Enhanced hydrogen desorption properties of LiAlH4 by doping lithium metatitanate

Abstract

High efficiency catalysts are needed to improve the kinetics of complex hydrides for practical applications. In this study, lithium metatitanate (Li₂TiO₃) is introduced in lithium alanate (LiAlH₄), and the catalytic effect for notable complex/metal hydrides, such as LiAlH₄, is investigated. Experiment results indicate that Li₂TiO₃ improves the kinetics of LiAlH₄. In particular, Li₂TiO₃ dramatically improves the onset temperature of LiAlH₄, which decreases to 75 °C and is within the temperature range for use in proton exchange membrane fuel cells. Transmission electron microscopy (TEM) observations help understand the catalytic effect of Li₂TiO₃ in the nanoscale. First principles calculations also show the improvement of H⁻ and Li⁺ mobility by doping Li₂TiO₃, where calculations indicate that the physical origin of the catalytic effect is due to two factors: charge transfer and minor surface relaxation. Thus, experimental and theoretical evidence reveals the catalytic mechanism of Li₂TiO₃ in LiAlH₄.