Facile synthesis of spinel CuCo2O4 nanocrystals as high-performance cathode catalysts for rechargeable Li-air batteries.

CuCo2O4 nanoparticles have been synthesized by a simple and low-cost urea combustion method and characterized as bifunctional catalysts for non-aqueous Li-air batteries. The resulting CuCo2O4 catalyst has been demonstrated to effectively reduce the charge-discharge polarization of Li-air batteries in a simulated air environment (80% Ar : 20% O2).

Facile hydrothermal synthesis of CuFeO2 hexagonal platelets/rings and graphene composites as anode materials for lithium ion batteries.

Delafossite CuFeO2 hexagonal platelets/rings and graphene composites were synthesized by a low temperature hydrothermal method. The formation mechanism of CuFeO2 hexagonal platelets/rings follows the combined effects of both GO and NaOH. The obtained composites as anode materials display a good battery performance with high reversible capacity, good rate capability and cyclic stability.

Layered Li2MnO3·3LiNi(0.5-x)Mn(0.5-x)Co(2x)O2 microspheres with Mn-rich cores as high performance cathode materials for lithium ion batteries.

Layered Li2MnO3·3LiNi0.5-xMn0.5-xCo2xO2 (x = 0, 0.05, 0.1, 0.165) microspheres with Mn-rich core were successfully synthesized by a simple two-step precipitation calcination method and intensively evaluated as cathode materials for lithium ion batteries. The X-ray powder diffractometry (XRD) results indicate that the growth of Li2MnO3-like regions is impeded due to the presence of cobalt (Co) in the material. The field-emission scanning electron microscopy (FESEM) data reveal the core-shell-like structure with a Mn-rich core in the as-prepared particles. The charge-discharge testing reveals that the capacity is markedly improved by adding Co. The activation of the cathode after Co doping becomes easier and can be accomplished completely when charged to 4.6 V at the C/40 rate in the initial cycle. Superior electrochemical performances are obtained for samples with x = 0.05 and 0.1. The corresponding initial discharge capacities are separately 281 and 285 mA h g(-1) at C/40 between 2 and 4.6 V at room temperature. After 250 cycles at C/2, the respective capacity retentions are 71.2% and 70.4%, which are better compared to the normal Li-excess Li2MnO3·3LiNi0.4Mn0.4Co0.2O2 sample with a uniform distribution of Mn element in the particles. The initial discharge capacities of both samples are approximately 250 mA h g(-1) at a rate of C/2 between 2 and 4.6 V at 55 °C after activation. Furthermore, the samples are investigated by electrochemical impedance spectroscopy (EIS) at room and elevated temperature, revealing that the key factor affecting electrochemical performance is the charge transfer resistance in the particles.