Hydrogen storage properties of rare earth (RE) borohydrides (RE = La, Er) in composite mixtures with LiBH4 and LiH

[摘要] Mixtures of 6LiBH(4)-RECl3-3LiH (RE = La, Er) have been produced by mechanochemical milling and their structure, thermal decomposition and reversibility have been studied. Hydrogen desorption starts around 300 degrees C in both composites. Heating to 400 degrees C yields LaB6, ErB4 and REH2+delta as major decomposition products. LiBH4 is destabilized by REH2+delta formed through decomposition of the parent borohydrides LiLa(BH4)(3)Cl and Er(BH4)(3), respectively, and its hydrogen release temperature is reduced by 100 degrees C as compared to pure ball-milled LiBH4. The lanthanum-containing composite releases 4.2 wt.% H between 300 and 350 degrees C and shows a limited reversibility of similar to 20% (340 degrees C, 10 MPa) probably due to hydrogen uptake by some amorphous boron-containing phases. For 6LiBH(4)-ErCl3-3LiH about 3 wt.% H is evolved up to 400 degrees C. Desorption against 0.5 MPa backpressure results in an increased reversibility (similar to 80%) as compared to vacuum (similar to 66%). Rehydrogenation (340 degrees C, 10 MPa) shows the formation of ErH3 and LiBH4 at drastically reduced conditions compared to pure LiBH4 (>400 degrees C, >10 MPa). (C) 2015 Elsevier B.V. All rights reserved.

[发布日期] 2015-10-05

[效力级别]  Proceedings Paper

[关键词] Borohydride;Rare earth;Hydrogen storage;Composite