Thermodynamics of Lithium Storage at Abrupt Junctions: Modeling and Experimental Evidence

We present the thermodynamic modeling and experimental evidence of the occurrence of lithium storage at abrupt junctions, which describes the transition from an electrostatic capacitor to a chemical capacitor. In both $\mathrm{Ru}:{\mathrm{Li}}_{2}\mathrm{O}$ and Ni:LiF systems, the functionalities and extracted parameters are in good agreement with the thermodynamic model, based on the dependence of the storage capacity on open-circuit voltage. Moreover, it is set out that a complete understanding of a conventional storage mechanism requires unifying both the space charge and bulk storage for a nanocrystalline electroactive electrode.