  As all-solid-state batteries (SSBs) develop as an alternative to traditional
cells, a thorough theoretical understanding of driving forces behind battery
operation is needed. We present a fully first-principles-informed model of
potential profiles in SSBs and apply the model to the
Li/LiPON/$\text{Li}_x\text{CoO}_2$ system. The model predicts interfacial
potential drops driven by both electron transfer and Li$^+$ space-charge layers
that vary with the SSB's state of charge. The results suggest lower electronic
ionization potential in the solid electrolyte favors Li$^+$ transport, leading
to higher discharge power.
