A rechargeable sodium-ion battery and a solid-state electrolyte material thereof

Abstract

The application relates to the technical field of solid-state batteries, in particular to a rechargeable sodium ion battery and a solid-state electrolyte material thereof. a M b S c , wherein 0 < a <= 6; M is one of B, Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, Sb, Bi, Se, Te; 0 < b <= 4; 0 < c <= 10. The compound is used as a solid-state electrolyte of a sodium ion battery, realizes high ionic conductivity of the sodium ion battery, focuses on solving the safety application problem of the sodium ion battery, breaks through the limitation of poor thermal stability of a traditional liquid-state electrolyte of the sodium ion battery, and simultaneously has low grain boundary resistance and good mechanical properties. Application of the solid-state electrolyte significantly improves the use safety of the battery and improves the energy density of the sodium ion battery.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery technology, and in particular to a rechargeable sodium-ion battery and its solid electrolyte material. Background Technology

[0002] Developing renewable and clean energy is one of the global strategies to avoid energy crises and environmental degradation. Rechargeable batteries are the core of renewable energy technology and have wide applications, such as electric vehicles, large-scale energy storage systems, and some emerging applications requiring high energy density (such as electric aircraft and trucks). Lithium-ion batteries have dominated the battery market due to their high energy density, long lifespan, high power handling capacity, light weight, and environmental friendliness. However, the global demand for high-energy-density rechargeable batteries has increased significantly, and over-reliance on lithium-ion batteries is unrealistic due to their high price and resource scarcity. Therefore, it is necessary to shift towards exploring new battery systems to meet the huge future demand. Sodium-ion batteries (SIBs) are an exciting alternative to lithium-ion energy storage. In addition to the abundance and low cost of sodium resources, they also have a "rocking chair" mechanism similar to lithium-ion batteries. Sodium-ion batteries are widely recognized as ideal rechargeable batteries for future low-speed electric vehicles and large-scale energy storage systems. However, existing sodium-ion battery electrolytes suffer from many problems, including poor thermal stability and flammability, poor long-cycle stability and high-rate characteristics, and high manufacturing costs. Finding a sodium-ion battery electrolyte with high safety and excellent electrochemical performance is one of the keys to the practical application of sodium-ion energy storage batteries.

[0003] Traditional liquid electrolytes, such as ether-based electrolytes, ester-based electrolytes, carbonate-based electrolytes, and ionic liquid electrolytes, have been successfully applied in sodium-ion batteries with high ionic conductivity. However, these liquid electrolytes are prone to serious safety problems due to their volatility, thermal instability, flammability, and mechanical structural instability, which hinders their application in large-scale energy storage.

[0004] In summary, existing sodium-ion battery electrolytes have many shortcomings. Therefore, solid-state electrolytes, due to their non-flammability, good thermal stability, good mechanical properties, and wider ESW (Electrostatic Discharge) values, have been proposed to address these issues, playing a significant role in the development of sodium-ion batteries. The solid-state electrolyte of this invention, when applied to sodium-ion batteries, can simultaneously achieve significant energy density and excellent safety performance. Furthermore, sodium-ion batteries using these solid-state electrolytes can achieve a wider operating temperature range. The solid-state electrolyte of this invention can further broaden the applicability of sodium-ion batteries, overcome technical barriers, and thus replace existing lithium-ion systems. The main objective of this invention is to use this solid-state electrolyte in sodium-ion batteries, thereby enabling the battery to achieve good ionic conductivity, a wider ESW value, good thermal stability, and good mechanical properties. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the background technology by proposing a rechargeable sodium-ion battery and its solid electrolyte material, which has good ionic conductivity, a wider ESW value range, good thermal stability, and good mechanical properties.

