An electrochemical energy conversion and storage system includes an electrochemical energy conversion device, such as a fuel cell that is in fluid communication with a hydrogen or electrically regenerable organic liquid fuel and an oxidant, for receiving, catalyzing and electrochemically oxidizing at least a portion of the fuel to generate electricity, a thus partially oxidized liquid fuel, and water. The liquid fuel includes six-membered ring cyclic hydrocarbons with functional group substituents, wherein the ring hydrogens may undergo an electrochemical oxidative dehydrogenation to the corresponding aromatic molecules. Comprising ring-substituent functional groups may also be electrochemically oxidized now with a potential incorporation of oxygen thus providing an additional capacity for energy storage. The partially oxidized spent liquid fuel may be electrically regenerated in with now an input of electricity and water to the device, generating oxygen as a by-product. Alternatively, the recovered spent fuel may be conveyed to a facility where it is reconstituted by catalytic hydrogenation or electrochemical hydrogenation processes.