IFISUR   23398
INSTITUTO DE FISICA DEL SUR
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Effects of charged defects on MgH2 storage properties: A DFT Study
Autor/es:
GAZTAÑAGA, F.; F. ESCUDERO; P. V. JASEN; C. R. LUNA; G. BRIZUELA; M. SANDOVAL; J. JUAN
Lugar:
Liverpool
Reunión:
Congreso; 3rd International Conference on Nanotechnology, Nanomaterials & Thin Films for Energy Applications? (NANOENERGY 2016); 2016
Resumen:
Magnesium hydride (MgH2) is considered a promising candidate as material for hydrogen storage due to its low cost, availability and non-toxicity, among others. However, the MgH2 activation energy for hydrogen kinetic desorption is relatively high [1]. One alternative for this inconvenient is the addition of transition metals (TM) or defects like vacancies [2]. The goal of this study is to elucidate the chemical and physical changes by DFT calculations due to charged vacancies incorporation in MgH2. Particularly, were considered a H vacancy (VH), or a Mg vacancy (VMg) or a di-vacancy H-Mg (VH-Mg) in MgH2. For each vacancy were taken into account three possible charge states (q = +1, 0 and −1). The results show that the H vacancy formation is the most stable. And most important band gap reductions are for and , around 65.4 % and 68.8% respectively. Regarding to vacancy incorporation it can be seen that the changes more significant are in the band gap zone, the valence and conduction band practically no change. Depending of charge states of them there is a band gap reduction and appears a magnetic moment. The most important induced magnetic moment is in the case of (~0.74 µB). Moreover, the and generate additional states in the band gap zone. This fact leads the system to an n-type semiconductor behavior for while in the rest of cases are a p-type semiconductor. Finally, it can be concluded from the results that charged vacancies incorporation improve the H dissociation and conduce to interesting electronic properties.