C. Julien

Solid State Batteries: Materials Design and Optimization

Preface. 1. Design and Optimization of Solid-State Batteries. 2. Materials for Electrolyte: Crystalline Compounds. 3. Materials for Electrolyte: Fast-Ion-Conducting Glasses. 4. Materials for Electrolyte: Thin Films. 5. Polymer Electrolytes. 6. Materials for Electrodes: Crystalline Compounds. 7. Materials for Electrodes: Amorphous and Thin-Films. 8. Applications of Solid-State Ionic Materials. Subject Index.

Advanced Electrodes for High Power Li-ion Batteries

While little success has been obtained over the past few years in attempts to increase the capacity of Li-ion batteries, significant improvement in the power density has been achieved, opening the route to new applications, from hybrid electric vehicles to high-power electronics and regulation of the intermittency problem of electric energy supply on smart grids. This success has been achieved not only by decreasing the size of the active particles of the electrodes to few tens of nanometers, but also by surface modification and the synthesis of new multi-composite particles. It is the aim of this work to review the different approaches that have been successful to obtain Li-ion batteries with improved high-rate performance and to discuss how these results prefigure further improvement in the near future.

Optical and electrical characterizations of SnSe, SnS2 and SnSe2 single crystals

Abstract This work reports a study of the optical and electrical properties of tin monoselenide SnSe and tin dichalcogenides SnX2 with X = S and Se . The semiconducting character of the single crystals is investigated by means of resistivity and Hall effect in the temperature range from 90 to 300 K. The energy gap data are obtained by absorption measurements. The far-infrared reflectance spectra of the tin chalcogenide compounds have been measured. The experimental data are fitted using a four-parameter dispersion model based on the factorized form of the dielectric function.

Infrared studies of the structure of borate glasses

Abstract Infrared spectroscopy investigations of binary glasses B 2 O 3  xLi 2 O with 0 x 1 have been performed in order to understand the glass-modifying properties of Li 2 O. The mid-reflectivity spectra show clearly the disappearance of boroxol rings and the formation, in a first step, of tetraborate groups and later of diborate groups as the oxide content increases. For high values of ξ, borate groups with non-bridging oxygen atoms are formed. One band at about 390 cm −1 is attributed to vabration of the lithium ions. Modifications of the boron-oxygen network with the addition of lithium sulphate as a doping salt have also been investigated in the ternary system B 2 O 3  xLi 2 OyLi 2 Si 4 . At the same time, by far-infrared absorption on the binary glass, the vibrational motion of the lithium cations has been confirmed.

Integrable lithium solid-state microbatteries

Abstract Thin, micro-solid-state lithium batteries using lithium borate glass as electrolyte and InSe, In 2 Se 3 layered cathodes have been obtained recently by flash evaporation or molecular beam deposition techniques. Thin cells grown by flash evaporation, having an area of 1 cm 2 and a cathode mass of 2 mg, present an average OCV of 1.6 V, giving a practical capacity of Q = 38 μ A h, corresponding to a volume capacity of 57 A h l −1 . Molecular beam deposited cells having an In 2 Se 3 cathode 3.5 μm thick show an OCV of 1.2 V.

Lithium intercalation studies in hydrated molybdenum oxides

Abstract Hydrated molybdenum-trioxides MoO 3 · nH 2 O were synthesized via the condensation of molybdic acid in aqueous solutions. These hydrated oxides are studied by thermal analysis, X-ray diffraction and FTIR spectroscopy. The electrochemical properties, i.e. thermodynamics and kinetics, of lithium-intercalated MoO 3 · nH 2 O cathodes are investigated in relation to their structure and morphology. These compounds show good charge-discharge cyclic behaviour at a capacity of below 1.5 e − /Mo. The electrochemical features of these materials are compared with those of other molybdic acids, i.e. MoO 3 · ( 2 3 )H 2 O, MoO 3 · 1H 2 O and MoO 3 · 2H 2 O . The chemical diffusion coefficient of Li + ions reaches a value 3 × 10 −9 cm 2 s −1 in MoO 3 · ( 1 2 )H 2 O materials.

Structural studies of MoS2 intercalated by lithium

Abstract Defects created by intercalation in MoS2 single crystals were studied by plane and cross-sectional electron microscopy. In the first stage of intercalation the effect is to create extensive dislocations. Further intercalation leads to a structural transformation of the type 2H → 1T , as is evident from the appearance of spots in the diffraction pattern belonging to the new phase. In addition, the transformation is accompanied by a 2a 0 × 2a 0 superstructure. This superstructure is unstable and disappears on heating, while the structural transformation is irreversible.

Growth conditions of InxSey films by molecular beam deposition

Abstract The growth conditions of thin films of In x Se y obtained by molecular beam deposition have been studied. The influence of the fluxes of effusion elements and the substrate temperature dependences have been investigated by the characterization of the thin film structure. X-ray patterns and Raman scattering spectra show that In 4 Se 3 , InSe and In 2 Se 3 can be formed in a wide range of elemental fluxes.

Glass formation and structural studies of chalcogenide glasses in the CdSGa2S3GeS2 system

Abstract Ga2S3 forms stable glasses with GeS2 over a wide range of compositions and, in the same system, more complex glasses are obtained by dissolving CdS. Differential thermal analysis is used to investigate Tg, Tc and endothermic peaks. The glass forming region is reported in the phase diagram. Raman scattering and far-IR absorption spectra of compositions probing the glass-forming region of the ternary Ga2S3GeS2CdS have been studied. The vibrational assignment is discussed and the modifying role of CdS addition is investigated.

Optimization of growth conditions for In2Se3 films

Abstract Thin films of In 2 Se 3 were grown onto different substrates by flash and thermal evaporation at temperatures ranging from 50 to 250°C and their structure and electrical conductivity studied. The influence of annealing of resistant polycrystalline thin films in neutral atmosphere on the basic transport parameters is reported. It is deduced that the α to β phase transition in In 2 Se 3 thin films occurs around 200°C, as in the case of single crystals. The direct gap of α-In 2 Se 3 and β-In 2 Se 3 films determined from optical absorption measurements is found to be 1.45 and 1.53 eV respectively, close to the single-crystal values.