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US-12626900-B2 - Elastic and stretchable gel polymer electrolyte and methods of making the same

US12626900B2US 12626900 B2US12626900 B2US 12626900B2US-12626900-B2

Abstract

The present disclosure relates generally to a coated electrode for use in preparation of lithium ion batteries and methods of preparing such. More particularly, the present disclosure relates to a polymer coating composition for coating electrodes of the lithium ion batteries (LIBs). The polymer coating composition comprises a polyurethane gel polymer electrolyte (GPE) formed by a reaction of an isocyanate and a polyol.

Inventors

  • Alan Edward Goliaszewski
  • Shufu Peng
  • Donghai Wang
  • Jiangxuan Song
  • Qingquan HUANG
  • Kelly Anne Brush

Assignees

  • HERCULES LLC

Dates

Publication Date
20260512
Application Date
20230629

Claims (16)

  1. 1 . A method of making a coated electrode for use in preparation of a lithium ion battery comprising: (i) combining an electrode active material, a binder composition, and a conductive agent to form a slurry; (ii) applying the slurry to a current collector to form a coated current collector comprising a slurry layer on the current collector; (iii) drying the slurry layer on the coated current collector to form a film on the current collector, wherein the electrode comprises the film and the current collector; (iv) applying a polymer coating composition in a solvent to the electrode to form a coated electrode having an outer surface substantially covered by the polymer coating composition, wherein the polymer coating composition is solution-coated on the electrode; and (v) evaporating the solvent from the polymer coating composition to form a polyurethane gel polymer electrolyte coating on the electrode, wherein the polyurethane gel polymer electrolyte comprises a polyurethane formed by a reaction comprising (i) an isocyanate and (ii) a polyol, wherein a molar ratio of the polyol to the isocyanate is in a range of from about 1.0:1.2 to about 1.0:2.0; wherein the isocyanate is an aromatic diisocyanate and the polyol is a polyether polyol; wherein the solvent is selected from the group consisting of N, N-dimethylacetamide (DMAc), tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), tetramethylsilane (TMS), and dimethylformamide (DMF).
  2. 2 . The method of claim 1 , wherein a mass ratio of the electrode active material to the conductive agent to the binder composition is about 8:1:1.
  3. 3 . The method of claim 1 , wherein the polymer coating composition has a mass loading in a range of from about 0.1 mg/cm 2 to about 0.9 mg/cm 2 .
  4. 4 . The method of claim 1 , wherein the polyurethane is present in the polymer coating composition in a range of from about 1% to about 25% by weight.
  5. 5 . The method of claim 1 , wherein the aromatic isocyanate is 4,4′-methylenebis(phenyl isocyanate).
  6. 6 . The method of claim 1 , wherein the polyether polyol is poly(tetrahydrofuran).
  7. 7 . The method of claim 1 , wherein the molar ratio of the polyol to the isocyanate is about 1.0:1.5.
  8. 8 . The method of claim 1 , wherein the polyol has a number average molecular weight in a range of from about 1,000 to about 3,500 Daltons.
  9. 9 . The method of claim 8 , wherein the polyol has a number average molecular weight of about 1,570 Daltons.
  10. 10 . The method of claim 1 , wherein the reaction is substantially free of ethylene diamine.
  11. 11 . The method of claim 1 , wherein the electrode active material is an anode active material.
  12. 12 . The method of claim 11 , wherein the anode active material is selected from the group consisting of (A) a carbonaceous material, (B) a silicon-based alloy, (C) a complex compound comprising a carbonaceous material and a metal selected from the group consisting of Al, Ag, Bi, In, Ge, Mg, Pb, Si, Sn, Ti, and combinations thereof, (D) a lithium complex metal oxide, (E) a lithium-containing nitride, and (F) combinations of components comprising items (A)-(E).
  13. 13 . The method of claim 12 , wherein the anode active material comprises graphite and silicon oxide, wherein a weight ratio of the graphite to the silicon oxide is in a range of from about 99:1 to about 1:99.
  14. 14 . The method of claim 1 , wherein the binder composition is substantially free of polyurethane.
  15. 15 . The method of claim 1 , wherein the conductive agent is selected from the group consisting of conductive carbon, carbon nanotubes, carbon black, carbon fiber, graphite, graphene, and combinations thereof.
  16. 16 . The method of claim 1 , wherein the current collector is selected from the group consisting of aluminum, carbon, copper, stainless steel, nickel, zinc, silver, and combinations thereof.

