Preparation method of niobium titanium oxide / liquid metal composite negative electrode material and application thereof in low-temperature lithium ion battery

Abstract

The application relates to a preparation method of a niobium titanium oxide / liquid metal composite negative electrode material and application of the niobium titanium oxide / liquid metal composite negative electrode material in a low-temperature lithium ion battery, and belongs to the field of secondary batteries. The method is as follows: TiNb2O7 microspheres are synthesized, SnO2 is deposited on the surface of the TiNb2O7 by adopting an atomic layer deposition technology and taking SnCl4 and H2O as precursors, and TNO@Sn material is obtained through hydrogen reduction; TNO@Sn powder, Super P and PVDF are uniformly mixed in a solvent to prepare a slurry, the slurry is coated on a copper foil current collector, and an electrode sheet is obtained through rolling; Ga-In-Sn ternary eutectic liquid metal is prepared, the liquid metal is uniformly sprayed on the surface of the electrode sheet in an Ar atmosphere glove box, the Ga-In-Sn liquid metal / TiNb2O7 composite negative electrode is prepared in a "cold welding" mode, the interface bonding force between the liquid metal and the active particles is enhanced through an alloying reaction, the composite process temperature is reduced, and the damage of high temperature to the material is avoided. Meanwhile, the flowability, self-healing and high conductivity of the liquid metal compensate for and enhance the ion / electron transmission deficiency of the TiNb2O7 composite electrode at low temperature, and high safety is ensured.

Description

Technical Field

[0001] This invention relates to the field of secondary battery technology, specifically to a method for preparing a niobium-titanium oxide / liquid metal composite anode material and its application in low-temperature lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries have been widely used in consumer electronics, electric vehicles, and other fields due to their high energy density and long cycle life. However, in low-temperature environments (such as below 0°C), the negative electrode materials of traditional lithium-ion batteries (such as graphite) suffer from problems such as reduced ion diffusion rate, decreased electronic conductivity, and deteriorated SEI film stability. This leads to a sharp decline in battery capacity and reduced charge and discharge efficiency, severely limiting their application in special scenarios such as cold regions and high-altitude operations.

[0003] TiNb₂O₇, as a novel niobium-based oxide anode material, possesses advantages such as high theoretical capacity (~387 mAh / g), moderate lithium-ion diffusion coefficient, and good structural stability. Its structural stability at low temperatures is superior to that of graphite materials. However, TiNb₂O₇ itself has relatively low electronic conductivity (~10⁻⁶ mAh / g). -6 In low-temperature environments, the ion transport kinetics are further limited, resulting in low-temperature electrochemical performance that still cannot meet practical requirements. To improve its conductivity, existing technologies typically employ methods such as carbon coating and metal nanoparticle doping. However, carbon materials have limited ion transport capabilities at low temperatures, and high-temperature doping processes can easily lead to defects in the TiNb2O7 crystal structure, affecting the material's stability.

[0004] Liquid metals (such as Ga-In-Sn alloys) exhibit excellent electronic conductivity (≥10 Ω·cm at room temperature). 4 With its high flux density (S / cm), good fluidity, and self-healing ability, as well as its low melting point (Ga-In-Sn ternary eutectic alloys can reach as low as approximately -30°C), liquid metal remains liquid even at low temperatures, making it a promising material for improving the conductivity of low-temperature electrodes. However, the interfacial bonding between liquid metal and traditional electrode active particles is weak, leading to easy detachment. Furthermore, high-temperature composite processes can damage the crystal structure of oxide materials such as TiNb2O7, limiting their application in composite anode materials. Therefore, developing a low-temperature compatible, well-bonded niobium-titanium oxide / liquid metal composite anode fabrication technology is of great significance for improving the low-temperature performance of lithium-ion batteries. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of poor low-temperature conductivity and weak interfacial bonding between liquid metal and active particles in existing TiNb2O7 anode materials. It provides a method for preparing a highly conductive niobium-titanium oxide / liquid metal composite anode material and its application in low-temperature lithium-ion batteries. The invention achieves a strong bond between liquid metal and TNO@Sn active particles through a "cold welding" process. Simultaneously, it utilizes the high conductivity and fluidity of the liquid metal to improve the ion / electron transport efficiency of the composite anode at low temperatures, thereby obtaining a high-performance low-temperature lithium-ion battery.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing a niobium-titanium oxide / liquid metal composite anode material, the method comprising:

[0008] Step 1: Highly crystalline TiNb2O7 microspheres are synthesized from titanium and niobium sources using a hydrothermal method or a sol-gel method. The resulting TiNb2O7 microspheres have a particle size of 1~5μm and a porosity of 30%~50%, providing ample space for subsequent Sn nanodot deposition and liquid metal wetting.

