Enhanced hydrogen generation by hydrolysis of LiBH 4 doped with multiwalled carbon nanotubes for micro proton exchange membrane fuel cell application

Abstract

LiBH 4 has a high hydrogen storage capacity and could potentially serve as a superior hydrogen storage material. However, during the hydrolysis process for hydrogen generation, the agglomeration of the hydrolysis product of LiBH 4 limits its full utilization. In order to completely release the stoichiometric amount of H 2 from LiBH 4 hydrolysis, multiwalled carbon nanotubes (MWCNTs) were doped with LiBH 4 by mechanical milling. The results show that MWCNT carried LiBH 4 can slowly react with water vapor at room temperature which is 25 °C lower than the reaction temperature of neat LiBH 4. Agglomeration can be avoided when the addition of MWCNTs exceeds 7 wt.%, which results in a complete hydrolysis process. The total hydrogen capacity is 7.5 wt.%. The enhanced hydrolysis of LiBH 4 can be attributed to the MWCNTs which increased the contact areas between LiBH 4 and water and created gas channels for hydrogen diffusion. The performance of a micro proton exchange membrane fuel cell connected to MWCNT-doped LiBH 4 powder packed-bed reactor was examined. The result demonstrates that doping with MWCNTs enhanced the hydrogen generation of LiBH 4 hydrolysis. MWCNT-doped LiBH 4 can be applied as hydrogen source of fuel cells.