Titanium Hydride Nanoplates Enable 5wt%of Reversible Hydrogen Storage by Sodium Alanate below 80℃

Sodium alanate(NaAlH_(4))with 5.6 wt%of hydrogen capacity suffers seriously from the sluggish kinetics for reversible hydrogen storage.Ti-based dopants such as TiCl_(4),TiCl_(3),TiF_(3),and TiO_(2)are prominent in enhancing the dehydrogenation kinetics and hence reducing the operation temperature.The tradeoff,however,is a considerable decrease of the reversible hydrogen capacity,which largely lowers the practical value of NaAlH_(4).Here,we successfully synthesized a new Ti-dopant,i.e.,TiH_(2)as nanoplates with~50 nm in lateral size and~15 nm in thickness by an ultrasound-driven metathesis reaction between TiCl4 and LiH in THF with graphene as supports(denoted as NP-TiH_(2)@G).Doping of 7 wt%NP-TiH_(2)@G enables a full dehydrogenation of NaAlH4 at 80℃and rehydrogenation at 30℃under 100 atm H_(2)with a reversible hydrogen capacity of 5 wt%,superior to all literature results reported so far.This indicates that nanostructured TiH_(2)is much more effective than Tidopants in improving the hydrogen storage performance of NaAlH_(4).Our finding not only pushes the practical application of NaAlH_(4)forward greatly but also opens up new opportunities to tailor the kinetics with the minimal capacity loss.