Though complex metal hydrides are potential sources of solid state hydrogen storage, practical usage in transportation and power applications is limited by the slow hydrogen adsorption/desorption kinetics and high temperatures for desorption. Experimental observations on transition metal ion-doped sodium alanates reported significant improvement on the hydrogen kinetics at moderate temperatures. However, the actual dopant behavior is still a topic of discussion and the resulting mechanisms leading to changes in the thermodynamic behavior of doped-metal hydrides are still unknown. This work is focused on studying sodium aluminum hydride (NaAlH4) and the role of titanium ion dopants in the improved kinetics of sodium alanates. Density Functional Theory (DFT) geometry optimization calculations are conducted on unit cells and supercells of NaAlH4. Dopant ions replacing native lattice sites are modeled and the electronic density of states and electron density maps around atomic species analyzed to interpret the effect of dopant ions in the sodium alanate cell.
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