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A “5V‐class” all‐solid‐state lithium battery (Li/Li3.2PO3.8N0.2/LiCr0.05Ni0.45Mn1.5O4‐δ) demonstrates an improved rate capability when its electrolyte/cathode interface is modified by dielectric BaTiO3 nanoparticles. Such “dielectric modification” is supposed to be able to resolve a Li+‐deficient layer at the interface, which has limited the charge‐transfer reactions rates. [ABSTRACT FROM AUTHOR]

Abstract: We report on the structure and lithium ion transport properties of Li1.5Al0.5Ge1.5(PO4)3 (LAGP). This material is commercially available and is prepared as amorphous powders via a flame spray technique called Flash Creation Method (FCM). We crystallize and sinter the amorphous powders at different temperatures in order to alter grain size and grain boundary properties. The structure is then characterized by means of powder X-ray diffraction, atomic force microscopy, scanning electron microscopy and transmission electron microscopy with energy dispersive X-ray spectroscopy. AC impedance spectroscopy is used to study lithium ion transport. A maximum total conductivity of 2×10−4 Scm−1 at room temperature is found for a sample sintered at 750°C for 2h. In order to distinguish between grain and grain boundary contributions to the impedance spectra, equivalent circuit fits are carried out. The results are analysed in the framework of the classical brick layer model and of a finite-element approach taking into account non-ideal grain contacts. Our experimental results for the grain and grain boundary resistances are in good agreement with the predications of the finite-element approach. [Copyright &y& Elsevier]

Abstract: A novel all-solid-state thin-film-type rechargeable lithium-ion battery employing in situ prepared both positive and negative electrode materials is proposed. A lithium-ion conducting solid electrolyte sheet of Li2O–Al2O3–TiO2–P2O5-based glass–ceramic manufactured by OHARA Inc. (OHARA sheet) was used as the solid electrolyte, which was sandwiched by Cu and Mn metal films. The Cu/OHARA sheet/Mn layer became an all-solid-state lithium-ion battery after applying d.c. 16V to the layer, and the resultant battery operated at 0.3–0.8V with reversible capacity of 0.45μAhcm−2. High voltage battery was successfully prepared by applying the d.c. high voltage to a five-series of Cu/OHARA sheet/Mn layer, resulting in all-solid-state battery operating at 1.5–4.0V. The proposed fabrication process will become a new technology to develop advanced all-solid-state rechargeable lithium-ion batteries. [Copyright &y& Elsevier]

Abstract: A new kind of all-solid-state thin-film-type lithium-ion battery was fabricated by applying a D.C. high voltage. Application of the D.C. high voltage to a layer of Cu/Li2O–Al2O3–TiO2–P2O5-based glass ceramics sheet/amorphous Li–Mn–O/Pt, where Cu side was connected to cathode and Pt side to anode, permitted an “in situ formed” negative electrode material at the Cu/glass ceramics sheet interface. This negative electrode material was reductive decomposition material of the glass ceramics formed at the glass ceramics/Cu interface. The negative electrode material was irreversibly formed and then some of reaction current was required to be prepared. It was suggested that application of D.C. high voltage to the layer induced the oxidation reaction of oxygen ions at the positive electrode side around the amorphous Li–Mn–O/glass ceramics interface, which was consumed to prepare the negative electrode material. The resultant all-solid-state thin-film-type lithium-ion battery repeated stable charge–discharge reaction at 1.4V. [Copyright &y& Elsevier]

Abstract: Lithium iron phosphate (LiFePO4) thin film electrodes were prepared by pulsed laser deposition (PLD). The thin films were annealed at various temperatures under argon gas flow and the influence of annealing temperature on their electrochemical performance was studied. The thin films annealed at 773 and 873K exhibited a couple of redox peaks at 3.4V (versus Li/Li+) that are characteristics of the electrochemical lithium insertion/extraction of LiFePO4. Atomic force microscopy (AFM) observation revealed that the film annealed at 773K (773K-film) consisted of small grains with 50nm in thickness, and the grain size increased with an increase of annealing temperature. Because of its small-sized grains, the 773K-film showed high rate capability and the discharge capacity at 10μA maintained 65% of that at 25nA. However, the discharge capacity of the 773K-film was ca. 10% smaller than that of the film annealed at 873K, indicating that annealing at 773K is slightly insufficient to obtain well-crystallized LiFePO4. From these results, it was concluded that a point of optimization between high rate capability and capacity would be found between 773 and 873K. [Copyright &y& Elsevier]

