Stable bromine charge storage in porous carbon electrodes using tetraalkylammonium bromides for reversible solid complexation

An energy storage device, comprising:

• an electrical double layer capacitor (EDLC) including:
• one or more cells, each cell including:
• a pouch having a first wall and a second wall, the first wall and the second wall each comprising a current collector including a carbon-polymer composite;
• a plastic spacer, a first electrode, a second electrode , an electrolyte, and a separator inside the pouch;
• and
• a seal between the first wall and the second wall so that the plastic spacer, the first electrode, the second electrode, the electrolyte, and the separator are sealed inside the pouch;
• and wherein:
• the first electrode and the second electrode are in contact with the electrolyte,
• the electrolyte includes a first redox couple comprising bromine or a bromine moiety and a second redox couple comprising a viologen;
• during charging, the electrolyte evolves into a catholyte including the first redox couple and an anolyte including the second redox couple;
• and
• when charged, the charge is stored in Faradaic reactions with the first redox couple and the second redox couple in the electrolyte and in a double-layer capacitance of athc porous carbon material that comprises at least one of the first electrodecicctrodcs or the second electrode.