Graphene-tailored molecular bonds for advanced hydrogen and lithium storage performance

The practical application of sodium alanate (NaAlH4) as a hydrogen and lithium storage material has attracted intensive attention. The high energy barrier for breaking the Al-H bonds of NaAlH4, however, remains a key challenge. Here, we report that graphene could act as an effective platform to tailor the metal-hydrogen bonds of NaAlH4through their favorable molecular interaction. Theoretical and experimental results confirm that graphene is capable of weakening the Al-H bonds of NaAlH4, thus facilitating the breaking and recombination of Al-H bonds towards advanced hydrogen and lithium storage performance. In addition, owing to this favorable interaction, a robust nanostructure composed of homogeneous NaAlH4nanoparticles with an average size of ~12 nm encapsulated in graphene nanosheets has been developed via a facile solvent evaporation induced deposition method with a tunable loading and distribution. The synergistic effects of the favorable molecular interaction between graphene and NaAlH4and the noticeable decrease in particle size significantly boost the hydrogen and lithium storage performances of NaAlH4. This method provides new avenues to tailoring the molecular bonds of metal hydrides for a new range of applications in various fields.