[0009] Step 2: Using atomic layer deposition (ALD) technology, SnO2 film is deposited on the surface of TiNb2O7 microspheres obtained in Step 1, with SnCl4 and H2O as precursors. After reduction with hydrogen, SnO2 is reduced to Sn nanodots, resulting in TNO@Sn material with uniform and controllable size Sn nanodots. Sn nanodots not only improve the conductivity of the material, but also undergo alloying reactions with subsequent liquid metals, enhancing the interfacial bonding force.

[0010] Step 3: Mix the TNO@Sn powder obtained in Step 2, the conductive agent Super P, and the binder PVDF uniformly in N-methylpyrrolidone solvent to prepare a slurry;

[0011] Step 4: The slurry obtained in Step 3 is uniformly coated onto the copper foil current collector, and then rolled to obtain a dense electrode sheet;

[0012] Step 5: Prepare Ga-In-Sn ternary eutectic liquid metal. By adjusting the types and contents of elements, control the melting point of the alloy to -32℃ to -10℃, for example -30.1℃, -29.7℃, -20℃, and -11.6℃, so that it remains liquid at low temperatures. In an Ar atmosphere glove box, use precision spraying technology to uniformly apply the liquid metal to the surface of the dried electrode sheet obtained in Step 4. Through "cold welding", achieve alloying and bonding of liquid metal with TNO@Sn active particles (Sn nanodots) to form Sn-Ga-In alloy phase, so that liquid metal and TNO@Sn active layer are firmly bonded to obtain niobium titanium oxide / liquid metal composite anode material.

[0013] Further, in step one, the hydrothermal method involves mixing a titanium source (tetrabutyl titanate) and a niobium source (niobium pentachloride) in a mass ratio of 1.5 to 1.7:1 with ethanol to fully dissolve the titanium and niobium sources in the ethanol; reacting at 160 to 220°C for 12 to 36 hours, followed by washing and drying; the sol-gel method involves dissolving a titanium source (tetrabutyl titanate) and a niobium source (niobium pentachloride) in a mass ratio of 1.5 to 1.7:1 in ethanol, adding a chelating agent (citric acid, acetic acid, acetylacetone, etc.) in a molar ratio two to three times that of tetrabutyl titanate, aging at 25 to 60°C for 8 to 24 hours, and subsequently calcining at 800 to 900°C for 2 to 6 hours to form a porous structure. The preferred mass ratio of titanium source to niobium source is 1.59:1.

[0014] Further, in step two, the molar ratio of TiNb2O7 to SnCl4 and H2O is 96~98:1:1~3, preferably 97:1:2; the deposition temperature of the atomic layer deposition is 100~200℃, and the number of deposition cycles is 50~200; the temperature of the hydrogen reduction is 300~450℃, and the reduction time is 2~5h; the particle size of the obtained Sn nanodots is 5~20nm, and the loading is 5%~15% of the total mass of the TNO@Sn material.

[0015] Furthermore, in step three, the mass percentages of TNO@Sn powder, Super P, and PVDF are 80%~95%: 0%~10%: 5%~10%, and the solid content of the slurry is 30~50wt%.

[0016] Furthermore, in step four, the coating thickness of the slurry is 50~150μm, and the density of the rolled electrode sheet is 1.5~2.0g / cm³. 3 The rolling process can improve the contact density between active particles.

[0017] Further, in step five, the mass percentages of Ga, In, and Sn in the Ga-In-Sn ternary eutectic liquid metal are 50%~75%: 10%~25%: 13.5%~25%; the precision spraying pressure is 0.1~0.5MPa, the spraying distance is 5~15cm, and the amount of liquid metal applied is 0.5~2mg / cm³. 2 The process temperature for the “cold welding” is 25~80℃, and the holding time is 10~30min.

