Zero-strain carbon negative electrode material and preparation method and application thereof
By introducing Al or Si precursors into the graphite cathode from electrolytic aluminum waste to form chemical bonds, the interlayer bonding force is enhanced, solving the problem of battery capacity decay caused by volume changes in traditional lithium-ion battery anode materials, and achieving zero-strain characteristics and long-life batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-04-03
AI Technical Summary
Traditional lithium-ion battery anode materials undergo large volume changes during lithium-ion insertion/extraction, leading to electrode pulverization and repeated SEI film formation, resulting in rapid capacity decay and short cycle life.
The method involves mixing waste aluminum cathode graphite with Al or Si precursors, and then sintering to form Al-C or Si-C chemical bonds, which are anchored between graphite layers to enhance interlayer bonding and achieve zero-strain characteristics.
It improves battery cycle stability and lifespan, reduces resource waste, lowers total life cycle cost, conforms to the concept of circular economy, and provides more efficient resource utilization and battery performance.
Smart Images
Figure CN121790334A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of regenerative application technology, specifically relating to a zero-strain carbon anode material, its preparation method, and its application. Background Technology
[0002] With the accelerated progress towards global carbon neutrality goals, electric vehicles and energy storage systems are irreversibly reshaping the energy industry landscape, becoming the core engine driving the explosive growth of the lithium-ion battery market. The global lithium-ion battery market is enormous, with power batteries dominating with over 60% market share, followed closely by energy storage batteries at 15%. Together, they constitute the "dual engines" driving the demand for lithium-ion batteries.
[0003] In the microscopic world of lithium-ion batteries, the volume stability of electrode materials is crucial, directly determining the battery's cycle life and safety performance. Zero-strain materials refer to electrode materials (specifically negative electrode materials) whose volume change is less than 2% during lithium-ion insertion / extraction. These materials, with their unique physical properties, are becoming key to solving problems such as electrode fragmentation and repeated SEI film formation.
[0004] When lithium ions move between the crystal lattices of electrode materials during charging and discharging, the volume of the material inevitably expands or contracts. For traditional materials, this volume change induces enormous stress within the electrode, causing the electrode material to pulverize and detach from the current collector, resulting in a rapid decrease in battery capacity. Taking commercially available graphite as an example, during lithium-ion insertion / extraction, the layered structure of natural graphite exhibits significant volume differences due to the uneven distribution of lithium ions, leading to a volume expansion rate as high as 10%-20%. This drastic volume change makes natural graphite electrodes extremely prone to pulverization during cycling, deteriorating the electrical contact between particles and causing rapid capacity decay. Simultaneously, the newly exposed electrode surface continuously reacts with the electrolyte to form a new SEI film (solid electrolyte interface film). This process not only consumes a large number of lithium ions but also thickens the SEI film, increasing the battery's internal resistance and ultimately causing a sharp deterioration in battery performance.
[0005] The hazardous solid waste generated during electrolytic aluminum production mainly consists of waste carbonaceous anode and cathode materials. These contain harmful substances such as fluorides, but due to the high value of their residual carbon, they can be treated harmlessly and recycled. Therefore, it is essential to convert waste graphite from electrolytic aluminum production into high-value-added lithium-ion battery anode materials.
[0006] In summary, the intrinsic zero-strain graphite lithium-ion battery anode material derived from waste aluminum electrolytic cathodes proposed in this invention has significant advantages over existing products in terms of performance, cost, and resource recycling. It effectively solves the problems existing in traditional electrode materials and brings new opportunities and hope for the development of the lithium-ion battery industry and the global energy transition. Summary of the Invention
[0007] To address or partially address the problems existing in related technologies, this invention proposes a zero-strain carbon anode material, its preparation method, and its application.
[0008] This invention provides a method for preparing a zero-strain carbon anode material, comprising the following steps: (1) Mixing waste aluminum cathode graphite with substance A to obtain mixture A, wherein substance A is an Al precursor and / or a Si precursor; (2) Sinter the mixture A to obtain the zero-strain carbon anode material prepared from the waste cathode of electrolytic aluminum.