[0006] The present invention provides a rechargeable sodium-ion battery and its solid electrolyte material, comprising an electrolyte with the general chemical formula Na. a M b S c Sodium-ion batteries have the following structures: sodium-ion full cell (negative electrode | solid electrolyte | positive electrode), sodium-sodium symmetric cell (Na electrode | solid electrolyte | Na electrode), and sodium half cell (Na electrode | solid electrolyte).

[0007] Where M is one or more of B, Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, Sb, Bi, Se, and Te;

[0008] Preferably, M is one or more of Al, Si, Ge, and P;

[0009] More preferably, M is Si or P.

[0010] a is between 0 and 6 and includes 6; preferably, a = 3.

[0011] b is between 0 and 4 and includes 4; preferably, b = 1.

[0012] c is between 0 and 10 and includes 10; preferably, c = 4.

[0013] This invention provides a rechargeable sodium-ion battery, the rechargeable sodium-ion battery comprising: the positive electrode, sodium-ion solid electrolyte, and negative electrode described in the first aspect above;

[0014] The cathode materials for sodium-ion batteries include hard carbon (HC), Prussian blue (PB), 3,4,9,10-perylenetetracarboxylic acid dianhydride (PTCDA), and O3-Na (Ni 0.3 Fe 0.4 Mn 0.3 O2(NFM), O3-NaCu 1 / 9 Ni 2 / 9 Fe 1 / 3 Mn 1 / 3 O2(CNFM), Na3V2(PO4)3(NVP), Na3V2(PO4)2O2F(NVPOF), Na3V2(PO4)2F3, Na 1.5 VPO 4.8 F 0.7, NaTi2(PO4)3(NTP), S@MPCF, Na 0.7 (Fe 0.5 Mn 0.5 O2, Na 0.44 One or more of MnO2, MCMB, Sn–C, and S-MWCNTs;

[0015] Preferably, the cathode material of the sodium-ion battery includes Na(Ni) 0.3 Fe 0.4 Mn 0.3 O2(NFM), O3-NaCu 1 / 9 Ni 2 / 9Fe 1 / 3 Mn 1 / 3 One or more of the following: O2 (CNFM), Na3V2(PO4)3 (NVP), Na3V2(PO4)2O2F (NVPOF), and NaTi2(PO4)3 (NTP);

[0016] More preferably, the cathode material of sodium-ion batteries includes Na(Ni) 0.3 Fe 0.4 Mn 0.3 One or more of O2 (NFM), Na3V2(PO4)3 (NVP), and Na3V2(PO4)2O2F (NVPOF).

[0017] Sodium metal anodes include one or more of the following: sodium foil, sodium powder, sodium mesh, and sodium alloy;

[0018] Carbon anode materials include one or more of the following: mesophase carbon microsphere graphite, natural graphite, expanded graphite, artificial graphite, glassy carbon, carbon fiber, hard carbon, soft carbon, activated carbon, porous carbon, carbon cloth, carbon paper, three-dimensional graphite, carbon black, carbon nanotubes, graphene, and modified materials of the above carbon materials.

[0019] Preferably, the sodium metal negative electrode is sodium foil and hard carbon.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] The solid electrolyte provided by this invention not only achieves high ionic conductivity in sodium-ion batteries but also addresses the key safety issues associated with their application, overcoming the limitation of poor thermal stability inherent in traditional liquid electrolytes for sodium-ion batteries. Furthermore, compared to other solid electrolytes, the ionic conductivity of the sulfide solid electrolyte (taking Na3PS4 as an example) at room temperature is similar to its bulk conductivity (both approximately 2 × 10⁻⁶). -4The low grain boundary resistance (S / cm) of this solid-state electrolyte demonstrates its low grain boundary resistance. Furthermore, existing studies have shown that the sulfide solid-state electrolyte exhibits low Mayer hardness (approximately 0.66 GPa) and moderate Young's modulus (approximately 21 GPa), indicating good mechanical properties. This solid-state electrolyte also combines low grain boundary resistance with good mechanical properties. The application of this solid-state electrolyte significantly improves battery safety and enhances the energy density of sodium-ion batteries. Attached Figure Description

