Improvement of thermal stability and reduction of LiBH4/polymer host interaction of nanoconfined LiBH4 for reversible hydrogen storage

Abstract Addition of multi-wall carbon nanotube (MWCNT) and NaAlH 4 into nanoconfined LiBH 4 –PcB (poly (methyl methacrylate)–co–butyl methacrylate) for improving thermal stability and reducing LiBH 4 /PcB interaction is proposed. The greater the amount of gases desorbed due to polymer (PcB) degradation, the less the thermal stability of polymer host. During dehydrogenation of nanoconfined LiBH 4 –PcB, combination of gases due to PcB degradation is 64.3% with respect to H 2 content, while those of nanoconfined samples doped with MWCNT and NaAlH 4 are only 9 and 7.9%, respectively. The LiBH 4 /PcB (i.e., B⋯OCH 3 ) interaction is quantitatively evaluated by FTIR technique. The more the ratio of peak area between υ(B–H) (from LiBH 4 ) and υ(C O) (from PcB), the lower the LiBH 4 /PcB interaction. It is found that by adding small amount of MWCNT and NaAlH 4 , this ratio significantly increases up to 78%. This is in agreement with B 1 s XPS results, where the relative amount of B x O y ( x /y = 3) to LiBH 4 decreases after adding MWCNT and NaAlH 4 into nanoconfined LiBH 4 –PcB. It should be remarked that significant improvement of thermal stability and decrease of LiBH 4 /PcB interaction after adding MWCNT and NaAlH 4 into nanoconfined LiBH 4 –PcB result in considerable amount of hydrogen release and uptake as well as hydrogen reproducibility during cycling. However, the dispersion of MWCNT is still one of the most critical factors to be concerned due to probably its hindrance for hydrogen diffusion.