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US-12620592-B2 - ϵ-VOPO4 cathode production, and applications thereof

US12620592B2US 12620592 B2US12620592 B2US 12620592B2US-12620592-B2

Abstract

A lithium battery with a cathode fabricated using an improved method for slurry formulation and electrode production. The cathode comprises the epsilon polymorph of vanadyl phosphate, ε-VOPO 4 , made from solvothermally synthesized H 2 VOPO 4 , and optimized to reversibly intercalate two Li-ions to reach full theoretical capacity with a coulombic efficiency of 98%. This material adopts a stable 3D tunnel structure and can extract two Li-ions per vanadium ion, giving a theoretical capacity of 305 mAh/g, with an upper charge/discharge plateau at around 4.0 V, and one lower at around 2.5 V. The ε-VOPO4 particles may be modified with niobium (Nb) to improve the cycling stability.

Inventors

  • Krystal Lee
  • Carrie Siu
  • Fengxia Xin
  • M. Stanley Whittingham

Assignees

  • THE RESEARCH FOUNDATION FOR THE STATE UNIVERSITY OF NEW YORK

Dates

Publication Date
20260505
Application Date
20230809

Claims (20)

  1. 1 . A cathode for A lithium battery, comprising: ε-VOPO 4 particles having a dual lithium ion exchange characteristic; wherein the ε-VOPO 4 particles are solvothermally generated and modified to include β-VOPO 4 ; and wherein the cathode has a capacity of at least 260 mAh/g at a discharge rate of C/20.
  2. 2 . The cathode of claim 1 , wherein the cathode has a capacity of at least 275 mAh/g at a discharge rate of C/20.
  3. 3 . The cathode of claim 1 , wherein the cathode has a capacity of at least 285 mAh/g at a discharge rate of C/20.
  4. 4 . The cathode of claim 1 , wherein the modified ε-VOPO 4 particles are modified with niobium.
  5. 5 . The cathode of claim 4 , wherein the cathode niobium concentration exceeds 1.0 mol %.
  6. 6 . The cathode of claim 4 , wherein the cathode niobium concentration exceeds 3.6 mol %.
  7. 7 . The cathode of claim 4 , wherein the cathode niobium concentration exceeds 6.0 mol %.
  8. 8 . A lithium battery, comprising: a cathode formed with modified ε-VOPO 4 particles comprising β-VOPO 4 , having a dual lithium ion exchange characteristic, wherein the modified ε-VOPO 4 particles are solvothermally generated, and wherein the cathode has a capacity of at least 260 mAh/g at a discharge rate of C/20; and an anode.
  9. 9 . The lithium battery of claim 8 , wherein the cathode has a capacity of at least 275 mAh/g at a discharge rate of C/20.
  10. 10 . The lithium battery of claim 8 , wherein the cathode has a capacity of at least 285 mAh/g at a discharge rate of C/20.
  11. 11 . The lithium battery of claim 8 , wherein the solvothermally generated ε-VOPO 4 particles are modified with niobium.
  12. 12 . The lithium battery of claim 11 , wherein the cathode niobium concentration exceeds 1.0 mol %.
  13. 13 . The lithium battery of claim 11 , wherein the cathode niobium concentration exceeds 3.0 mol %.
  14. 14 . The lithium battery of claim 11 , wherein the cathode niobium concentration exceeds 6.0 mol %.
  15. 15 . The lithium battery of claim 8 , wherein the anode is a lithium metal anode.
  16. 16 . A lithium metal battery, comprising: a cathode formed with ε-VOPO 4 particles having a dual lithium ion exchange characteristic, modified to include β-VOPO 4 , wherein the ε-VOPO 4 particles are solvothermally generated, and wherein the cathode has a capacity of at least 260 mAh/g at a discharge rate of C/10; and a lithium metal anode.
  17. 17 . The lithium metal battery of claim 16 , wherein the ε-VOPO 4 particles are modified with niobium.
  18. 18 . The lithium metal battery of claim 17 , wherein the cathode niobium concentration exceeds 1.0 mol %.
  19. 19 . The lithium metal battery of claim 17 , wherein the cathode niobium concentration exceeds 3.6 mol %.
