Novel lithium metal polymer solid state batteries with nano CLiFePO4 , nano Li1.2V3O8 counter-electrodes (average particle size 200 nm) and NMC were studied for the first time by in situ SEM and impedance during cycling. The kinetics of Li-motion during cycling is analyzed self-consistently together with the electrochemical properties. We show that the cycling life of the nano Li1.2V3O8 is limited by the dissolution of the vanadium in the electrolyte, which explains the choice of nano C-LiFePO4 (1300 cycles at 100% DOD): with this olivine, no dissolution is observed. In combination with lithium metal, at high loading and with a stable SEI an ultrahigh energy density battery was thus newly developed in our laboratory. The electrochemical of new polymer with high voltage with NMC cathode material will show during this presentation. The commercial use of lithium metal batteries was delayed because of dendrite formation on the surface of the lithium electrode, and the difficulty finding a suitable electrolyte that has both the mechanical strength and ionic conductivity required for solid electrolytes. Recently, strategies have developed to overcome these difficulties, so that these batteries are currently an option for different applications, including electric cars. In this work, we review these strategies, and discuss the different routes that are promising for progress in the near future. We will explain the Gen 2 solid state lithium metal battery technology: from the laboratory to commercialization.

The research on the electrodes of Li-ion batteries aims to increase the energy density and the power density, improve the calendar and the cycling life, without sacrificing the safety issues. A constant progress through the years has been obtained owing to the surface treatment of the particles, in particular the coating of the particles with a layer that protects the core region from side reactions with the electrolyte, prevents the loss of oxygen, and the dissolution of the metal ions in the electrolyte, or simply improve the conductivity of the powder. The purpose of the present work is to review the different surface modifications that have been tried in the past for the different electrodes that are currently commercialized, or considered as promising, including the three families of positive electrodes (lamellar, spinel, and olivine families) and the three negative electrodes (carbon, Li 4 Ti 5 O 12 , and silicon). The role of the different coats used to improve either the surface conductivity, or the thermal stability, or the structural integrity is discussed. The limits in the efficiency of these different coats are also analyzed along with the understanding of the surface modifications that have been proposed.

Raman scattering and IR absorption were studied in Li-intercalated MoS2 at room temperature. After intercalation, new Raman peaks were observed at low-frequency sides of the high-frequency original Raman peaks and around a rigid-layer mode. This fact indicates the formation of superlattice structure along the c-axis. An intercalation mode in which Li atoms vibrate strongly against the host lattice was observed at about 205 cm−1. Two new broad bands grow in the high-frequency region as the concentration of Li increases. The corresponding peaks were observed by IR absorption. They appears to be caused by vibrations of substitutional defects, in which the Li atoms have substituted for Mo atoms in the host lattice.

We report electrical properties of the lithium manganospinel LiMn2 O 4 and its delithiated/lithiated forms, Li1−x+∂Mn2−∂O4 with 0.0≤x≤0.4 and 0.00≤∂0.18. The electrical conductivity has been determined from d.c. measurements as a function of temperature and lithium content in the host lattice. LiMn2O4 exhibits a phase transition in the vicinity of 280 K, which disappears in the lithium-rich samples. Electrical data are analysed using the model of small-polaron transport. ESR spectroscopy has been applied to identify the singular structural features. Investigations as a function of temperature show a reliable determination of the modifications in the cationic sublattice and of the lithium overstoichiometry. The hopping conductivity mechanism between the Mn3+ and Mn4+ sites gives a coherent explanation for the observed ESR signal of cyclotron resonance.

We report the vibrational spectra of various layered transition-metal oxides, which are potential cathode materials for advanced Li-ion batteries. They provide high specific energy density, high voltage, and remarkable reversibility for lithium intercalation-deintercalation process. Studies were carried out by Raman and FTIR spectroscopies. Oxides such as LiMO2 (M=Co, Ni, Cr) layered compounds and their mixed compounds have been investigated. The local environment of cations against oxygen neighboring atoms has been determined by considering polyhedral units building the lattice. Structural modifications induced by intercalation-deintercalation process, by cation substitution, or by low-temperature preparation route are examined.