[0009] Preferably, the Al precursor is at least one selected from AlCl3, aluminum oxide, aluminum hydroxide, aluminum-based metal-organic frameworks, aluminum isopropoxide, aluminum sec-butoxide, aluminum ethoxide, trimethylaluminum, and triethylaluminum.
[0010] Preferably, the Si precursor is silicon tetrachloride, sodium silicate, tetraethyl orthosilicate, dimethyldichlorosilane, aminosilane, Si3N4, Si, SiO2, SiO, or SiO2. x At least one of them.
[0011] Preferably, the particle size of the waste aluminum cathode graphite is 10nm-500um.
[0012] Preferably, the sintering temperature is 700-1600℃ and the time is 1-12h.
[0013] Preferably, the mass ratio of the waste aluminum cathode graphite to substance A is (20-100):(0.1-2).
[0014] The present invention also claims protection for the zero-strain carbon anode material prepared by the method for preparing the zero-strain carbon anode.
[0015] Preferably, the zero-strain carbon anode material comprises carbon material and Al and / or Si single atoms between the carbon layers. In this invention, the Al and Si atoms form stable, covalent Al-C and Si-C chemical bonds with the carbon substrate through a "bridge" structure, exhibiting strong interactions. After sintering, Al and / or Si single atoms can form between the carbon layers, contributing to the intrinsic zero-strain characteristics and excellent cycle stability of the battery. Compared to doping or loading Al and / or Si onto graphene, this invention anchors the graphite sheets through chemical bonds, significantly enhancing the interlayer bonding force and effectively increasing its resistance to deformation, thus achieving zero-strain characteristics. Ordinary doping and loading only modify individual carbon sheets, having a very limited impact on interlayer bonding force and making strain control difficult.
[0016] The present invention also claims protection for a negative electrode comprising a negative electrode current collector and a negative electrode active material layer, wherein the negative electrode active material layer is disposed on at least one surface of the negative electrode current collector, and the negative electrode active material layer comprises a zero-strain carbon negative electrode material.
[0017] Preferably, the negative electrode active material layer further includes a binder and a conductive agent.
[0018] The technical solution of the present invention has the following beneficial effects: (1) The present invention achieves intrinsic zero strain characteristics and excellent cyclic stability by converting Al and / or Si precursors into single atoms anchored in the interlayer of graphite, which plays a “pinning” role.
[0019] (2) The zero-strain carbon anode material prepared from waste cathodes of electrolytic aluminum provided by this invention effectively utilizes waste resources, reduces resource waste, lowers the demand for and mining of new graphite materials, and reduces carbon emissions during the mining and production of new graphite, as mining and processing graphite typically consumes a large amount of energy and generates greenhouse gases. This improves resource utilization efficiency, reduces the demand for raw resources and the environmental costs required for waste treatment, and aligns with the circular economy concept advocated in the dual-carbon plan.
[0020] (3) Considering the purchase cost, maintenance cost, and replacement cost of the battery, the zero-strain carbon anode material prepared based on waste cathodes from electrolytic aluminum has a lower total life cycle cost. Due to its superior performance, the probability of battery failure during use is low, resulting in lower maintenance costs. Moreover, the longer cycle life reduces the frequency of battery replacement and lowers replacement costs. In contrast, batteries prepared with traditional anode materials have higher total life cycle costs due to performance limitations.
[0021] (4) Compared to natural graphite electrodes, which are prone to problems such as electrode pulverization and repeated SEI film formation during cycling due to large volume changes, resulting in rapid capacity decay and short cycle life, zero-strain waste graphite effectively avoids electrode structure damage and repeated SEI film formation due to its zero-strain characteristics, greatly improving battery cycle life. It effectively solves the problems existing in traditional electrode materials, bringing new opportunities and hope for the development of the lithium-ion battery industry and global energy transition. Attached Figure Description
[0022] Figure 1 This is a spherical aberration TEM image of the zero-strain carbon anode material prepared in Example 1.
[0023] Figure 2 This is a graph showing the charge-discharge cycle performance of the lithium-ion battery prepared in Example 1.
[0024] Figure 3 This is the charge-discharge XRD pattern of the zero-strain carbon anode material prepared in Example 1.
