Electrochemical cell including an additive and method of operating the electrochemical cell

Patent metadata

Field	Value
Publication number	US-2025219155-A1
Application number	US-202419001934-A
Country	US
Kind code	A1
Filing date	Dec 26, 2024
Priority date	Dec 28, 2023
Publication date	Jul 3, 2025
Grant date	—

Abstract

An electrochemical cell including: a first electrode including iron, wherein a density (D) of the iron in the first electrode is greater than 2.11 g/cm3 and less than 7.87 g/cm3, based on a total weight of the iron and a total volume of the first electrode; an alkaline electrolyte; a second electrode; and an additive comprising a metal M, wherein the additive is effective to facilitate oxidation of the iron to Fe3-xMxO4, wherein 0≤x<1, and wherein a specific discharge capacity (Q) of the first electrode in the first discharge plateau is represented by Formula 1:Q>((7.87/D)−1)*352 mAh/gram of iron, based on a total weight of iron in the first electrode  (1).

First claim

1 . An electrochemical cell comprising:
a first electrode comprising iron, wherein a density (D) of the iron in the first electrode is greater than 2.11 g/cm 3 and less than 7.87 g/cm 3 , based on a total weight of the iron and a total volume of the first electrode; an alkaline electrolyte; a second electrode; and an additive comprising a metal M, wherein the additive is effective to facilitate oxidation of the iron to Fe 3-x M x O 4 , wherein 0≤x<1, optionally 0<x<1, and wherein a specific discharge capacity (Q) of the first electrode in a first discharge plateau is represented by Formula 1
Q >((7.87 /D )−1)*352 mAh/gram of iron, based on the total weight of iron in the first electrode  (1).

2 . The electrochemical cell of claim 1 , wherein the iron is not entirely in a form of Fe 3 O 4 .

3 . The electrochemical cell of claim 1 , wherein
the density (D) of the iron in the first electrode is less than 3.74 gram/cm 3 , based on the total weight of the iron and the total volume of the first electrode, the specific discharge capacity (Q) of the first electrode in the first discharge plateau is less than 1280 mAh/gram of iron, based on the total weight of iron in the first electrode, and the specific discharge capacity (Q) of the first electrode in the first discharge plateau is greater than
((7.87 /D )−1)*352 mAh/gram of iron, based on the total weight of iron in the first electrode.

4 . The electrochemical cell of claim 1 , wherein
the density of iron (D) in the first electrode is less than 3.74 gram/cm 3 , based on the total weight of iron and the total volume of the first electrode, and the specific discharge capacity (Q) of the first electrode in the first discharge plateau is less than ((7.87/D)−1)*1158.4 mAh/gram of iron, based on the total weight of iron in the first electrode, and greater than ((7.87/D)−1)*352 mAh/gram of iron, based on the total weight of iron in the first electrode.

5 . The electrochemical cell of claim 1 ,
wherein the additive is in the alkaline electrolyte, the first electrode, or a combination thereof, and wherein the metal M is Sn, Mo, W, Nb, Ta, Ge, Pb, Bi, Sb, Ti, Al, Zn, or a combination thereof, and
optionally wherein when the alkaline electrolyte comprises the additive, a content of the additive in the alkaline electrolyte is 0.1 to 200 millimolar, based on a total volume of the alkaline electrolyte, or
optionally wherein when the first electrode comprises the additive, a content of the additive in the first electrode is 0.5 to 25 weight percent based on a total volume of the first electrode.

6 . The electrochemical cell of claim 1 ,
wherein the specific discharge capacity of the first electrode and based on the weight of iron in the first electrode is at least 90% of a total specific discharge capacity of the first electrode.

7 . The electrochemical cell of claim 1 , wherein the Fe 3-x M x O 4 is disposed in a pore of the first electrode, and wherein the Fe 3-x M x O 4 is reversibly reducible to metallic iron and an M-containing species when M is present upon charging the electrochemical cell.

8 . An electrochemical cell comprising:
a first electrode comprising iron,
wherein a density (D) of the iron in the first electrode is greater than 2.11 g/cm 3 and less than 7.87 g/cm 3 , based on a total weight of iron and a total volume of the first electrode;
wherein the first electrode comprises Fe 3-x M x O 4 , wherein M is a metal and 0≤x<1, optionally 0<x<1;
an alkaline electrolyte; a second electrode; and wherein a specific discharge capacity (Q) of a first electrode in a first discharge plateau is represented by Formula 1
Q >((7.87 /D )−1)*352 mAh/gram of iron, based on the total weight of iron in the first electrode  (1).