[0022] Figure 1 It is Na4Si4S 10 Crystal structure diagram;

[0023] Figure 2 It is Na4Si4S 10 ionic conductivity diagram;

[0024] Figure 3 This is a graph showing the ionic conductivity of NASICON electrolytes. Detailed Implementation

[0025] Example 1

[0026] like Figure 1 As shown, Na4Si4S 10 Crystal structure diagram

[0027] Performance tests are as follows:

[0028] A Na / Na symmetric solar cell was prepared, and the M prepared in this invention was subjected to cycle testing. The specific assembly steps involved combining Na₄Si₄S₂... 10 Solid electrolyte, stainless steel (SS) sheet composition SS / Na4Si4S 10 The ionic conductivity of the battery was measured using electrochemical impedance spectroscopy (EIS) with a blocked / SS electrode. At room temperature, an AC voltage was applied across the electrode, and EIS data were collected with a 10 mV perturbation within a frequency range of 10⁶–10⁻² Hz. The impedance diagram was analyzed and fitted using Zview software. The results are shown below. Figure 1 As shown in the figure, the calculated ionic conductivity is 5.5 × 10⁻³ S / cm.

[0029] Comparative Example 1

[0030] The NASICON electrolyte was prepared using the same method as described in this application, and battery testing was performed. Specifically, the assembly steps involved combining the NASICON electrolyte and stainless steel (SS) sheets to form an SS / NASICON / SS blocked electrode. Electrochemical impedance spectroscopy (EIS) was used to test the ionic conductivity of the battery: at room temperature, an AC voltage was applied across the electrode, and EIS data were collected with a 10 mV perturbation within a frequency range of 10⁶–10⁻² Hz. The impedance diagram was analyzed and fitted using Zview software, and the results are shown below. Figure 2 As shown in the figure, the calculated ionic conductivity is 4.3 × 10⁻⁴ S / cm.

[0031] The results of Example 1 and Comparative Example 1 show that the solid electrolyte prepared by the present invention achieves high ionic conductivity in sodium-ion batteries, and also solves the safety application problem of sodium-ion batteries, overcoming the limitation of poor thermal stability of liquid electrolytes in traditional sodium-ion batteries.

[0032] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A rechargeable sodium-ion battery, characterized in that, It includes a positive electrode, a sodium-ion solid electrolyte, and a negative electrode; the chemical formula of the sodium-ion solid electrolyte is Na₄Si₄S. 10 ; Sodium-ion batteries can be structured as sodium-ion full cells, sodium-sodium symmetric cells, or sodium half cells.

2. A rechargeable sodium-ion battery according to claim 1, characterized in that, Sodium-ion battery cathode materials include Prussian blue, 3,4,9,10-perylenetetracarboxylic acid dianhydride, and O3-Na(Ni) 0.3 Fe 0.4 Mn 0.3 O2, O3−NaCu 1 / 9 Ni 2 / 9 Fe 1 / 3 Mn 1 / 3O2, Na3V2(PO4)3, Na3V2(PO4)2O2F, Na3V2(PO4)2F3, Na 1.5 VPO 4.8 F 0.7 NaTi2(PO4)3, S@MPCF, Na 0.7 (Fe 0.5 Mn 0.5 O2, Na 0.44 One or more of MnO2.

3. A rechargeable sodium-ion battery according to claim 1, characterized in that, The negative electrode includes one or more of the following: sodium foil, sodium powder, sodium mesh, sodium alloy, and carbon materials.

4. A rechargeable sodium-ion battery according to claim 3, characterized in that, Carbon materials include one or more of the following: natural graphite, expanded graphite, artificial graphite, carbon fiber, hard carbon, soft carbon, activated carbon, carbon black, carbon nanotubes, graphene, and modified materials of the above carbon materials.

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