An electrochemically stable and cobalt-free cathode material is prepared by impregnating Li 2 MnO 3 with nickel nitrate and subsequent calcination at 650 °C. X-ray diffraction and scanning electron microscopy reveal a phase pure material with a homogenous distribution of nickel over the particle surface. Structural changes related to the treatment before and after cycling as well as electrochemical performance are investigated. The surface modified samples exhibit improved cycling stability and rate capability. In particular, the material with a nickel content of 5.7 wt% shows 173 mAh g −1 at rate C/10 and 104 mAh g −1 at rate 3C. Furthermore, a constant capacity of 155 mAh g −1 is obtained at rate C/5. Derivative plots of galvanostatic curves in combination with Raman spectroscopy depict a reduced transition from a layered to spinel-like structure compared with pristine Li 2 MnO 3 , while ICP measurements reveal a drastically decreased dissolution of manganese. [ABSTRACT FROM AUTHOR]

Abstract: Metal particles were deposited on the surface of solid-state ion conductors by means of a negatively biased AFM tip, and the deposition process was probed by combining chronoamperometric measurements with topographic imaging. It was checked whether the metal particles can act as local electrodes for measuring the local conductivity of the solid-state ion conductor. We found that metallic silver particles on the surface of silver-ion conducting glasses work perfectly as electrodes, even at cathodic voltages below −1V. In contrast, lithium particles deposited on a lithium-ion conducting glass ceramic (LIC-GC) measured a nanoscopic conductivity which was considerably lower than the macrosocopic conductivity. This is most likely due to the fact that the LIC-GC is not stable against metallic lithium, so that a resistive layer is formed at the interface. The surface of the silver-ion conducting glasses was additionally modified with tracks using a laser ablation technique. The sharp edges of tracks triggered the silver deposition, so that metallic silver could be arranged in bands with lateral extensions of about 50μm, when cathodic voltage pulses in the range of −0.4 to −0.6V were applied for a period of 1s or even less. [Copyright &y& Elsevier]

Abstract: The structure and ionic conductivity of a lithium-ion conductive Li–Al–Ti–P–O-type glass ceramic (LATP) was studied by means of powder X-ray diffraction, transmission electron microscopy, and broadband impedance spectroscopy. The results were compared to a Li1.5Al0.5Ge1.5P3O12 (LAGP) ceramic. While the grain conductivity of LATP is higher than that of LAGP, the total conductivity of LATP is lower due to a large grain boundary resistance. The grain boundary resistance of LATP is characterized by a slightly higher activation energy and a slightly higher pre-exponential factor than the grain resistance. Our results indicate that the origin of the grain boundary resistance in these fast lithium ion conductors is clearly distinct from oxide ion conductors. [Copyright &y& Elsevier]

Abstract: An all-solid-state thin film battery consisting of a c-axis-oriented LiCoO2 thin film and a lithium phosphorus oxynitride (LiPON) glass electrolyte was fabricated, and the charge transfer reaction at the LiPON/LiCoO2 interface was investigated. Thermal treatment at 473 K after the formation of the LiPON/LiCoO2 interface improved the reactivity of the film battery, in good agreement with the result previously reported. This improvement was predominantly due to a reduction in charge transfer resistance at the LiPON/LiCoO2 interface. We found that the activation energy of the charge transfer reaction did not change as a result of thermal treatment, indicating that the reduction was not caused by a decrease in activation energy. Because thermal treatment induced a change in chemical bonding in the LiPON film, it is suggested that these structural changes induced some modification at the LiPON/LiCoO2 interface, which resulted in an increase in the number of electrochemically active sites in the contact area. [Copyright &y& Elsevier]