9 . The electrochemical cell of claim 8 ,
wherein the M is a metal effective to facilitate oxidation of the iron in the first electrode to Fe 3-x M x O 4 , wherein the metal M is Sn, Mo, W, Nb, Ta, Ge, Pb, Bi, Sb, Ti, Al, Zn, or a combination thereof, and wherein the alkaline electrolyte, the first electrode, or a combination thereof further comprise an additive comprising the M, and
optionally wherein when the alkaline electrolyte comprises the additive, a content of the additive in the alkaline electrolyte is 0.1 to 200 millimolar, based on a total volume of the alkaline electrolyte, or
optionally wherein when the first electrode comprises the additive, a content of the additive in the first electrode is 0.5 to 25 weight percent based on a total volume of the first electrode.

10 . The electrochemical cell of claim 8 , wherein the Fe 3-x M x O 4 is an oxidation product of the iron in the first electrode, formed on discharge of the electrochemical cell.

11 . The electrochemical cell of claim 8 ,
wherein the density of iron (D) in the first electrode is greater than 2.11 g/cm 3 and less than 3.74 gram/cm 3 , based on the total weight of the iron and the total volume of the first electrode, and wherein the specific discharge capacity (Q) of the first electrode in the first discharge plateau, based on the total weight of iron in the first electrode is:
less than 1280 mAh/gram of iron in the first electrode, or
less than ((7.87/D)−1)*1158.4 mAh/gram of iron in the first electrode; and
greater than ((7.87/D)−1)*352 mAh/gram of iron in the first electrode.

12 . The electrochemical cell of claim 8 ,
wherein the specific discharge capacity of the first electrode in the first discharge plateau and based on the weight of iron in the first electrode is at least 90% of a total specific discharge capacity of the first electrode.

13 . The electrochemical cell of claim 8 , wherein the Fe 3-x M x O 4 is disposed in a pore of the first electrode, and wherein the Fe 3-x M x O 4 is reversibly reducible to metallic iron and an M-containing species when M is present upon charging the electrochemical cell.

14 . An electrochemical cell comprising:
a first electrode comprising iron, wherein a density of the iron in the first electrode is less than 2.11 g/cm 3 , based on a total weight of the iron and a total volume of the first electrode; an alkaline electrolyte; a second electrode; and an additive comprising a metal M, wherein the additive is effective to facilitate oxidation of the iron to Fe 3-x M x O 4 , wherein 0≤x<1, optionally 0<x<1, and wherein a specific discharge capacity of the first electrode in the first discharge plateau is greater than 960 mAh/gram of iron, based on the total weight of iron in the first electrode.

15 . The electrochemical cell of claim 14 , wherein the iron is not entirely in a form of Fe 3 O 4 .

16 . The electrochemical cell of claim 14 , wherein the specific discharge capacity of the first electrode in the first discharge plateau is greater than 960 mAh/gram of iron, and less than 1280 mAh/gram of iron, based on the total weight of iron in the first electrode.

17 . The electrochemical cell of claim 14 ,
wherein the additive is in the alkaline electrolyte, the first electrode, or a combination thereof, and wherein the metal M is Sn, Mo, W, Nb, Ta, Ge, Pb, Bi, Sb, Ti, Al, Zn, or a combination thereof, and
optionally wherein when the alkaline electrolyte comprises the additive, a content of the additive in the alkaline electrolyte is 0.1 to 200 millimolar, based on a total volume of the alkaline electrolyte, or
optionally wherein when the first electrode comprises the additive, a content of the additive in the first electrode is 0.5 to 25 weight percent based on a total volume of the first electrode.

Assignees

• Form Energy Inc

Inventors

• Norman Zachariah
• Gibson Michael
• Thompson Annelise
• Nation Leah
• Eisenach Rebecca
• Douair Iskander

Classifications

• H01M12/08

  composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type · CPC title

• H01M4/48

  of inorganic oxides or hydroxides · CPC title

• H01M4/38

  of elements or alloys · CPC title

• H01M10/26 Primary

  Selection of materials as electrolytes · CPC title

• H01M2004/027

  Negative electrodes · CPC title