[0025] Figure 4 This is the charge-discharge Raman diagram of the zero-strain carbon anode material prepared in Example 1. Detailed Implementation
[0026] Example 1 A method for preparing a zero-strain carbon anode material includes the following steps: (1) 20g of material with a specific surface area of 1m² 2 / g, waste cathode graphite of electrolytic aluminum with a particle size of 10nm-500um is mixed with 0.1g of substance A to obtain mixture A, which is a mixture of AlCl3 and SiCl4 with a mass ratio of AlCl3 to SiCl4 of 1:1.
[0027] (2) The mixture A was sintered at 1000℃ for 8 hours to obtain the zero-strain carbon anode material prepared from the waste cathode of electrolytic aluminum.
[0028] A method for preparing a lithium-ion battery, comprising: (1) The 160 mg zero-strain carbon anode material, 20 mg PVDF binder, and 20 mg superconducting carbon black powder conductive agent prepared above were evenly dispersed in 0.4 ml N-methylpyrrolidone (NMP) and coated onto a 12 μm copper foil current collector with a coating amount of 10 mg / cm. 2 Then, it is vacuum dried to produce a negative electrode sheet.
[0029] (2) Using superconducting carbon black as a conductive agent, PVDF as a binder, and NMP as a solvent, after stirring evenly, LiFePO4, the positive electrode active material, was added to obtain a mixture, which was then coated onto the surface of a 10μm Al foil with a coating amount of 21mg / cm. 2 The positive electrode is then formed. The solid components of the mixture include 90 wt.% LiFePO4, 5 wt.% PVDF binder, and 5 wt.% conductive carbon black.
[0030] (3) The negative electrode, positive electrode, electrolyte, and polyolefin microporous membrane are assembled into a soft-pack lithium-ion battery by winding, and the battery is sealed with commonly used tabs and aluminum-plastic film. The electrolyte is a 1M LiPF6 / (EC+DEC, 1:1) commercial electrolyte.
[0031] The spherical aberration TEM morphology of the negative electrode obtained in Example 1 is as follows: Figure 1 As shown, Al and Si can be observed anchored on graphite in single-atom form. The cycle performance of the lithium-ion battery is as follows... Figure 2 As shown, it can be observed that after 2000 cycles, its specific capacity hardly decreases, indirectly demonstrating its intrinsic zero-strain characteristics. Figure 3 The in-situ XRD pattern obtained during the charging and discharging process of the negative electrode in Example 1 shows that no phase transformation (solid solution mechanism) occurred during the entire charging and discharging process, and the lattice did not shrink / stretch, which directly proves its intrinsic zero strain characteristics. Figure 4 The in-situ Raman spectrum of the negative electrode obtained in Example 1 shows that its Raman spectrum hardly changed, further proving its intrinsic zero-strain characteristics.
[0032] Example 2 A method for preparing a zero-strain carbon anode material includes the following steps: (1) 20g of material with a specific surface area of 1m² 2 Mixture A is obtained by mixing layered waste cathode graphite with a particle size of 10nm-500um with 0.1g AlCl3.
[0033] (2) The mixture A was sintered at 700°C for 12 hours to obtain the zero-strain carbon anode material prepared from the waste cathode of electrolytic aluminum.
[0034] A method for preparing a lithium-ion battery, comprising: (1) The 240 mg zero-strain carbon anode material, 30 mg PVDF binder, and 30 mg superconducting carbon black powder conductive agent prepared above were evenly dispersed in 0.6 ml N-methylpyrrolidone (NMP) and coated onto a 12 μm copper foil current collector with a coating amount of 10 mg / cm. 2 Then, it is vacuum dried to produce a negative electrode sheet.
[0035] (2) Using superconducting carbon black as a conductive agent, PVDF as a binder, and NMP as a solvent, after stirring evenly, LiFePO4, the positive electrode active material, was added to obtain a mixture, which was then coated onto the surface of a 10μm Al foil with a coating amount of 21mg / cm. 2 The positive electrode is then fabricated. The solid component of the mixture contains 90 wt.% lithium cobalt oxide (LiNi). 0.8 Co 0.1 Mn 0.1 O2), 5 wt.% binder PVDF and 5 wt.% conductive carbon black.
