Biased interface between solid ion conductor LiBH4 and lithium metal: A first principles molecular dynamics study

We use first-principles molecular dynamics to study the electrochemical solid-solid interface between lithium metal and lithium electrolyte LiBH4. An external bias is applied by using an effective screening medium. We observe large polarization in the LiBH4, because the lithium cations in LiBH4 are shifted more on one side of the double-well potential of Li+. This results in a large potential drop in the interface region and a large double-layer capacity corresponding to ca. 70 μF/cm2. H-coordination to the Li atoms plays an important role in the charge-transfer reaction and ion transfer.