Molten metal battery system with self-priming cells

A battery cell capable of self-priming with molten metal produced within the battery cell includes a cathode compartment configured to contain a catholyte that releases metal ions, an anode compartment at least partially containing an anode current collector that receives electrons from an external power supply, an ion-selective membrane positioned between the cathode compartment and the anode compartment and configured to selectively transport the metal ions from the cathode compartment to the anode compartment when self-priming the battery cell, and an electron transport structure extending between the anode current collector and the ion-selective membrane within the anode compartment and configured to transport the electrons from the anode current collector to the ion-selective membrane when self-priming the battery cell. Self-priming includes combining the electrons with the metal ions arriving at an interface between the electron transport structure and the ion-selective membrane to produce the molten metal within the anode compartment.