2LiBH4–MgH2 nanoconfined into carbon aerogel scaffold impregnated with ZrCl4 for reversible hydrogen storage

Abstract Nanoconfinement of 2LiBH 4 –MgH 2 composite into carbon aerogel scaffold (CAS) impregnated with zirconium (IV) chloride (ZrCl 4 ) for reversible hydrogen storage is proposed. Nanoconfined samples prepared with hydride:ZrCl 4 -doped CAS weight ratios of 1:1, 1:2, and 1:3 are prepared by melt infiltration technique. Successful nanoconfinement of all samples is confirmed and it is found that the sample with high content of hydride with respect to ZrCl 4 -doped CAS (1:1 weight ratio) shows partial pore blocking. The most suitable hydride:ZrCl 4 -doped CAS weight ratio providing the best performance based on dehydrogenation temperature and kinetics as well as hydrogen storage capacity is 1:2. Reduction of dehydrogenation temperature and faster kinetics are obtained after doping with ZrCl 4 . Up to 97 and 93% of theoretical hydrogen storage capacity are released and reproduced after four cycles of nanoconfined sample with ZrCl 4 (1:2 weight ratio). Deficient hydrogen content with respect to theoretical capacity can be due to partial dehydrogenation during melt infiltration and formation of thermally stable [B 12 H 12 ] 2- phases during cycling.