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Abstract: Electrochemical performance of Cu2MoS4 was evaluated. When the cutoff potential is limited between 1.6 and 3.0V, the material can give stable cycle performance of up to 100mAhg−1. However, the material shows slow kinetics within this region. The material can give a discharge capacity of up to 653mAhg−1 when discharged to 0.6V vs. Li/Li+, with a first cycle efficiency of 61.3%. This corresponds to an insertion of 8.5Li and an extraction of 5.2Li from the material. XRD and XPS measurements both suggest Cu displacement from the material during discharge and charge, which is a possible reason for the poor cycle stability of the material. A reaction mechanism is proposed based on the XPS analysis. Better cycle performance is observed for Cu2MoS4/GO composite. [Copyright &y& Elsevier]

Abstract: Co3O4 nanoparticles are grown on nitrogen modified microwave exfoliated graphite oxide (NMEG) with weight ratio controlled from 10% to 70%. Electrochemical performance reveals that the obtained Co3O4/NMEG composite as Li-ion battery anode exhibits improved cycle stability, excellent reversible capacity, high current rate performance, and reduced irreversible capacity loss in the initial cycle compared to pure Co3O4 without graphene or Co3O4 on thermally reduced graphene oxide (tRG-O). The 70%Co3O4/NMEG composite has initial irreversible capacity of 230mAhg−1 (first cycle efficiency of 77%), and 910mAhg−1 of capacity is retained after 100 cycles. The 70%Co3O4/tRG-O delivers a reversible capacity of 750±20mAhg−1, and the irreversible capacity loss during the first cycle is 700±20mAhg−1. Nitrogen functional groups in NMEG, especially pyridinic and pyrrolic N are advantageous for the Co3O4 growth. Furthermore, the N modification is effective in reducing the oxygen content of chemically prepared graphene and hence is good for Co3O4 dispersion and the amelioration of first cycle efficiency, demonstrating the potential of NMEG based composite as high performance Li-ion battery anode materials. [Copyright &y& Elsevier]

Free-standing polycrystalline films of Ag, Cu and Ag/Cu multilayers were tested in tension using an optical diffraction grating for the measurement of the strain. The yield stress and the rate of work hardening both increase strongly with decreasing layer thickness. These effects combine to raise the stress for ductile fracture up to 700 MPa and to lower the maximum plastic strain. [ABSTRACT FROM AUTHOR]

Abstract: Thermal stability of charged LiCoO2 cathodes with various surface areas of active material is investigated in order to quantify the effect of LiCoO2 surface area on thermal stability of cathode. Thermogravimetric analyses and calorimetry have been conducted on charged cathodes with different active material surface areas. Besides reduced thermal stability, high surface area also changes the active material decomposition reaction and induces side reactions with additives. Thermal analyses of LiCoO2 delithiated chemically without any additives or with a single additive have been conducted to elaborate the effect of particle size on side reactions. Stability of cathode–electrolyte system has been investigated by accelerating rate calorimetry (ARC). Arrhenius activation energy of cathode decomposition has been calculated as function of conversion at different surface area of active material. [Copyright &y& Elsevier]