KR-102963588-B1 - Safe and extended operating voltage zinc-ion battery engineered by a gel-polymer/ionic-liquid electrolyte and water molecules pre-intercalated sheet-like V2O5 cathode

Abstract

One embodiment of the present invention provides a cathode for a zinc ion battery, an electrolyte, and a zinc ion battery comprising the same. The cathode for a zinc ion battery according to one embodiment of the present invention has a high diffusion coefficient compared to conventional V₂O₅ and facilitates reversible insertion/extraction, and the electrolyte used therein reduces dendrite formation, cathode leaching, and unnecessary side reactions, thereby providing a zinc ion battery having high capacity, discharge voltage, rate capability, and long-term stability.

Inventors

• 심재진
• 데이바시가마니란지트쿠마르

Assignees

• 영남대학교 산학협력단

Dates

Publication Date

20260511

Application Date

20230830

Claims (7)

1. A zinc ion battery comprising: a cathode comprising a plurality of sheet-like layers of vanadium pentoxide (V2O5) and a plurality of water molecules preintercalated in the plurality of layers of vanadium pentoxide (V2O5); an anode comprising zinc (Zn); and a gel polymer electrolyte formed between the cathode and the anode. The anode has an s- V₂O₅ · nH₂O structure in which n water molecules are included per vanadium pentoxide unit of the vanadium pentoxide ( V₂O₅ ) layer, and n is a real number from 0.5 to 0.6. The above polymer electrolyte comprises PVDF-HFP (poly(vinylidene fluoride-co-hexafluoropropylene)), EMIBF4 (1-ethyl-3-methylimidazolium tetrafluoroborate), and Zn(OTf) 2 (zinc trifluoromethanesulfonate), and A zinc ion battery characterized in that the above polymer electrolyte is a non-aqueous electrolyte that does not contain water, and excludes the participation of hydrogen ions (H+) in the reaction during discharge and provides a discharge voltage through the reversible insertion of zinc ions (Zn 2+ ).
2. delete
3. In paragraph 1, A zinc ion battery characterized in that the thickness of the vanadium pentoxide ( V₂O₅ ) layer is 150 to 200 nm.
4. In paragraph 1, A zinc ion battery characterized in that the ionic liquid in the above-mentioned polymer electrolyte acts as a cushion to promote the transport of zinc ions within the gel.
5. In paragraph 1, A zinc ion battery characterized in that the anode has a higher ion diffusion coefficient compared to conventional anode materials due to the aforementioned multiple pre-inserted water molecules.
6. In paragraph 1, A zinc ion battery characterized in that the anode forms a sheet structure through the oxidation of a peroxo complex formed by the reaction of vanadium pentoxide and hydrogen peroxide and the freeze-drying of the gel decomposition product.
7. In paragraph 1, A zinc ion battery characterized by the formation of zinc plating on the surface of the cathode by the above polymer electrolyte, thereby suppressing the formation of dendrites.

