Improved reversible dehydrogenation properties of LiBH_4-MgH_2 composite by tailoring nanophase structure using activated carbon

摘要

In this study, activated carbon (AC) was added to the 2LiBH_4-MgH_2 composite and examined with respect to its effect on the hydrogen storage properties of the system. Our study found that AC is an effective additive for promoting the reversible dehydrogenation of the 2LiBH_4-MgH_2 composite. A series of control experiments were carried out to optimize the sample preparation method, milling time and addition amount of AC. In comparison with the neat LiBH_4-MgH_2 system, the LiBH_4-MgH_2-AC composite prepared under optimized conditions exhibits enhanced dehydrogenation kinetics, improved cyclic stability and particularly, eliminated incubation period between the two dehydrogenation stages. A combination of phase/microstructure/chemical state analyses has been conducted to gain insight into the promoting effect of AC on the reversible dehydrogenation of the 2LiBH_4-MgH_2 system. Our study found that AC exerts its promoting effect via tailoring nanophase structure of the 2LiBH_4-MgH_2 composite.