[0018] A niobium-titanium oxide / liquid metal composite anode material obtained by the above preparation method is disclosed. The composite anode material consists of a TNO@Sn active layer and a Ga-In-Sn liquid metal modification layer. The liquid metal and Sn nanodots form a Sn-Ga-In alloy phase with an interfacial bonding strength ≥1.5MPa, an electronic conductivity ≥100S / cm at room temperature, and an electronic conductivity ≥10S / cm at -40℃, which is significantly better than that of pure TiNb2O7 material.

[0019] The application of a niobium-titanium oxide / liquid metal composite anode material obtained by the above preparation method in a low-temperature lithium-ion battery, wherein the low-temperature lithium-ion battery includes a niobium-titanium oxide / liquid metal composite anode material, a cathode material, an electrolyte and a separator, wherein the low-temperature lithium-ion battery can be stably charged and discharged in a temperature range of -30℃ to 25℃, and the capacity retention rate after 500 cycles is ≥90%, exhibiting excellent low-temperature performance and cycle stability.

[0020] Furthermore, the positive electrode material is one of LiFePO4, NCM ternary material or LiCoO2, the electrolyte is a carbonate electrolyte containing LiPF6, and the separator is a polypropylene separator.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. Strong interface bonding and gentle process: The "cold welding" process is used for the first time. Through the alloying reaction of Sn nanodots and Ga-In-Sn liquid metal, a strong bond is achieved between liquid metal and TNO@Sn active particles (interface bonding strength ≥1.5MPa). This avoids the damage to the TiNb2O7 crystal structure caused by high-temperature composite processes. The process temperature is only 25~80℃, and the compatibility is good.

[0023] 2. Significantly improved conductivity at low temperatures: Liquid metal remains liquid at low temperatures, and its high conductivity (≥10S / cm at -30℃) and fluidity can build continuous electron transport channels, making up for the poor conductivity of TiNb2O7 itself. At the same time, the self-healing ability of liquid metal can repair microcracks in the electrode during cycling, ensuring the continuity of ion / electron transport.

[0024] 3. Excellent electrochemical performance: The composite anode material combines the high capacity of TiNb2O7 and the high conductivity of liquid metal. When applied to lithium-ion batteries, it can still maintain high capacity and long cycle life (≥90% retention rate after 500 cycles) at a low temperature of -30℃, solving the key problem of low-temperature performance degradation of traditional lithium-ion batteries.

[0025] 4. High safety: Ga-In-Sn liquid metal has stable chemical properties, is not flammable or explosive, and has good compatibility with electrolyte, which can better improve the safety performance of the battery. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the TiNb2O7 microspheres synthesized by hydrothermal method in Example 1;

[0027] Figure 2 Ga in Example 1 50 In 25 Sn 25 Comparison of the performance of TiNb2O7 electrode and TiNb2O7 electrode at -30℃;

[0028] Figure 3 Ga in Example 1 50 In 25 Sn 25 @Charge-discharge curves of TiNb2O7 electrode at -30℃ and 0.5C;

[0029] Figure 4 This is a curve showing the specific surface area of ​​the TiNb2O7 microspheres synthesized by the sol-gel method in Example 2.

[0030] Figure 5 Ga in Example 3 65 In 20 Sn 15 Charge-discharge curves of the TiNb2O7 electrode at -30℃ and 0.5C. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] This invention first synthesizes highly crystalline TiNb2O7 microspheres using a hydrothermal or sol-gel method. Then, using atomic layer deposition (ALD) with SnCl4 and H2O as precursors, SnO2 is deposited on the TiNb2O7 surface. Subsequent hydrogen reduction yields TNO@Sn material with uniformly sized, controllable Sn nanodots. Next, TNO@Sn powder, Super P, and PVDF are uniformly mixed in N-methylpyrrolidone solvent to form a slurry. The slurry is uniformly coated onto a copper foil current collector and rolled to obtain a dense electrode sheet. Ga-In-Sn ternary eutectic liquid metal is prepared and uniformly applied to the dry electrode sheet surface using precision spraying technology in an Ar atmosphere glove box. This invention is the first to employ a "cold welding" method to prepare a Ga-In-Sn liquid metal / TiNb2O7 composite anode. The alloying reaction enhances the interfacial bonding between the liquid metal and the active particles, lowers the composite process temperature, and avoids high-temperature damage to the material. Simultaneously, the fluidity, self-healing properties, and high conductivity of liquid metal are utilized to compensate for and enhance the shortcomings of TiNb2O7 composite electrodes in ion / electron transport at low temperatures, while ensuring high safety.

