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Abstract: Si thin films were deposited directly on stainless steel substrates that act as current collectors using the pulsed laser deposition (PLD) technique. Amorphous Si films of different thicknesses were obtained at the Ar gas pressure of 5×10−5 Torr and a temperature of 500°C but different deposition times. The microstructure and morphology of the films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). The anodic electrochemical performance of the films was examined in the range of 0.005–1.5V, which revealed excellent cyclic stability without any large capacity fade up to the 70th cycle. The PLD process was suitable for improving the density and adhesion behavior of the films. [Copyright &y& Elsevier]

Abstract: A series of polypyrrole-LiFePO4 (PPy-LiFePO4) composites were synthesised by polymerising pyrrole monomers on the surface of LiFePO4 particles. AC impedance measurements show that the coating of polypyrrole significantly decreases the charge-transfer resistance of LiFePO4 electrodes. The electrochemical reactivity of polypyrrole and PPy-LiFePO4 composites for lithium insertion and extraction was examined by charge/discharge testing. The PPy-LiFePO4 composite electrodes demonstrated an increased reversible capacity and better cyclability, compared to the bare LiFePO4 electrode. [Copyright &y& Elsevier]

Abstract: Spherical LiNi0.75Co0.25O2 compounds were synthesized by sintering spherical Ni0.75Co0.25(OH)2 and LiOH·H2O precursors at various temperatures in an oxygen atmosphere. A pure phase LiNi0.75Co0.25O2 could be identified. SEM observation showed that the LiNi0.75Co0.25O2 particles are spherical in shape and are composed of many small crystals. Magnetic susceptibility measurements reveal that the spherical LiNi0.75Co0.25O2 compounds have a more ordered layered structure than that of non-spherical LiNi0.75Co0.25O2. The spherical LiNi0.75Co0.25O2 cathodes demonstrated a stable electrochemical performance in lithium-ion cells with a high reversible capacity of 167mAh/g and good cyclability. [Copyright &y& Elsevier]

Abstract: Several Sn-coated MCMB (mesocarbon microbeads) graphite anode materials were prepared by microencapsulating nanosize Sn particles in MCMB. The nanosized tin particles are homogeneously dispersed in MCMB graphite matrix via electroless in situ chemical reduction. X-ray diffraction and EDS measurement confirms the presence of Sn in MCMB matrix. A systematic electrochemical testing has been performed on the Sn-coated MCMB graphite electrodes. The tin-coated MCMB graphite electrodes demonstrated an improvement in lithium storage capacity. The reaction process of lithium intercalation and de-intercalation in MCMB structure and lithium alloying with tin has been identified by cyclic voltammetry measurement. The micro-encapsulation of Sn in MCMB graphite can enhance the electrochemical properties of MCMB graphite anodes. [Copyright &y& Elsevier]

Abstract: Stoichiometric and non-stoichiometric Mg-doped lithium iron phosphates were synthesised via spray-pyrolysis, followed by sintering at high temperature for crystallization. The spray pyrolysis process allows the homogeneous mixing of the ingredient reactants at atomic level. The electronic conductivities of the Mg-doped lithium iron phosphates have been drastically improved by 4 orders of magnitude, comparing to the undoped LiFePO4. The electrochemical properties of as-prepared lithium iron phosphates were systematically measured by cyclic voltammetry and constant current charge/discharge cycling tests. [Copyright &y& Elsevier]

Abstract: For the first time, carbon-mixed LiFePO4 (LFP) cathode materials have been prepared by spray solution technology. Nominal addition of 15 or 20wt.% C was used in order to simulate the industrial practice for preparation of electrode materials. The prepared powders consist of a single LiFePO4 phase: small crystallites with a highly developed surface area, beneficial for the surface electrochemical processes limited by the low Li diffusion. The combination of spray technology and carbon addition increased the specific surface area above 20m2/g at a relatively high sintering temperature (700°C). The initial discharge capacity was up to 140mAh/g compared to 125mAh/g for conventionally prepared (using a solid state reaction) LiFePO4 electrode materials. [Copyright &y& Elsevier]

Abstract: A novel conducting sulphur-polypyrrole composite material was prepared by the chemical polymerization method with sodium p-toluenesulphonate as the dopant, 4-styrenesulphonic sodium salts as the surfactant, and FeCl3 as the oxidant. The new material was characterized by Raman spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Nanosize polypyrrole particles were uniformly coated onto the surface of the sulphur powder, which significantly improved the electrical conductivity, the capacity and the cycle durability in a lithium cell compared with the bare sulphur electrode. [Copyright &y& Elsevier]

Abstract: “Free-standing” single wall carbon nanotube (SWNT) papers have been synthesised by simple filtration method via positive pressure. A conventional SWNT slurry coated electrode was fabricated to compare with the SWNT papers. The results show that the capacity of the “Free-standing” electrode was slightly lower than that of the conventional electrode, but the “Free-standing” electrode was produced without any binder, and metal substrate, so that the weight of electrode was reduced significantly. On the other hand, the procedures for SWNT electrode preparation were simplified, so the cost of the manufacturing could be reduced. [Copyright &y& Elsevier]