Abstract
In this study, the modification of the desorption behavior of LiAlH(4) by the addition of K(2)NbF(7) was explored for the first time. The addition of K(2)NbF(7) causes a notable improvement in the desorption behavior of LiAlH(4). Upon the addition of 10 wt.% of K(2)NbF(7), the desorption temperature of LiAlH(4) was significantly lowered. The desorption temperature of the LiAlH(4) + 10 wt.% K(2)NbF(7) sample was lowered to 90°C (first-stage reaction) and 149°C (second-stage reaction). Enhancement of the desorption kinetics performance with the LiAlH(4) + 10 wt.% K(2)NbF(7) sample was substantiated, with the composite sample being able to desorb hydrogen 30 times faster than did pure LiAlH(4). Furthermore, with the presence of 10 wt.% K(2)NbF(7), the calculated activation energy values for the first two desorption stages were significantly reduced to 80 and 86 kJ/mol; 24 and 26 kJ/mol lower than the as-milled LiAlH(4). After analysis of the X-ray diffraction result, it is believed that the in situ formation of NbF(4), LiF, and K or K-containing phases that appeared during the heating process promoted the amelioration of the desorption behavior of LiAlH(4) with the addition of K(2)NbF(7).