[0033] Example 1

[0034] 1. Synthesis of TiNb2O7 microspheres: Tetrabutyl titanate (0.02 mol) and niobium pentachloride (0.04 mol) were dissolved in 50 mL of ethanol by hydrothermal method. After stirring evenly, the solution was transferred to a 100 mL hydrothermal reactor and reacted at 180 °C for 24 h. After the reaction was completed, the product was centrifuged, washed with ethanol 5 times, and dried at 80 °C for 12 h to obtain TiNb2O7 microspheres.

[0035] 2. Preparation of TNO@Sn material: Atomic layer deposition was used with SnCl4 and H2O as precursors. The deposition temperature was 150℃ and the deposition cycle was 100 times. Then, the sample was placed in a tube furnace and hydrogen gas was introduced (flow rate 50 ml / min). The reduction was carried out at 350℃ for 3 h to obtain TNO@Sn material with Sn nanodot loading of 10%. The particle size of the obtained Sn nanodots was 5~20 nm.

[0036] 3. Electrode preparation: TNO@Sn powder, Super P, and PVDF were weighed at a mass ratio of 8:1:1, and NMP solvent was added. The mixture was stirred for 2 hours to prepare a slurry with a solid content of 40wt%. The slurry was coated onto copper foil to a thickness of 100μm, and then rolled at 10MPa to obtain an areal loading of approximately 1.8mg / cm². 2 Electrode plates.

[0037] 4. Composite Anode Preparation: Ga-In liquid metal was prepared with a mass fraction to pre-deposited Sn ratio of Ga:In:Sn = 50:25:25. In an Ar atmosphere glove box, the liquid metal was sprayed onto the electrode surface using precision spraying technology (pressure 0.3 MPa, distance 10 cm), with an application rate of 1 mg / cm². 2 Then, the material is kept at 60℃ for 20 minutes to complete the "cold welding" and obtain the composite negative electrode material.

[0038] 5. Low-temperature lithium-ion battery assembly and testing: Using lithium sheets as the positive electrode, 1 mol / L LiPF6 / EC-DMC-DEC (volume ratio 1:1:1) as the electrolyte, and PP separator, CR2032 coin cells were assembled and tested at -30℃ with a 0.5C charge-discharge rate.

[0039] Example 2

[0040] 1. Synthesis of porous TiNb2O7 microspheres: The sol-gel method was used to dissolve tetrabutyl titanate (0.02 mol) and niobium pentachloride (0.04 mol) in 30 mL of ethanol, add citric acid (0.05 mol), and age at 40 °C for 12 h; then calcine at 850 °C for 4 h to obtain porous TiNb2O7 microspheres with a particle size of 3~4 μm and a porosity of 35%.

[0041] 2. Preparation of TNO@Sn material: Atomic layer deposition temperature 180℃, deposition cycle 150 times; hydrogen reduction temperature 400℃, reduction time 4h, to obtain TNO@Sn material with Sn nanoparticle size of 15~20nm and loading of 12%.

[0042] 3. Electrode preparation: TNO@Sn powder, Super P, and PVDF were mixed in a mass ratio of 8:1:1; the slurry solid content was 40wt%; the coating thickness was 100μm; and the density of the electrode sheet after rolling was 1.8g / cm³. 3 .

[0043] 4. Composite anode preparation: Ga-In-Sn liquid metal mass ratio 60:25:15, spraying pressure 0.3MPa, distance 10cm, application rate 1mg / cm. 2 Keep warm at 60℃ for 20 minutes.

[0044] 5. Low-temperature lithium-ion battery assembly and testing: Using LiFePO4 as the positive electrode, 1mol / L LiPF6 / EC-DMC-DEC (volume ratio 1:1:1) as the electrolyte, and PP separator, CR2032 coin cells were assembled and tested at -30℃ with a 0.5C charge-discharge rate.