Description

RELATED APPLICATIONS This application claims priority to U.S. patent application Ser. No. 16/753,687, filed on Apr. 3, 2020, which is a National Stage Entry of PCT/US2018/054105, filed on Oct. 3, 2018, which claims priority to U.S. Provisional Application No. 62/568,224, filed on Oct. 4, 2017 and 62/571,681, filed on Oct. 12, 2017, all entitled Elastic and Stretchable Gel Polymer Electrolyte, which are incorporated herein in their entirety. FIELD The presently disclosed and/or claimed inventive process(es), procedure(s), method(s), product(s), result(s), and/or concept(s) (collectively referred to hereinafter as the “present disclosure”) relates generally to a coated electrode for use in lithium ion batteries and methods of preparing such. More particularly, but not by way of limitation, the present disclosure relates to a polymer coating composition used for coating electrodes of lithium ion batteries (LIBs). The polymer coating composition comprises a polyurethane gel polymer electrolyte (GPE) formed by a reaction of an isocyanate and a polyol. Additionally, the present disclosure relates generally to the compositions and methods of making electrodes, in particular but without limitation, anodes, with the polymer coating composition comprising the polyurethane GPE. BACKGROUND Lithium ion batteries (LIBs) are used in many products including medical devices, electric cars, airplanes, and most notably, consumer products such as laptop computers, cell phones, and cameras. Due to their high energy densities, high operating voltages, and low-self discharges, lithium ion batteries have overtaken the secondary battery market and continue to find new uses in products and developing industries. Generally, a lithium ion batteries (LIB) comprises an anode, a cathode, and an electrolyte material such as an organic solvent containing a lithium salt. More specifically, the anode and cathode (collectively, “electrodes”) are formed by mixing either an anode active material or a cathode active material with a binder and a solvent to form a paste or slurry which is then coated and dried on a current collector (e.g., aluminum or copper), to form a film on the current collector. The anodes and cathodes are then layered or coiled prior to being housed in a pressurized casing containing an electrolyte material, which all together forms the LIB. During charging and discharging of LIBs, significant volume changes in the electrodes may occur. Such cycling volume changes generate a large strain on the electrodes resulting in electrode structural damages and deformations, such as pulverization of the electrode active materials. Volume changes also increase accumulated growth of the solid electrolyte interface (SEI) layer, which is a passivation layer formed by chemical and electrochemical reaction of the liquid electrolyte. The formation of an SEI layer in an LIB is unavoidable, and, when stabilized, essential to accommodate the large volume change of electrodes. However, when the electrodes experience large volume changes the SEI layer is destabilized and overgrowth can occur. The amount of electrode volume change depends largely upon the type of active material utilized in the electrode. Silicon has recently come to the forefront as a promising anode active material for LIBs. See, for example, B. Lestriez et al., On the Binding Mechanism of CMC in Si Negative Electrodes for Li-Ion Batteries, Electrochemistry Communications, vol. 9, 2801-2806 (2007), which is hereby incorporated herein by reference in its entirety. Silicon is a promising anode active material because: (a) its high theoretical specific capacity of 4200 mAhg−1 for Li4.4Si; (b) its high areal capacity with the ability to pair with commercial cathodes; (c) its low electrochemical potential between 0 and 0.4 V versus Li/Li+; and (d) its small initial irreversible capacity compared with other metal- or alloy-based anode materials. See, B. Koo et al., A Highly Cross-linked Polymeric Binder for High-Performance Silicon Negative Electrodes in Lithium Ion Batteries, Angew. Chem. Int. Ed. 2012, 51, 8762-8767, hereby incorporated herein by reference in its entirety. It has been found that a specific capacity of about 600 mAhg−1 can be achieved by mixing graphite with silicon oxide (SiOX) and conductive carbon at a weight ratio of about 0.795/0.163/0.042 and, alternatively, a specific capacity of about 450 mAhg−1 can be achieved by mixing graphite with silicon oxide at a weight ratio of about 92 to 5, both of which increase the specific capacity of the anode material above the 340 mAhg−1 associated with graphite independent of any other electrode active material. Silicon has been known, however, to undergo large degrees of expansion and contraction during charging and discharging (i.e., the volume changes discussed hereinabove), which can degrade a battery's capacity and overall performance. In each battery cycle, as the electrode active material's silicon particles undergo exp