A thermo-electrochemical converter is provided. The converter includes a working fluid, coupled first and second membrane electrode assemblies (MEA), first and second heat transfer members, a heat sink and a heat source. Each MEA includes a first porous electrode operating at a first pressure, a second porous electrode operating at a second pressure which is higher than the first pressure, and an ion conductive membrane sandwiched therebetween. The first MEA compresses the working fluid and the second MEA expands the working fluid. The first heat transfer member is coupled to and thermally interfaces with a low-pressure electrode of the first MEA. The second heat transfer member is coupled to and thermally interfaces with a lowpressure electrode of the second MEA. The heat sink is coupled to the low-pressure side of the first MEA and the heat source is coupled to the low-pressure side of the second MEA.

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.

A heat to electricity converter including a working fluid and a pair of membrane electrode assemblies (MEA) is provided. Each MEA includes a pair of electrodes which are electron conductive and permeable to the working fluid, and a thin film electrolyte membrane sandwiched between the electrodes. The membrane is conductive of ions of the working fluid and has a thickness of 0.03 μm to 10 μm. At least one electrode of each MEA includes a non-porous and dense metal. One electrode of each MEA is in contact with the working fluid at a first, higher pressure, while the other electrode is in contact with the working fluid at a second, lower pressure. The first MEA is configured to compress the working fluid from the second pressure to the first pressure, while the second MEA is configured to expand the working fluid from the first pressure to the second pressure.

A direct thermoelectrochemical heat-to-electricity converter includes two electrochemical cells at hot and cold temperatures, each having a gas-impermeable, electron-blocking membrane capable of transporting an ion I, and a pair of electrodes on opposite sides of the membrane. Two closed-circuit chambers A and B each includes a working fluid, a pump, and a counter-flow heat exchanger. The chambers are connected to opposite sides of the electrochemical cells and carry their respective working fluids between the two cells. The working fluids are each capable of undergoing a reversible redox half-reaction of the general form R.fwdarw.O+I+e.sup.−, where R is a reduced form of an active species in a working fluid and O is the oxidized forms of the active species. One of the first pair of electrodes is electrically connected to one the second pair of electrodes via an electrical load to produce electricity. The device thereby operates such that the first electrochemical cell runs a forward redox reaction, gaining entropy, and the second electrochemical cell runs a reverse redox reaction, expelling entropy.

Thermally regenerative ammonia-based battery systems and methods of their use to produce electricity are provided according to aspects described herein in which ammonia is added into an anolyte to charge the battery, producing potential between the electrodes. At the anode, metal corrosion occurs in the ammonia solution to form an ammine complex of the corresponding metal, while reduction of the same metal occurs at the cathode. After the discharge of electrical power produced, ammonia is separated from the anolyte which changes the former anolyte to catholyte, and previous anode to cathode by deposition of the metal. When ammonia is added to the former catholyte to make it as anolyte, the previous cathode becomes the anode. This alternating corrosion/deposition cycle allows the metal of the electrodes to be maintained in closed-loop cycles, and waste heat energy is converted to electricity by regeneration of ammonia, such as by distillation.

A thermo-electro-chemical converter direct heat to electricity engine has a monolithic co-sintered ceramic structure or a monolithic fused polymer structure that contains a working fluid within a continuous closed flow loop. The co-sintered ceramic or fused polymer structure includes a conduit system containing a heat exchanger, a first high density electrochemical cell stack, and a second high density electrochemical cell stack.

A direct heat to electricity engine includes solid state electrodes of an electrochemically active material that has an electrochemical reaction potential that is temperature dependent. The electrodes are configured in combination with electrolyte separators to form membrane electrode assemblies. The membrane electrode assemblies are grouped into pairs, whereby each membrane electrode assembly of a given pair is ionically and electronically interconnected with the other. One membrane electrode assembly of a given pair is coupled to a heat source with the other to a heat sink. One membrane electrode assembly of the pair is electrically discharged while the other is electrically charged, whereby the net and relative charge between the two remains constant because of the electronic and ionic interconnection and the difference in temperature of the membrane electrode assemblies, and thereby voltage, results in net power generation.

A converter includes a working fluid, a housing, a heat sink, a heat source that is at an elevated temperature relative to the heat sink, a first electrochemical cell disposed within the housing, and a micro/nano porous media disposed within the housing. The first electrochemical cell includes a first membrane electrode assembly across which the working fluid is configured to flow. The first membrane electrode assembly includes a first porous electrode and a second porous electrode and at least one ion conductive membrane sandwiched between the first and second porous electrodes. The first electrochemical cell is arranged between the heat source and the heat sink. The working fluid is contained within the micro/nano porous media. The micro/nano porous media is thermally coupled between the heat source and the heat sink, and creates a pressure differential across the first electrochemical cell by transpiration pumping of the working fluid.

A hydride heat engine produces electricity from a heat source, such as a solar heater. A plurality of metal hydride reservoirs are heated by the heating device and a working fluid comprises hydrogen is incrementally move from one metal hydride reservoir to a success metal hydride reservoir. The working fluid is passed, at a high pressure, from the last of the plurality of metal hydride reservoirs to an electro-chemical-expander. The electro-chemical-expander has an anode, a cathode, and an ionomer therebetween. The hydrogen is passed from the anode at high pressure to the cathode at lower pressure and electricity is generated. The solar heater may be a solar water heater and the hot water may heat the metal hydride reservoirs to move the hydrogen. The working fluid may move in a closed loop.

Provided are systems and methods for thermally-regenerative batteries that avoid solid metal dissolution and deposition reactions. A thermoelectrochemical system includes a reactor comprising first and second electrode compartments with a separator interposed between the first and second electrode compartments. The reactor further includes first and second electrodes disposed in the first and second electrode compartments, respectively. The first and second electrode compartments include first and second aqueous electrolyte solutions, respectively. The first electrode compartment, the second electrode compartment, or both include a thermally regenerative ligand and optionally a non-thermally regenerative ligand. The first and second aqueous electrolyte solutions exclude solid metal dissolution and deposition reactants. Also provided are methods of using the thermoelectrochemical systems provided herein.