[0045] Example 3

[0046] 1. Synthesis of porous TiNb2O7 microspheres: Tetrabutyl titanate (0.02 mol) and niobium pentachloride (0.04 mol) were dissolved in 50 mL of ethanol, stirred evenly, and then transferred to a 100 mL hydrothermal reactor. The reaction was carried out at 180 °C for 24 h. After the reaction was completed, the product was centrifuged, washed with ethanol 5 times, and dried at 80 °C for 12 h to obtain TiNb2O7 microspheres.

[0047] 2. Preparation of TNO@Sn material: Atomic layer deposition temperature 200℃, deposition cycle 200 times; hydrogen reduction temperature 450℃, reduction time 5h, to obtain TNO@Sn material with Sn nanoparticle size of 18~20nm and loading of 15%.

[0048] 3. Electrode preparation: TNO@Sn powder, Super P, and PVDF were mixed in a mass ratio of 85:5:10; the slurry solid content was 30wt%; the coating thickness was 150μm; and the electrode density after rolling was 2.0g / cm³. 3 .

[0049] 4. Composite anode preparation: Ga-In-Sn liquid metal mass ratio 65:20:15, spraying pressure 0.5MPa, distance 5cm, application rate 2mg / cm. 2 Keep warm at 80℃ for 10 minutes.

[0050] 5. Battery Testing: CR2032 coin cells were assembled using LiCoO2 as the positive electrode, 1 mol / L LiPF6 / EC-DEC-EMC (volume ratio 2:1:1) as the electrolyte, and a polypropylene / polyethylene composite separator. The cells were then subjected to a 0.2C charge-discharge test at -30℃.

[0051] Comparative Example 1

[0052] The TNO electrode sheet was prepared using step 1 of Example 1 without liquid metal modification, and the battery was directly assembled.

[0053] Comparative Example 2

[0054] The TNO@Sn electrode sheet was prepared using steps 1-3 of Example 1, and the liquid metal was hot-pressed and bonded to the electrode sheet at 200°C for 30 min.

[0055] Figure 1 The TiNb2O7 microspheres synthesized by hydrothermal method in Example 1 have an average particle size of approximately 4 μm.

[0056] Figure 2 Ga in Example 1 50 In 25 Sn 25A comparison of the -30℃ performance of the TiNb2O7 electrode and the TiNb2O7 electrode in Comparative Example 1 shows that at -30℃ and 0.5C, Ga... 50 In 25 Sn 25 The discharge specific capacity of @TiNb2O7 is approximately 99 mAh / g, significantly higher than the 75 mAh / g of TiNb2O7. After 120 cycles, the capacity retention is 97.3%.

[0057] Figure 3 Ga in Example 1 50 In 25 Sn 25 The charge-discharge curves of the TiNb2O7 electrode and the TiNb2O7 electrode of Comparative Example 1 at -30℃ and 0.5C show that the liquid metal composite electrode has a higher capacity and a wider charge-discharge platform than the TiNb2O7 electrode.

[0058] Figure 4 The image shows the specific surface area test curve for the TiNb2O7 microspheres synthesized by the sol-gel method in Example 2. The calculated specific surface area of ​​the microspheres is 4.73 m². 2 / g.

[0059] Figure 5 Ga in Example 3 65 In 20 Sn 15 The charge-discharge curve of the TiNb2O7 electrode at -30℃ and 0.5C shows that the discharge specific capacity of the battery is 120mAh / g. It can be seen that as the proportion of Ga in the liquid ternary alloy increases, the melting point of the metal decreases and the alloy has better fluidity, thus enabling the battery to have a higher capacity.

