MgH_(2),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,LiBH_(4) and YNi_(5) alloy w...MgH_(2),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,LiBH_(4) and YNi_(5) alloy were co-added as additives to MgH_(2) via ball milling,thereby realizing an excellent dehydrogenation per-formance and good cycle stability at 300 ℃.The MgH_(2)-0.04LiBH_(4)-0.01YNi_(5) 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 LiBH_(4) can reversibly absorb and desorb hydrogen throughout the hydrogen ab/desorption process,which contributes a portion of the reversible hydrogen storage capacity to the MgH_(2)-0.04LiBH_(4)-0.01YNi_(5) composite.Due to the small amount of LiBH_(4) and YNi_(5),the dehydro-genation activation energy of MgH_(2) 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 MgH_(2) 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.展开更多
基金National Natural Science Foundation of China(Nos.52271213 and 52271221).
文摘MgH_(2),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,LiBH_(4) and YNi_(5) alloy were co-added as additives to MgH_(2) via ball milling,thereby realizing an excellent dehydrogenation per-formance and good cycle stability at 300 ℃.The MgH_(2)-0.04LiBH_(4)-0.01YNi_(5) 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 LiBH_(4) can reversibly absorb and desorb hydrogen throughout the hydrogen ab/desorption process,which contributes a portion of the reversible hydrogen storage capacity to the MgH_(2)-0.04LiBH_(4)-0.01YNi_(5) composite.Due to the small amount of LiBH_(4) and YNi_(5),the dehydro-genation activation energy of MgH_(2) 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 MgH_(2) 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.
