Role of alloying in metal clusters reactivity for lithium-air batteries

It was shown that the rate of LiO₂ formation can be controlled by the size of silver clusters, in connection with lithium-air batteries [1]. A gap at the fermi level was found to control the rate of oxygen reduction at the cathodes [1]. The present study tackles the effects of alloying in the electronic properties of small clusters adsorbed on a hydroxylated alumina surface. Starting from a pristine Pd5 cluster with a 0.32 eV HOMO position from the fermi level, we show that this gap can be controlled by alloying, resulting in a reduction to about 0.15 eV when alloying (single atom) using Ni or Mn. Alloying using a Ru atom resulted in an increase in the HOMO position to 0.49 eV, while for Ag, Au, Pt and Co, this value was found to be 0.2, 0.2, 0.23 and 0.36 eV, respectively. These preliminary results show that alloying may be used to tailor the gap at the fermi level in metal clusters. Results for different levels of stoichiometry (x) as well as different sizes (N) of Pd_N-xM_x will be presented.