with ions arriving at the interface from the electrolyte and electrons from the external
circuit through the electronic current collector. This results in the deposition A
atoms onto the adjacent solid phase AB. The A/electrolyte interface and the electrolyte/
AB interface move incrementally to the left in Fig. 1.2. Interdiffusion of A
and B atoms within the phase AB is necessary to ensure that its surface does not
have only A atoms. In addition, this phase must be an electronic conductor.