Current Effect on the Performances of All-Solid-State Lithium-Ion Batteries—Peukert’s Law

The results from measuring the capacity of thin-film solid-state lithium-ion batteries (SSLIBs) Ti|Si@O@Al|LiPON|LiCoO2|Ti, Ti|Si@O@Al|LiPON|LixV2O5|Ti, and Ti|LiPON|LiCoO2|Ti at different charge currents are reported. It is shown that the dependence of the capacity on the current density Q(j) follows Peukert’s law, which is characterized by a low value of Peukert’s exponents in the region of low currents and a high value of the exponents in the region of high currents. Peukert’s exponent for the anode-free cell remains constant through the entire range of current density variation. A model for SSLIB capacity based on the balance of ion (diffusion and drift) and electron currents is proposed. The model predicts a Q(j) dependence well approximating the experimental results and fitting Peukert’s law. The model allows a qualitative interpretation of the change in the Peukert exponent with increasing current density, based on the effect of the charge current saturation.