interfacial diffusion is observed. The results of cyclic voltammetry and impedance analysis provide additional evidence for this hypothesis.

Room-temperature sodium-ion batteries attract increasing attention for large-scale energy storage applications in renewable energy and smart grid. However, the development of suitable anode materials remains a challenging issue. Here we demonstrate that the spinel Li4Ti5O12, well-known as a 'zero-strain' anode for lithium-ion batteries, can also store sodium, displaying an average storage voltage of 0.91 V. With an appropriate binder, the Li4Ti5O12 electrode delivers a reversible capacity of 155 mAh g(-1) and presents the best cyclability among all reported oxide-based anode materials. Density functional theory calculations predict a three-phase separation mechanism, 2Li4Ti5O12+6Na(+)+6e(-)↔Li7Ti5O12+Na6LiTi5O12, which has been confirmed through in situ synchrotron X-ray diffraction and advanced scanning transmission electron microscope imaging techniques. The three-phase separation reaction has never been seen in any insertion electrode materials for lithium- or sodium-ion batteries. Furthermore, interfacial structure is clearly resolved at an atomic scale in electrochemically sodiated Li4Ti5O12 for the first time via the advanced electron microscopy.

The storage characteristics of the battery, Li/PEOPCLiClO 4 /Li 1+ x V 3 O 8 composite, has been studied by intermittent charge/ discharge and impedance analysis during a storage period of 322 days. The dc resistance and IR drop increase but capacity and charge efficiency of the battery decrease with storage time. Upon storage a second arc appears in the impedance spectrum corresponding to both anode/electrolyte and cathode/electrolyte interface behavior. These results may be attributed to the formation of the anode passivation and/or dendrite growth of lithium.

The sensing behaviour of three kinds of Bi-based superconductor film, differing in microstructure has been studied. The films comprise Bi 2 Sr 2 CaCu 2 O 8+ x (BSCCO) with “open neck” contacts between grains, Bi 2 Sr 2 CuO 6+ x (BSCO) prepared by electronic beam evaporation and Bi 2 Sr 2 CaCu 2 O 8+ x with “Schottky-barrier-limited” conductance. The sensitivity and selectivity to N O and NO 2 gases against CO and CO 2 have been investigated. The flow rate dependence of the NO x sensitivity has been measured. The sensing behaviour of the third film to NO has been measured with both air and Ar as carrier gas. NO behaves as a reductant in air on the surfaces of Bi 2 Sr 2 CaCu 2 O 8+ x and Bi 2 Sr 2 CuO 6+ x . NO 2 is neither reductant nor oxidant unde r the same conditions. A qualitative sensing mechanism for NO x on Bi 2 SrCaCu 2 O 8+ x and Bi 2 Sr 2 CuO 6+ x is proposed.

A patterned silicon electrode as the anode of lithium ion batteries is fabricated by microfabrication technology. An ultrathin alumina layer is coated on the patterned electrode by atomic layer deposition (ALD). This results in obviously enhanced coulombic efficiency and cycling performance. [GRAPHICS] .

All-solid-state lithium microbatteries were fabricated using the ceramic superconductor YBa 2 Cu 3 O 7−δ as cathode, and a PAN-based polymer as electrolyte. The employed cathode films had a thickness of about 10μm. The charge and discharge current can reach values up to 100 μA/cm 2 at room temperature. The performance of the microbatteries was evaluated by cyclic voltammetry and a.c. impedance spectroscopy measurements. The batteries exhibit a good cycle life, capacity and efficiency.

The structural evolution of SnO2 fine powder prepared by a sol-gel method upon heat-treatment was investigated by using x-ray diffraction. Electrochemical measurements showed that the reversible capacity of lithium ion reaction with the SnO2 electrode could be as high as 600 mAh/g. The mechanism of lithium ion reaction was studied by ex situ x-ray diffraction and Raman spectroscopy. Two processes were revealed: a substitution reaction, in which SnO2 is reduced and Sn is formed, followed by LiySn alloy formation.

A nano-Si composite material (NSCM) has been prepared by mixing nanometer-scale (78 nm) pure Si powder and carbon black. The electrochemical performance of NSCM anodes for lithium rechargeable batteries exhibited an extremely high reversible capacity, over 1700 mAh/g Si, at the tenth cycle. The voltage profile is flat and smooth ranged from 0.4 to 0.0 V vs. Li/Li+. In addition, the cyclic performance is good even at larger current densities. Consequently, NSCM can be used as a novel high capacity anode material for lithium-ion batteries. (C) 1999 The Electrochemical Society. S1099-0062(98)10-053-6. All rights reserved.

Nanosized SnSb alloy particles were pinned on the surface of micrometer-sized hard carbon spherules by a coprecipitation method in glycol solution at low temperature. Thanks to the small alloy particle size, good dispersion, and tight pinning of the alloy particles on the surface of carbon, in addition to the fact that both the alloy and the carbon are active for Li storage, the composite materials as prepared show much improved electrochemical performances as anode materials for lithium ion batteries compared with alloy and carbon alone. Such a special structure effectively hinders the aggregation of nanosized alloy particles, which are the main difficulties in the application of nanoscale alloy-based anode materials for Li ion batteries.

The features related to nano-alloy anode for Li ion batteries are summarized in this paper mainly based on our recent studies on nano-SnSb. Electrochemical agglomeration, irreversible trapping of inserted ions by host lattice, and unstable solid electrolyte interphase (SEI) film are highlighted. A strategy that pinning nano-alloy particles on the surface of micrometer-sized carbon particles is introduced, in which all components are active for Li storage.

In order to address power and energy demands of mobile electronics and electric cars, Li-ion technology is urgently being optimized by using alternative materials. This article presents a review of our recent progress dedicated to the anode and cathode materials that have the potential to fulfil the crucial factors of cost, safety, lifetime, durability, power density, and energy density. Nanostructured inorganic compounds have been extensively investigated. Size effects revealed in the storage of lithium through micropores (hard carbon spheres), alloys (Si, SnSb), and conversion reactions (Cr(2)O(3), MnO) are studied. The formation of nano/micro core-shell, dispersed composite, and surface pinning structures can improve their cycling performance. Surface coating on LiCoO(2) and LiMn(2)O(4) was found to be an effective way to enhance their thermal and chemical stability and the mechanisms are discussed. Theoretical simulations and experiments on LiFePO(4) reveal that alkali metal ions and nitrogen doping into the LiFePO(4) lattice are possible approaches to increase its electronic conductivity and does not block transport of lithium ion along the 1D channel.