Thermodynamics of lithium storage at abrupt junctions: Modeling and experimental evidence

Lithium storage at abrupt junctions is addressed by thermodynamic modeling, and the results are corroborated by experiments, which describe the transition from an interfacial capacitor to a chemical intercalation capacitor. For both Ru:Li₂O and Ni:LiF systems, the analysis based on the dependence of storage capacity on voltage indicates that the functionalities and extracted parameters are in good agreement with the thermodynamic model. We also emphasize that a complete understanding of a conventional storage mechanism requires unifying both space charge and bulk storage, in particular but not exclusively for nanocrystalline electrodes.