LITHIUM SULFUR BATTERIES AND ELECTROLYTES AND SULFUR CATHODES THEREOF

• US 20150214555A1
• Filed: 03/13/2015
• Published: 07/30/2015
• Est. Priority Date: 11/15/2011
• Status: Active Grant

• Current Assignee: PolyPlus Battery Company
• Original Assignee: PolyPlus Battery Company
• Inventors: Visco, Steven J., Goncharenko, Nikolay, Nimon, Vitaliy, Petrov, Alexei, Nimon, Yevgeniy S., De Jonghe, Lutgard C., Katz, Bruce D., Loginova, Valentina
• Granted Patent: US 9,660,265 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01M 10/36 Accumulators not provided for in groups H01M10/05-H01M10/34
• CPC Class Codes: H01M 2300/0002 Aqueous electrolytes
• CPC Class Codes: H01M 2300/0014 Alkaline electrolytes
• CPC Class Codes: H01M 2300/0037 Mixture of solvents
• CPC Class Codes: H01M 4/38 of elements or alloys
• CPC Class Codes: H01M 4/382 Lithium H01M4/405 takes precedence
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: H01M 4/405 Alloys based on lithium
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/5815 Sulfides
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 4/661 Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: H01M 4/663 containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
• CPC Class Codes: H01M 4/667 in the form of layers, e.g. coatings
• CPC Class Codes: H01M 4/74 Meshes or woven material; Expanded metal
• CPC Class Codes: H01M 4/806 Nonwoven fibrous fabric containing only fibres
• CPC Class Codes: H01M 4/808 Foamed, spongy materials
• CPC Class Codes: H01M 50/77 with external circulating path
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Lithium sulfur battery cells that use water as an electrolyte solvent provide significant cost reductions. Electrolytes for the battery cells may include water solvent for maintaining electroactive sulfur species in solution during cell discharge and a sufficient amount of a cycle life-enhancing compound that facilitates charging at the cathode. The combination of these two components enhances one or more of the following cell attributes: energy density, power density and cycle life. For instance, in applications where cost per Watt-Hour (Wh) is paramount, such as grid storage and traction applications, the use of an aqueous electrolyte in combination with inexpensive sulfur as the cathode active material can be a key enabler for the utility and automotive industries, for example, providing a cost effective and compact solution for load leveling, electric vehicles and renewable energy storage. Sulfur cathodes, and methods of fabricating lithium sulfur cells, in particular for loading lithium sulfide into the cathode structures, provide further advantages.

Claims

1. An aqueous lithium sulfur battery cell, comprising:

an anode structure comprising a lithium electroactive material;

a cathode comprising a solid electron transfer medium;

an aqueous electrolyte solution comprising an aqueous solvent system and electroactive sulfur species dissolved therein, the aqueous solvent system comprising water solvent for maintaining electroactive sulfur species in solution during cell discharge and a sufficient amount of a cycle life enhancing compound, that facilitates charging at the cathode;

wherein the aqueous electrolyte solution is in electron transfer contact with the cathode but isolated from direct contact with the lithium electroactive material.

2. The aqueous lithium sulfur battery cell of claim 1, wherein the water serves as a reactive solvent for maintaining electroactive sulfur species in solution during cell discharge.

3. The aqueous lithium sulfur battery cell of claim 1, wherein the aqueous electrolyte solution has an active stoichiometric ratio represented by the chemical formula Li₂S_x, with x having a value between 1 and 7.

4. The aqueous lithium sulfur battery cell of claim 3, wherein the cycle life enhancing compound is present in an amount sufficient to support an aqueous electrolyte solution having an active stoichiometric ratio represented by the chemical formula Li₂S_x, wherein x is greater than 5.

32. The aqueous lithium sulfur battery cell of claim 1, wherein the cycle life enhancing compound is an organic compound.

38. The aqueous lithium sulfur battery cell of claim 32, wherein the organic compound is protic nitrogen containing organic compound.

45. The aqueous lithium sulfur battery cell of claim 32, wherein the organic compound is a primary amine.

46. The aqueous lithium sulfur battery cell of claim 32, wherein the organic compound is a secondary amine.

47. The aqueous lithium sulfur battery cell of claim 32, wherein the organic compound is a tertiary amine.

48. The aqueous lithium sulfur battery cell of claim 32, wherein the organic compound is represented by the general formula:

99. The aqueous lithium sulfur battery cell of claim 1, wherein the cycle life enhancing compound is ammonia.

100. The aqueous lithium sulfur battery cell of claim 99, wherein the amount of ammonia in the aqueous solvent is greater than 5% (m/m).

101. The aqueous lithium sulfur battery cell of claim 99, wherein the amount of ammonia in the aqueous solvent is between 5 to 35% (m/m).

102. The aqueous lithium sulfur battery cell of claim 99, wherein the amount of ammonia in the aqueous solvent is between 14 to 33% (m/m).

109. The aqueous lithium sulfur battery cell of claim 99, wherein the pH of the electrolyte absent the ammonia is greater than 12.

110. The aqueous lithium sulfur battery cell of claim 1, wherein the volume percent of water in the aqueous solvent system is at least 10%.

113. The aqueous lithium sulfur battery cell of claim 1, wherein the cell is a secondary battery.

114. The aqueous lithium sulfur battery cell of claim 32, wherein the amount of said organic compound dissolved in the electrolyte is sufficient to yield a cell whereby the total capacity is provided by dissolved active sulfur species, and the delivered capacity of said dissolved sulfur species corresponds to a value that is greater than 700 mAh/gram of dissolved sulfur over at least 2 cycles.

116. The aqueous lithium sulfur battery cell of claim 1, wherein the aqueous solvent system provides a medium for twofold solvolysis of electroactive sulfur species, a firstfold solvolysis taking place during discharge and a secondfold solvolysis taking place during charge, the water serving to solubilze, via hydrolysis, active sulfur species on discharge and the cycle life enhancing compound serving as a reactive solvent for solubilizing electroactive sulfur species on charge.

128. The aqueous lithium sulfur battery cell of claim 116, wherein the aqueous electrolyte solution has an active stoichiometric ratio of greater than 5.

5-31. -31. (canceled)

33-37. -37. (canceled)

39-44. -44. (canceled)

49-98. -98. (canceled)

103-108. -108. (canceled)

111-112. -112. (canceled)

115. (canceled)

117-127. -127. (canceled)

129-144. -144. (canceled)