[0060] The specific embodiments described above are used to illustrate the technical solutions of the present invention and are not intended to limit the invention. Those skilled in the art can make appropriate adjustments to the raw material ratios, process parameters, etc., within the scope of protection of the present invention, all of which fall within the scope of protection of the present invention. For example, adjusting the synthesis method of TiNb2O7, the loading amount of Sn nanodots, the composition ratio of liquid metal, etc., as long as the "cold welding" process of the present invention is used to achieve the composite of liquid metal and TNO@Sn, all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a niobium-titanium oxide / liquid metal composite anode material, characterized in that: The method is as follows: Step 1: Use titanium and niobium sources to synthesize highly crystalline TiNb2O7 microspheres via hydrothermal or sol-gel methods; Step 2: Using atomic layer deposition technology, SnO2 film is deposited on the surface of TiNb2O7 microspheres obtained in Step 1 with SnCl4 and H2O as precursors. After reduction with hydrogen, TNO@Sn material with Sn nanodots attached is obtained. Step 3: Mix the TNO@Sn powder obtained in Step 2, the conductive agent Super P, and the binder PVDF uniformly in N-methylpyrrolidone solvent to prepare a slurry; Step 4: The slurry obtained in Step 3 is uniformly coated onto the copper foil current collector, and then rolled to obtain a dense electrode sheet; Step 5: Prepare Ga-In-Sn ternary eutectic liquid metal. By adjusting the types and contents of elements, the melting point of the alloy is controlled at -32℃ to -10℃, so that it remains liquid at low temperatures. In an Ar atmosphere glove box, the liquid metal is uniformly applied to the surface of the dried electrode sheet obtained in Step 4 using precision spraying technology. The liquid metal is then alloyed with the TNO@Sn active particles (Sn nanodots) through "cold welding" to form a Sn-Ga-In alloy phase. This allows the liquid metal to be firmly bonded to the TNO@Sn active layer, resulting in a niobium-titanium oxide / liquid metal composite anode material.

2. The preparation method according to claim 1, characterized in that: In step one, the hydrothermal method involves mixing a titanium source (tetrabutyl titanate) and a niobium source (niobium pentachloride) in a mass ratio of 1.5 to 1.7:1 with ethanol to fully dissolve the titanium and niobium sources in the ethanol; reacting at 160 to 220°C for 12 to 36 hours, followed by washing and drying; the sol-gel method involves dissolving a titanium source (tetrabutyl titanate) and a niobium source (niobium pentachloride) in a mass ratio of 1.5 to 1.7:1 in ethanol, adding a chelating agent (citric acid, acetic acid, acetylacetone, etc.) in a molar ratio two to three times that of tetrabutyl titanate, aging at 25 to 60°C for 8 to 24 hours, and subsequently calcining at 800 to 900°C for 2 to 6 hours to form a porous structure.

3. The preparation method according to claim 1, characterized in that: In step two, the molar ratio of TiNb2O7 to SnCl4 and H2O is 96~98:1:1~3; the deposition temperature of the atomic layer deposition is 100~200℃, and the number of deposition cycles is 50~200; the temperature of the hydrogen reduction is 300~450℃, and the reduction time is 2~5h.

4. The preparation method according to claim 1, characterized in that: In step three, the mass percentages of TNO@Sn powder, Super P, and PVDF are 80%~95%: 0%~10%: 5%~10%, and the solid content of the slurry is 30~50wt%.

5. The preparation method according to claim 1, characterized in that: In step four, the coating thickness of the slurry is 50~150μm, and the density of the rolled electrode sheet is 1.5~2.0g / cm³. 3 .

6. The preparation method according to claim 1, characterized in that: In step five, the mass percentages of Ga, In, and Sn in the Ga-In-Sn ternary eutectic liquid metal are 50%~75%: 10%~25%: 13.5%~25%; the precision spraying pressure is 0.1~0.5MPa, the spraying distance is 5~15cm, and the amount of liquid metal applied is 0.5~2mg / cm³. 2 The process temperature for the "cold welding" is 25~80℃, and the holding time is 10~30min.

7. A niobium-titanium oxide / liquid metal composite anode material obtained by any of the preparation methods described in claims 1 to 6.

8. The application of a niobium-titanium oxide / liquid metal composite anode material obtained by any one of the preparation methods described in claims 1 to 6 in a low-temperature lithium-ion battery, characterized in that: The low-temperature lithium-ion battery includes a niobium-titanium oxide / liquid metal composite negative electrode material, a positive electrode material, an electrolyte, and a separator. The low-temperature lithium-ion battery can be stably charged and discharged within a temperature range of -30°C to 25°C.

9. The application according to claim 8, characterized in that: The positive electrode material is one of LiFePO4, NCM ternary material or LiCoO2, the electrolyte is a carbonate electrolyte containing LiPF6, and the separator is a polypropylene separator.

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