Core–Shell NaBH4@Na2B12H12 Nanoparticles as Fast Ionic Conductors for Sodium-Ion Batteries

Herein, we report on a method to engineer a conductive interface to promote high Na+ ionic conductivity in NaBH4. By controlled reaction with B2H6, the ionic conductivity of NaBH4 is enhanced by 5 orders of magnitude at room temperature. The origin of the enhanced conductivity is believed to be the result of the formation of a Na2B12H12 layer on the surface of α-NaBH4 particles. The resultant NaBH4@Na2B12H12 heterostructure exhibits a high ionic conductivity of 10–4 S cm–1 at 115 °C superior to that of pristine NaBH4 and shows the potential to act as a solid-state electrolyte for all Na solid-state batteries.