Oxide-hydrates of molybdenum [OHM] are investigated as 3-volt cathode materials for rechargeable lithium batteries. The oxides and oxide-hydrates of molybdenum have been prepared at various degrees of heat treatment. The oxide-hydrates of molybdenum with different water content showed a much better performance as cathode of the rechargeable lithium battery than that of MoO 3 . From these results, it was found that the crystalline-bonded water molecules play an important role for the high discharge capacity and high cyclability. We report the electrochemical characteristics of Li/OHM batteries using the oxides and oxide-hydrates of molybdenum which have been prepared with various degrees of heat treatment of molybdic acid. The oxide has a corrugated layer structure consisting of corner-shared MoO 6 octahedra. This structure provide electronic conductivity within a layer and high lithium ion mobility between layers. The mechanism of dehydration and structural rearrangement of molybdic acid during heat treatment were studies by thermal analysis, X-ray diffraction, Raman and infrared spectroscopy. Thermal analysis indicates a two-step dehydration and formation of orthorhombic α-MoO 3 and monoclinic β-MoO 3 . Discharge profiles and kinetics of the materials are dependent on the amount of “structural water” into the host lattice. The electro-insertion of Li ions occurs mainly in two steps in the potential range between 3.0 and 1.5 V (compositional range 0<x Li <l.5). Kinetic measurement show that Li ions are highly mobile in the OHM framework. The partial molar quantities δG x , δS x , and δH x , estimated from EMF-temperature measurements and coulometric titration.

LiFePO4 (LFP) nano-particles have been obtained by grinding ingot synthesized in the molten state. This process, followed by jet milling, and then wet milling, provides a simple way to obtain powders with monitored size of the particles in the whole range from macroscopic to 25 nm, although at this stage, we find that these particles tend to segregate to form secondary particles of size ~100 nm. The electrochemical performance of LFP particles has been evaluated in Li/1M LiPF6 in EC:DEC (1:1)/C-LiFePO4 cells. After carbon coating, LFP particles can be obtained free from any impurity, with a high rate capability. Even with an amount of carbon limited to 2 wt.% appropriate to commercial batteries, the capacity is 157 mAh/g at 0.1C; 58 mAh/g at 10C without capacity fading after 60 cycles.

We report on the growth of molybdenum and vanadium oxide films, i.e., MOO3, V2O5, and V6O13, and their application as positive electrodes in lithium microbatteries. We have characterized various polycrystalline samples and studied how their structural and electrical properties are affected by the different preparation conditions. The highest quality films were grown on silicon substrate maintained at 250°C and annealed at 300°C. It is shown that the growth conditions play an important role in the electrochemical properties of the film. Both thermodynamic and kinetic parameters are strongly dependent on film morphology and stoichiometry. Microbatteries fabricated with cathodes formed at moderate temperature have shown a volumetric capacity about 80 μAh/μm/cm2. The cells exhibit a monotonous discharge profile indicating that the cathode materials remain single phase even for a large degree of intercalation.

We have studied the modifications of structural and physical properties which occur during delithiation of lithium-nickel-cobalt oxide cathode materials. Long-range and short-range orders have been investigated using XRD, Raman and FTIR spectroscopies. Different samples Li x Ni 0.7 Co 0.3 O 2 (0.5≤x≤1) were prepared by electrochemical lithium deintercalation from Li x Ni 0.7 Co 0.3 O 2 . Electrochemical extraction of lithium was carried out using Li/LiCIO 4 in PC/Li x Ni 0.7 Co 0.3 O 2 cells in the potentiometric method with potential step of 10 mV. During the first charge of the Li//Li x Ni 0.7 Co 0.3 O 2 cell, the change in the cathode structure was followed by x-ray powder diffraction and vibrational spectroscopies at room temperature. A good correlation is found between XRD data and the local environment of the host lattice. Detailled analysis of vibrational spectra shows that the octahedral oxygen environment of Li + ions remains stable in the investigated domain of concentration.

LiFePO4 nano-particles have been prepared by grinding ingot synthesized in the molten state. Formatting 25-nanometer particles was obtained by subsequent jet and wet milling. These primary particles tend to segregate to form secondary particles of size ∼100 nm, for which surface effects become increasingly important. Study of the electrochemical properties of Li//LiFePO4 cells showed that the cell performance appeared to be strongly dependant of the synthetic route used. The best electrode material formed by wet milling followed by 2 wt.% carbon coating delivered discharge capacity of 157 mAh g-1 at C/10 rate without capacity fading after 60 cycles.

The layered semiconductor InSe which is a potential insertion cathode for thin film batteries can be intercalated with lithium which act as donor in the host. Chemical intercalation in n-butyllithium, leads to a drastic increase of the free carrier density in the host material, InSe single crystal. The variation of the free carrier density with intercalation shifts the plasma frequency into the region of the LO-mode vibrations and allows the observation of the plasmon-LO-phonons coupling by light scattering experiments. By varying the sample temperature, it is possible to follow the two branches of the curve ω(q) corresponding to the modes L+ and L-.