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Promising metal hydride electrode performance of LaNi4.5Co0.4Al0.1, prepared by induction melting and next hydrogen-induced decrepitation, was proven in the present study. Both the composition and microstructure of the electrode material were found to be responsible for its reliable hydrogen capacity and cycle stability. After prolonged exposure to air, the alloys retain their high hydrogen sorption characteristics, revealing only 10% capacity reduction. The gas phase hydriding of the alloys confirms the hydrogen capacity obtained under electrochemical conditions. Furthermore, the influence of C, Co, and Co3O4 additions to the LaNi5-based alloy on the hydrogen electrode performance was also elucidated. The highest capacity of 300 mAh g−1, remaining constant for 20 cycles, was obtained for LaNi4.5Co0.4Al0.1 + 15 mg Co3O4. This material maintains excellent capacity also at high current densities, making it a suitable electrode material in Ni/MH batteries. [ABSTRACT FROM AUTHOR]

Recently, the interest in developing highly safe rechargeable energy storage systems that are environmentally friendly and integrate that a low cost into the electric grid with electric vehicles now included in the agenda of global energy policies, has grown immensely. As a promising technology, rechargeable zinc-air batteries have received a lot of attention in the last few years. In this research work we focus on the improving the performance of the gasdiffusion electrode (GDE) for secondary Zn-air batteries. A new generation of GDE has been developed and tested in a half-cell configuration. The gas-diffusion layer was developed by heat treated at up to 300°C carbon black. A mixture of Ag and Co3O4 has been used for the bi-functional catalyst in the active layer (AL). Preliminary studies of the gas-diffusion layer (GDL) with different carbon blacks and different ratios between the PTFE and carbon blacks showed that the most stable GDL is produced by Vulcan XC-72 carbon black teflonized with 60 % PTFE. The steady state polarization curves and the charge/discharge tests revealed a superior electrochemical performance of the heat treated carbon material employed in the GDL. [ABSTRACT FROM AUTHOR]