  20. 20 . The lithium metal battery of claim 17 , wherein the cathode niobium concentration exceeds 6.0 mol %.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present invention is a Continuation-In-Part of U.S. patent application Ser. No. 18/354,493, Filed Jul. 18, 2023, now pending, which is a Continuation of U.S. patent application Ser. No. 17/670,470, filed Feb. 13, 2022, now U.S. Pat. No. 11,715,929, issued Aug. 1, 2023, which is a Division of U.S. patent application Ser. No. 16/291,617, filed Mar. 4, 2019, now U.S. Pat. No. 11,251,430, issued Feb. 15, 2022, which is a Non-Provisional of and claims benefit of priority from U.S. Patent Application No. 62/638,893, filed Mar. 5, 2018, each of which is expressly incorporated herein in its entirety by reference, and this application is a Continuation-In-Part of U.S. patent application Ser. No. 18/030,868, filed Apr. 7, 2023, which is a National Stage Application of U.S. PCT Application PCT/US2021/055328, filed Oct. 16, 2021, which claims the benefit of priority from U.S. Patent Application 63/092,755, filed Oct. 16, 2020, each of which is expressly incorporated herein in its entirety by reference. STATEMENT OF FEDERALLY FUNDED RESEARCH This invention was made with government support under contract DE-SC0012583 awarded by the Department of Energy and contract DE-EE0007765 awarded by the Department of Energy. The government has certain rights in the invention. TECHNICAL FIELD The present invention relates to a rechargeable lithium battery with an improved ε-VOPO4 cathode, and applications thereof. BACKGROUND Lithium-ion batteries dominate the lithium battery market. These batteries use intercalation electrodes, which were discovered by Dr. M. Stanley Whittingham in the 1970s, and Dr. Whittingham patented the world's first lithium metal battery in 1977. While present-day lithium batteries work well, lithium batteries having improved cathodes and improved anodes are still needed, as well as methods for producing these improved cathodes and improved anodes. SUMMARY The embodiments featured herein include lithium batteries having improved cathodes, and methods for producing these improved cathodes. In an embodiment, a lithium battery is presented in which a vanadyl phosphates ε-VOPO4 cathode is used that can achieve multi-electron storage. Vanadyl phosphates in general have low intrinsic conductivity. A high efficiency battery cathode has low electrical resistance. In embodiments, to improve conductivity, the cathode material is preferably nanosized, and coated with particles of a low activation energy conductive material, such as graphene or carbon nanotubes. This cathode utilizes the two redox couples of vanadium cation (i.e., V5+/V4+, V4+/V3+) to permit more than one lithium ion to be stored in the unit structure per vanadium ion. The involvement of the multiple redox processes of vanadium is reflected by the well separated high voltage plateau region at ˜3.8 V and low voltage plateau region at ˜2 V. The two-electron redox property of vanadium results in a theoretical capacity of 305 mAh/g. In practical, maximum discharge capacity of over 300 mAh/g have been obtained within the voltage region of 1.3-4.5 V vs. Li/Li+, which is over 90% of the theoretical value. In an embodiment, in addition to ε-VOPO4 material, the cathode may further contain any cathode material suitable for lithium-ion insertion and release. Suitable auxiliary materials may include phosphate-based materials such as FePO4, VPO4F, V2(PO4)2F3, FePO4F, and V2(PO4)3; oxides such as CoO2, orthorhombic MnO2, layered iron oxides FeO2, chromium oxide CrO2, layered Ni0.5Mn0.5O2, and V6O15 nanorods; layer sulfides such as TiS2; perovskite transition metal fluorides, or a mixture thereof. The epsilon polymorph of vanadyl phosphate, ε-VOPO4, made from the hydrothermally or more generally, solvothermally synthesized H2VOPO4, is a cathode material for lithium-ion batteries that has been optimized to reversibly intercalate two Li-ions to reach the full theoretical capacity with a coulombic efficiency of 98%. This material adopts a stable 3D tunnel structure and can extract two Li-ions per vanadium ion, giving a theoretical capacity of 305 mAh/g, with an upper charge/discharge plateau at around 4.0 V, and one lower at around 2.5 V. As ε-VOPO4 is capable of reversibly intercalating more than one lithium ion into the structure, it stores and delivers more energy than current batteries in the market. Compared to LiFePO4, ε-VOPO4 has a higher electronic conductivity and higher energy density with the insertion of one Li-ion, 159 mAh/g at 4.0 V vs 170 mAh/g at 3.45 V. Overall, ε-VOPO4 is a great candidate for next generation high energy Li-ion batteries. The nano-sized ε-VOPO4 particles demonstrate enhanced electrochemistry and cyclability for potential applications in lithium batteries. In an embodiment of the present invention, a high energy density cathode active material is provided for use in a lithium battery, using ε-VOPO4 as an active material, and which comprises a conductivity enhancer comprising graphene or carbon na