Abstract: An all-solid-state thin-film battery consisting of a c-axis-oriented LiCoO2 thin-film and a lithium phosphorus oxynitride (LiPON) glass electrolyte was fabricated. Thermal treatment at 473K after fabrication of the LiPON/LiCoO2 interface decreased the charge transfer resistance at the interface, and the resistance was further reduced by prolonging the thermal treatment time. The charge transfer resistance per unit electrode area (interfacial resistivity) of a film battery thermal-treated for 60min decreased down to 125Ωcm2, which is ca. five times larger than that in the case of an organic electrolyte (1moldm−3 LiClO4 dissolved in propylene carbonate)/LiCoO2 interface (25Ωcm2). Due to the reduction of the charge transfer resistance at the LiPON/LiCoO2 interface, the reaction current of the film battery was greatly increased by the thermal treatment. Also, thermally treated film batteries showed stable electrochemical lithium insertion/extraction properties compared with the batteries using conventional organic electrolytes. Both the voltammograms and the impedance spectra of the film battery maintained their initial shape for over 100 cycles, and the capacity retention ratio per cycle was calculated to be 99.9%. [Copyright &y& Elsevier]

As confirmed by ion coupled plasma-optical emission spectroscopy and powder X-ray diffraction, stoichiometrically pure samples of olivine type LiFe0.2Mn0.8PO4 in the presence of a phosphoric acid ester based structure directing agent have been prepared. A Rietveld analysis of X-ray and n0 diffraction data suggests that the solids are largely free of defect occupation of Fe at the lithium sites. This is confirmed by 57Fe-Möβbauer spectroscopic investigations. The use of the structure directing surfactant results in significantly higher specific surface areas (SSA) and smaller particle sizes as compared to samples prepared without using a surfactant. [ABSTRACT FROM AUTHOR]

Abstract: Thin films of LiNi0.5Mn1.5O4 (LNMO) were prepared on gold-coated stainless steel substrates via a poly(vinylpyrrolidone)-based sol-gel process. Films with a thickness in the range of 1μm were found to exhibit a capacity close to the theoretical one. The formation of interlayers (i) between the LNMO films and the LP30 electrolyte (mixture of dimethyl carbonate (DMC) and ethylene carbonate (EC) (1:1 v/v) containing 1 mol·l−1LiPF6) and (ii) between the LNMO films and the gold-coated substrate was studied by means of electrochemical impedance spectroscopy (EIS), time-of-flight secondary-ion mass-spectrometry (ToF-SIMS), and scanning transmission electron microscopy together with energy dispersive X-ray spectroscopy (STEM/EDX). The combination of these methods turns out to be very powerful for understanding the chemical composition and properties of interlayers and for identifying the origin of semicircles in Nyquist impedance plots. At the LNMO/LP30 interface, we observe an interlayer (solid electrolyte interface, SEI) with a thickness of about 50 nm, while at the LNMO/gold interface, a mixed oxide layer with a thickness in the range of 250nm is found. The mixed oxide layer is caused by diffusion of Cr and Ni from the stainless steel through the gold layer. While the LNMO/LP30 interlayer contributes significantly to the interfacial impedance, the impedance of the LNMO/gold interlayer seems to be negligible, despite its larger thickness. [Copyright &y& Elsevier]

Abstract: We performed nanoscopic cyclic voltammetry and chronoamperometry on the Ohara lithium ion conductive glass ceramic. When the critical bias voltage was exceeded, metallic lithium particles were deposited irreversibly under the conductive AFM tip acting as working electrode. Due to the huge area difference between working electrode and counter electrode, a reference electrode was not required. We present an in-situ method for studying the particle growth mechanism by simultaneously monitoring the reduction current and the particle height. We found good agreement between the topographically determined volume of the lithium particles and the volume expected from the charge flow. The results for time dependence of the particle growth can be used for controlling the vertical and lateral dimensions of the particles. [Copyright &y& Elsevier]

A study of the lithium ion conductor Li3xLa2/3-xTiO3 solid solution and the surrounding composition space was carried out using a high throughput physical vapor deposition system. An optimum total ionic conductivity value of 5.45 x 10-4 S cm-1 was obtained for the composition Li0.17La0.29Ti0.54 (Li3xLa2/3-xTiO3 x = 0.11). This optimum value was calculated using an artificial neural network model based on the empirical data. Due to the large scale of the data set produced and the complexity of synthesis, informatics tools were required to analyze the data. Partition analysis was carried out to determine the synthetic parameters of importance and their threshold values. Multivariate curve resolution and principal component analysis were applied to the dim-action data set. This analysis enabled the construction of phase distribution diagrams, illustrating both the phases obtained and the compositional zones in which they occur. The synthetic technique presented has Significant advantages over other thin film and bulk methodologies. In terms of both the compositional range covered and the nature of the materials produced. [ABSTRACT FROM AUTHOR]