NOVELTY - The electrochemical energy conversion system comprises an electrochemical energy conversion device (12) such as proton exchange membrane fuel cell in fluid communication with a source of cyclic liquid carrier of hydrogen (14) and an oxidant (15) for receiving, catalyzing and electrochemically oxidizing a portion of hydrogen (16) to generate electricity (18), a hydrogen depleted liquid and water. The liquid carrier of hydrogen comprises an inert additive to facilitate the liquid flow, and an additive to enhance the electrochemical reaction.    USE - The electrochemical energy conversion system is useful for generating electricity for stationary and mobile applications.    ADVANTAGE - The electrochemical energy conversion system is portable and less-weight, can able to safely produce electricity without production of hydrogen gas, provides an attractive hydrogen storage solution and a high-capacity energy storage solution for a combined plug-in electric and pure hydrogen fuel cell vehicles, and can be recharged at night thus regenerating fuel in a cost effective manner.    DETAILED DESCRIPTION - The electrochemical energy conversion system comprises an electrochemical energy conversion device (12) such as proton exchange membrane fuel cell in fluid communication with a source of cyclic liquid carrier of hydrogen (14) and an oxidant (15) for receiving, catalyzing and electrochemically oxidizing a portion of hydrogen (16) to generate electricity (18), a hydrogen depleted liquid and water. The liquid carrier of hydrogen comprises an inert additive to facilitate the liquid flow, and an additive to enhance the electrochemical reaction. A tank is used for storing both the liquid carrier of hydrogen and the hydrogen depleted liquid, and comprises a membrane unit for separating the liquid carrier of hydrogen and the hydrogen depleted liquid. A catalyst is disposed within the electrochemical energy conversion device for assisting the disassociation and oxidation of hydrogen from the liquid carrier of hydrogen. The catalyst comprises finely dispersed metal alloys and transition metal complexes with multidentate P- or N-containing ligands on high-surface-area conductive supports. The proton exchange membrane fuel cell comprises a solid electrolyte. An INDEPENDENT CLAIM is included for method of electrochemical energy conversion.    DESCRIPTION OF DRAWING(S) - The figure shows electrochemical energy conversion system.    Electrochemical energy conversion device (12)    Liquid carrier of hydrogen (14)    Oxidant (15)    Hydrogen (16)    Electricity. (18)