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US-12620594-B1 - Secondary particle composite Group IVA materials

US12620594B1US 12620594 B1US12620594 B1US 12620594B1US-12620594-B1

Abstract

Exemplary secondary particles may include a porous polymer matrix comprising polyacrylonitrile (PAN) and polypyrrole (PPy), and a plurality of submicron-sized primary particles dispersed in the porous polymer matrix. The plurality of submicron-sized primary particles may comprise at least one of: carbon (C), silicon (Si), germanium (Ge), tin (Sn), or an alloy of a Group IVA element.

Inventors

  • Jeff A. Norris
  • Timothy D. Newbound
  • Anton Kornberg

Assignees

  • Kratos LLC

Dates

Publication Date
20260505
Application Date
20230828

Claims (16)

  1. 1 . A secondary particle comprising: a porous polymer matrix comprising a polyacrylonitrile (PAN)-polypyrrole (PPy) composite, where nitrile groups of PAN are hydrogen bonded to PPy as represented by formula (I) or formula (II), where n is a number of repeating units of PPy and m is a number of repeating units of PAN: at least 1 wt % and no greater than 88 wt % of submicron-sized primary particles dispersed in the porous polymer matrix, the submicron-sized primary particles comprising at least one of: carbon (C), silicon (Si), germanium (Ge), tin (Sn), or an alloy of a Group IVA element, the secondary particle having a Dv50 diameter no less than 3 μm and no greater than 12 μm.
  2. 2 . The secondary particle according to claim 1 , wherein a PAN backbone comprises six-member rings and the PAN-PPy composite is represented by formula (II); and wherein more than 50 wt % of the PPy in the secondary particle is bonded to the PAN.
  3. 3 . The secondary particle according to claim 1 , wherein an average size distribution (D v 50) of the primary particle ranges between 20-225 nm; and wherein the submicron-sized primary particle comprises 15-88% of a total weight of the secondary particle.
  4. 4 . The secondary particle according to claim 1 , wherein the porous polymer matrix or a surface of the secondary particle further comprises polyacrylic acid (PAA); and wherein the PAA comprises between 0.5 wt % and 5 wt % of the secondary particle.
  5. 5 . The secondary particle according to claim 1 , wherein the secondary particle has an elastic recovery percentage between 13% and 17%.
  6. 6 . The secondary particle according to claim 1 , wherein the secondary particle has a hardness no less than 150 MPa and no greater than 3000 MPa.
  7. 7 . The secondary particle according to claim 1 , wherein the secondary particle has an elastic recovery no less than 200 MPa and no greater than 42,000 MPa.
  8. 8 . The secondary particle according to claim 1 , wherein the secondary particle has a conductivity between 10 −3 S×cm −1 and 10 −6 S×cm −1 .
  9. 9 . The secondary particle according to claim 1 , wherein the secondary particle has an elastic modulus no less than 18,000 MPa and no greater than 22,000 MPa.
  10. 10 . The secondary particle according to claim 1 , wherein the submicron-sized primary particles further comprises a chemically-bonded surface modifier, wherein the chemically-bonded surface modifier is derived from acrylonitrile, pyrrole, polypyrrole, polyacrylonitrile, perfluoroalkylethylenes, acetylene, ethylene, 1-alkenes C12 or less, or 1-alkynes (C12 or less).
  11. 11 . The secondary particle according to claim 1 , further comprising a plurality of bridging segments dispersed within the porous polymer matrix, the plurality of bridging segments is derived from a diene compound, a dinitrile compound, and/or a diazo compound.
  12. 12 . The secondary particle according to claim 1 , further comprising a polymer layer on an exterior surface of the secondary particle, wherein the polymer layer comprises polyacrylonitrile, polyacrylic acid, polypyrrole, cross-linked polyacrylonitrile, cross-linked polypyrrole, or combinations thereof.
  13. 13 . The secondary particle according to claim 12 , wherein the polymer layer comprises a derivative of tetrafluoroethylene monomer.
  14. 14 . The secondary particle according to claim 1 , the porous polymer matrix comprising a plurality of fibral strands linking portions of the porous polymer matrix and defining a plurality of crazes.
  15. 15 . The secondary particle according to claim 1 , wherein an FTIR spectrum of the porous polymer matrix has a —C≡N stretching frequency between 2240.75 cm −1 and 2239.0 cm −1 .
