Apparatus, systems and methods for high efficiency metal particle regeneration

1. A regenerator stack comprising a plurality of regenerator cells, each regenerator cell for regenerating metallic particles, and comprising:

a housing for containing a quantity of electrolyte;

an anode;

a cathode for deposition of the metallic particles;

a cavity at least partially defined by the housing, the cathode and the anode;

an inlet port for supplying electrolyte to the cell, the inlet port in fluid communication with the cavity; and

an outlet port for expelling electrolyte, particles and/or gas from the cell, the outlet port in fluid communication with the cavity;

wherein the plurality of regenerator cells are configured to enable fluid isolation between cavities of the regenerator cells, whereby an air lock is established as between the cavities of the regenerator cells;

wherein the regenerator stack comprises a plurality of regenerator cells; and

wherein the cathode of one regenerator cell is in physical contact with, and electrically connected to, the anode of an adjacent regenerator cell to provide a bipolar electrode.

2. A regenerator stack according to claim 1 wherein for each regenerator cell the outlet port is located above a level of the electrolyte in the cavity and is capable of forming an airlock to prevent draining of electrolyte.

3. A regenerator stack according to claim 1 wherein for each regenerator cell the inlet port is located above the level of the electrolyte in the cavity and is capable of forming an airlock to prevent draining of electrolyte.

4. A regenerator stack according to claim 1 wherein for each regenerator cell the inlet port is located below a level of the electrolyte in the cavity, wherein the inlet port is rotatable and wherein a rotation means for rotating the inlet port is selected from the group consisting of magnets, a fluid pressurizer, and a motor.

5. A regenerator stack according to claim 4 wherein for each regenerator cell the inlet port comprises a radially extending arm, the arm comprising at least one opening facing a surface of the cathode, the at least one opening in fluid communication with a manifold outlet; wherein:

optionally the at least one opening comprises a plurality of holes spaced apart along the arm, each of the plurality of holes in fluid communication with the inlet port,

optionally each of the plurality of holes has a width or diameter in the range of 0.1 mm to 3 mm and is spaced apart by 0.5 mm to 3 mm; and

optionally the at least one opening comprises an open channel extending along the arm, the channel in fluid communication with the inlet port.

6. A regenerator stack according to claim 5 wherein, for each regenerator cell an inner surface of the at least one opening of the arm is lined with a metal capable of galvanic corrosion of the metallic particles; wherein the metal is optionally stainless steel or platinum.

7. A regenerator stack according to claim 1 wherein, for each regenerator cell:

the cathode and the anode are substantially planar;

the cathode has a surface roughness RMS of 0.05 micron to 1 micron;

an outer edge of the cathode comprises a nonconductive and nonporous coating comprising oxides; or

a ratio of a distance between the anode and the cathode relative to the height of the anode and the cathode is in the range of 1:1 to 1:40.

8. A regenerator stack according to claim 1 wherein, for each regenerator cell the cathode comprises magnesium, chromium, niobium, zirconium, titanium, hafnium, tantalum, yttrium, strontium, calcium, scandium, tungsten, or an alloy of those metals with any other metals; or wherein the anode comprises nickel, a nickel alloy, manganese, manganese based oxides, perovskites, spinel structures or oxide and layered hydroxides.

9. A regenerator stack according to claim 1 , wherein, each regenerator cell comprises an auxiliary electrode located within the cavity, wherein the auxiliary electrode is spaced apart from the cathode and the anode, wherein the auxiliary electrode is capable of establishing ionic conduction with the cathode or the anode through an aqueous electrolyte, wherein the auxiliary electrode optionally comprises platinum, gold, nickel, iron, tungsten or any metals or any alloys of metals with hydrogen evolution potential less than or equal to that of iron.

10. A regenerator stack according to claim 1 , further comprising an inlet manifold capable of distributing electrolyte to a plurality of inlet ports and an outlet manifold capable of expelling electrolyte, particles and/or gas from a plurality of outlet ports; wherein the regenerator cells are optionally connected in series.

11. A regenerator stack according to claim 1 further comprising a plurality of connectors connecting a plurality of bipolar electrodes to enable the establishment of a reverse circuit scheme differentiated from a forward circuit scheme.

12. A regenerator system comprising a regenerator stack according to claim 1 and an intermediate tank in fluid communication with the cavities of the regenerator cells of the regenerator stack.