Abstract
MgH2,as one of the typical solid-state hydrogen storage materials,has attracted extensive attention.However,the slow kinetics and poor cycle stability limit its application.In this work,LiBH4 and YNi5 alloy were co-added as additives to MgH2 via ball milling,thereby realizing an excellent dehydrogenation per-formance and good cycle stability at 300 ℃.The MgH2-0.04LiBH4-0.01YNi5 composite can release 7 wt.％of hydrogen in around 10 min at 300 ℃ and still have a reversible hydrogen storage capacity of 6.42 wt.％after 110 cycles,with a capacity retention rate as high as 90.3％based on the second dehydrogenation capacity.The FTIR results show that LiBH4 can reversibly absorb and desorb hydrogen throughout the hydrogen ab/desorption process,which contributes a portion of the reversible hydrogen storage capacity to the MgH2-0.04LiBH4-0.01YNi5 composite.Due to the small amount of LiBH4 and YNi5,the dehydro-genation activation energy of MgH2 did not decrease significantly,nor did the dehydrogenation enthalpy(△H)change.However,the MgNi3B2 and in-situ formed YH3 during the hydrogen absorption/desorption cycles is not only beneficial to the improvement of the kinetics performance for MgH2 but also improves its cycle stability.This work provides a straightforward method for developing high reversible hydrogen capacity on Mg-based hydrogen storage materials with moderate kinetic performance.
基金项目
National Natural Science Foundation of China(52271213)
National Natural Science Foundation of China(52271221)
NETL
NSTL
万方数据