Electrochemical reaction fuel cell system, comprising: a cathode (8), an anode (1), one at least of the anode and of the cathode comprising at least one metal, one metal hydroxide or one metal oxide in the molten state, a solid electrolyte (7), placed between the cathode and the anode, at least one regenerator (4) for regenerating, starting from one at least of the oxidation-reduction reaction products which is recovered at at least one of the anode and of the cathode, by a reaction, at least one of the products constituting at least one of the anode or of the cathode or the fuel or oxidizer consumed at at least one of the anode or of the cathode, one of the regeneration products being reintroduced into the system as electrode made of liquid metal or liquid metal oxide or in the form of fuel or oxidizer, one of the reactions making possible said regeneration or making possible the regeneration of one of the reactants of the oxidation-reduction reaction being endothermic.

A method for manufacturing a vanadium electrolyte is used to solve the problem that the expansive raw material and the additional reducing agent are used in the conventional method. The method comprises: preforming a reduction roasting reaction of ammonium trioxovanadate (V) (NH.sub.4VO.sub.3) at a temperature of 700 C. to 900 C. for a time period of 1 hour to 4 hours to obtain a first vanadium-containing mixture. The first vanadium-containing mixture is dissolved in a first aqueous sulfuric acid solution to obtain the vanadium electrolyte. Accordingly, the manufacturing cost of the vanadium electrolyte is reduced, and the quality of the vanadium electrolyte is improved.

The present disclosure provides a novel power generation element that is advantageous from the viewpoint of being maintenance-free. A power generation element according to the present disclosure includes a first electrode, a second electrode, and an inorganic solid electrolyte. The first electrode splits water. The inorganic solid electrolyte is disposed between the first electrode and the second electrode. Ions generated by the splitting of water at the first electrode are conducted through the inorganic solid electrolyte toward the second electrode. The inorganic solid electrolyte contains at least one selected from the group consisting of a water molecule and a hydroxide ion.

A method of generating electrical energy using an electrochemical direct heat to electricity converter operating on the Rankine cycle is provided. The converter includes a working fluid, a high temperature electrochemical cell including a first membrane electrode assembly, a low temperature electrochemical cell including a second membrane electrode assembly, an evaporator coupled to the first electrochemical cell, a condenser coupled to the second electrochemical cell, and an external load. The method involves introducing the working fluid at the first membrane electrode assembly as a liquid, expanding the working fluid through the first membrane electrode assembly and evaporating it into a vapor, and cooling and condensing the vapor back into a liquid at the second membrane electrode assembly.