Chemical compound

Role

Redox-active functional groups

Electrical energy storage, electrical charge formation, interference in electrons flow, ions absorption [16]

Metals

Electrical energy storage, mineral phase formation, participation in redox reactions [18]

Free radicals

Electrical energy storage [19]

Amorphous carbon

Serves as semipermeable membrane, formation of carbon-phase net [20]

Graphitic carbon

Serves as semipermeable membrane, formation of carbon-phase net [20]