Description

Safe and extended operating voltage zinc-ion battery engineered by a gel-polymer/ionic-liquid electrolyte and water molecules pre-intercalated sheet-like V2O5 cathode The present invention relates to a zinc ion battery, and more specifically , to a zinc ion battery comprising a gel-polymer/ionic-liquid electrolyte and a pre-intercalated vanadium pentoxide ( V₂O₅ ) cathode (reduction electrode). Battery technology based on rechargeable organic electrolytes holds indispensable importance in modern society. However, today, there are problems associated with the serious ecological and environmental impacts that result from the disposal of these batteries. Currently, lithium-ion batteries (LIBs) are widely used in various fields such as mobile electronic devices, implantable medical devices, grid-level storage applications, and electric vehicles, and this appears to be somewhat dependent. Nevertheless, they are still used in the development of effective grid storage systems due to the chemical reactivity of electrolytes composed of metallic lithium, sodium, and organic carbonate esters, which limits the environmental friendliness and safety of the batteries. Recently, aqueous rechargeable batteries have been gaining attention as an alternative to organic solvent-based electrolytes to overcome these drawbacks. Water electrolytes offer higher ionic conductivity compared to non-water electrolytes and possess advantages such as high capacity and speed, as well as being safe, economical, easy to handle, and environmentally friendly. Among them, aqueous zinc-ion batteries (ZIBs) are particularly attractive alternatives. When zinc metal is used as the cathode, it has a redox potential of 0.76 V and a theoretical capacity of 819 mAh/g, which is higher than the volumetric capacity of lithium (5845 vs 2046 mAh/ cm³ ). Furthermore, zinc has the advantage of being an inherently safe material, as it is widely found on the Earth's surface, stable in air, mass-producible, non-toxic, and exists in harmony with water. However, the lack of reversibility of Zn metal in alkaline media reduces long-term durability and Coulomb efficiency, and aqueous electrolytes have the problem of continuous side reactions with water molecules and dendrite formation during the continuous zinc plating/removal process. On the other hand, neutral or weakly acidic electrolytes of ZIB minimize dendrite formation on the zinc anode surface but have the problem of potentially causing dissolution of the cathode material. Recently, solid or gel polymer electrolyte (GPE) separators have garnered significant interest in the fields of fuel cells, supercapacitors, and batteries. Various studies on these materials are ongoing because GPEs reduce the potential for Zn anode dendrites, electrolyte leakage, and cathode re -dissolution in V₂O₅ of ZIBs, while increasing the potential window and thermal stability. Meanwhile, finding cathode materials with high capacity and long-term cycle stability remains a challenge due to the polarization of Zn²⁺ , and reduction-oxidation materials, including various forms of MnO₂ , layered V₂O₅ vanadium -based compounds, and organic compounds, have been extensively studied as potential electrode materials. Although MnO₂ exhibits ideal cell performance, it currently fails to provide practicality and stability due to limited reversible capacity and rate capability, as well as low intrinsic electronic conductivity. Additionally, vanadium oxides such as V₂O₅ and VO₂ offer high capacity but have limitations due to insufficient rate capability. FIG. 1 is an image showing a conceptual diagram using a water-soluble electrolyte and a conceptual diagram of a zinc battery using a GPE electrolyte of one embodiment of the present invention. Figure 2 is a diagram showing the chemical reaction equations involved in the synthesis process of sV 2 O 5 ·0.56H 2 O. Figure 3 is a graph showing (A) X-ray diffraction (XRD) patterns of (a) bV₂O₅ and (b) sV₂O₅ · 0.56H₂O , and (B) TGA and DTA trace lines of sV₂O₅ · 0.56H₂O acquired at a rate of 10 °C/min under nitrogen conditions. Figure 4 shows (C) and (D) low-magnification and high-magnification FESEM images of bV₂O₅ , and (E) and (F) low-magnification and high -magnification images of sV₂O₅ · 0.56H₂O . Figure 5 shows (A, B) low-magnification and high-magnification HRTEM images of sV 2 O 5 ·0.56H 2 O, (C) SAED pattern, (DF) EDX map of V and O, and (G) energy-dispersive X-ray spectrum. Figure 6 shows (A) a photograph of Zn(OTf) 2 /EMIBF 4 /PVDF-HFP, a FESEM image of a GPE membrane, (B) pure PVDF-HFP, (C) Zn(OTf) 2 /PVDF-HFP, (D) EMIBF 4 /PVDF-HFP, and (E) an image of Zn(OTf) 2 /EMIBF 4 /PVDF-HFP. Figure 7 is an optical microscope image of (A) PVDF-HFP, (B) Zn(OTf) 2 /PVDF-HFP, (C) EMIBF 4 /PVDF-HFP, and (D) Zn(OTf) 2 /EMIBF 4 /PVDF-HFP. Figure 8 is a graph showing the XRD patterns of (a) pure PVDF-HFP, (b) Zn(OTf) 2 /PVDF-HFP, (c) EMIBF 4 /PVDF-HFP, and (d) Zn(OTf) 2 /EMIBF 4 /PVDF-HFP electrolytes. Figure