  16. 16 . A negative electrode, comprising: active material comprising the secondary particle according to claim 1 ; binder; and conductive material.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is related to and claims the priority benefit of U.S. Provisional Patent Application No. 63/373,656, filed Aug. 26, 2022, and U.S. Provisional Patent Application No. 63/452,993, filed Mar. 17, 2023, the entire contents both of which are incorporated herein by reference. FIELD The present disclosure relates to particulate compositions and their use in, e.g., battery applications. INTRODUCTION High-capacity negative electrodes used in lithium-ion batteries include active materials that form alloys with lithium in contrast to conventional graphite active materials that accommodate lithium by intercalation. Intercalation is a process by which a mobile ion or molecule is reversibly incorporated into vacant sites in a crystal lattice. The crystal lattice structure of the active intercalation material has a fixed volume and limits active sites that accommodate the mobile ions. Fully charged with lithium, graphite has a theoretical gravimetric capacity of 372 mAh/g, while an alloying active material such as silicon can have an order of magnitude higher theoretical capacity (4,200 mAh/g for silicon). Widespread use of alloying active materials such as silicon has been limited in commercial lithium-ion batteries (LIBs) because of inherent properties that silicon and other lithium-active metal alloys possess that lead to rapid fade in reversible capacity upon undergoing multiple charge/discharge cycles. A significant problem is the volume expansion between the charged and discharged states. Swelling of silicon particles by as much as 400% from fully discharged to fully charged states can cause mechanical degradation of the SEI (solid electrolyte interphase) barrier formed at the interface where electrochemical reduction of lithium ions takes place as they migrate towards and into the active materials. Disruption of SEI causes cracking and subsequent reforming more SEI until excessive SEI impedes ion conduction through the barrier. Mechanical stress can also cause silicon particles to become pulverized, unearthing more surface area around which SEI must be formed. Furthermore, SEI formation consumes active lithium in the cell and leads to loss of electrical contacts. Because electrical conductivity is a fundamental property that the electrodes in and electrochemical cell must possess, materials that allow electron mobility are required. Inorganic carbon such as carbon black or carbon nanotubes are often used to enhance electrical conductivity. However, electrically conductive polymers can also serve as conductive agents while also providing desirable mechanical properties to the matrix surrounding the lithium-active materials. The most widely used method of preparing intrinsically conductive polymers, such as polypyrrole (PPy), polyfluorene (PF), or polyaniline (PANI), is chemical oxidative polymerization. This process is carried out in an acidic aqueous medium in the presence of an oxidating agent, such as ammonium persulfate (APS) or ferric chloride (FeCl3), with the intermediate formation of a complex of a monomer molecule with a dopant. The bulk electrical conductivity and mechanical properties of these polymers vary depending on their monomeric nature and the way of doping. In addition, the properties largely depend on the sub-micro-level and nano-level morphology of a polymer. The micro-level morphology is the geometry and parameters of an arrangement of the individual polymer fibers, such as fiber length and packing density. The nano-level morphology normally means the way the individual polymer chains are packed within the fiber's volume. An individual fiber consists of a highly conductive crystal core and a weakly conductive amorphous periphery. These structures are determined by numerous synthetic conditions such as the choice of a dopant, the viscosity and acidity of the reaction mixture, the medium of the emulsion, the choice and amount of oxidating agent, the temperature and duration of the reaction (these two factors are related), and the intensity of agitation. The doping fraction is needed not only to make the polymer chains conductive; it also enables adjustment of the polymer's mechanical properties, solvent dispersibility, and chemical resistance. Additionally, the dopant chemical structure can be designed in such a way as to ensure chemical or thermodynamic interaction with the surrounding materials, such as other matrix polymers, outer shell materials, and polymer electrolytes. Another important aspect of conductivity for metal ion battery electrodes is ion conductivity. Polyacrylonitrile is a very good ion conductor, but it is not intrinsically electrically conductive. The PAN polymer does not require a dopant. The helical conformation of PAN chains ensures the lowest energy of the cyano group units due to their weak repulsion, which makes the chains electrically insulative. SUMMARY Disclosed herein is an approach to surround Group IV