[0036] (3) The negative electrode, positive electrode, electrolyte, and polyolefin microporous membrane are assembled into a soft-pack lithium-ion battery by winding, and the battery is sealed with commonly used tabs and aluminum-plastic film. The electrolyte is a 1M LiPF6 / (EC+DEC, 1:1) commercial electrolyte.
[0037] In the zero-strain carbon anode material obtained in Example 2, Al is anchored on graphite in the form of single atoms. No phase transition (solid solution mechanism) occurs during the entire charge-discharge process, and the lattice does not shrink / stretch, indicating the intrinsic zero-strain characteristics of the prepared anode material.
[0038] The prepared lithium-ion battery showed almost no capacity decay after 2000 cycles, indirectly demonstrating its intrinsic zero-strain characteristics.
[0039] Example 3 A method for preparing a zero-strain carbon anode material includes the following steps: (1) 20g of material with a specific surface area of 1m² 2 Mixture A is obtained by mixing layered waste cathode graphite with a particle size of 10nm-500um with 0.1g SiCl4.
[0040] (2) The mixture A was sintered at 1600℃ for 1 hour to obtain the zero-strain carbon anode material prepared from the waste cathode of electrolytic aluminum.
[0041] A method for preparing a lithium-ion battery, comprising: (1) The 240 mg zero-strain carbon anode material, 30 mg PVDF binder, and 30 mg superconducting carbon black powder conductive agent prepared above were evenly dispersed in 0.6 ml N-methylpyrrolidone (NMP) and coated onto a 12 μm copper foil current collector with a coating amount of 10 mg / cm. 2 Then, it is vacuum dried to produce a negative electrode sheet.
[0042] (2) Using superconducting carbon black as a conductive agent, PVDF as a binder, and NMP as a solvent, after stirring evenly, LiFePO4, the positive electrode active material, was added to obtain a mixture, which was then coated onto the surface of a 10μm Al foil with a coating amount of 21mg / cm.2 The positive electrode is then fabricated. The solid component of the mixture contains 90 wt.% lithium cobalt oxide (LiNi). 0.8 Co 0.1 Mn 0.1 O2), 5 wt.% binder PVDF and 5 wt.% conductive carbon black.
[0043] (3) The negative electrode, positive electrode, electrolyte, and polyolefin microporous membrane are assembled into a soft-pack lithium-ion battery by winding, and the battery is sealed with commonly used tabs and aluminum-plastic film. The electrolyte is a 1M LiPF6 / (EC+DEC, 1:1) commercial electrolyte.
[0044] In the zero-strain carbon anode material obtained in Example 3, Al is anchored on graphite in the form of single atoms. No phase transition (solid solution mechanism) occurs during the entire charge-discharge process, and the lattice does not shrink / stretch, indicating that the prepared anode material has intrinsic zero-strain characteristics.
[0045] The prepared lithium-ion battery showed almost no capacity decay after 2000 cycles, indirectly demonstrating its intrinsic zero-strain characteristics.
[0046] Comparative Example 1 A method for preparing a carbon anode material includes the following steps: (1) 20g of material with a specific surface area of 1m² 2 / g of graphite from waste cathodes of electrolytic aluminum with a particle size of 10nm-500um was sintered at 1200℃ for 8 hours to obtain carbon anode material prepared from waste cathodes of electrolytic aluminum.
[0047] A method for preparing a lithium-ion battery, comprising: (1) The 160 mg carbon anode material, 20 mg PVDF binder and 20 mg superconducting carbon black powder conductive agent prepared above were evenly dispersed in 0.4 ml N-methylpyrrolidone (NMP) and coated onto a 12 μm copper foil current collector with a coating amount of 10 mg / cm. 2 Then, it is vacuum dried to produce a negative electrode sheet.
[0048] (2) Using superconducting carbon black as a conductive agent, PVDF as a binder, and NMP as a solvent, after stirring evenly, LiFePO4, the positive electrode active material, was added to obtain a mixture, which was then coated onto the surface of a 10μm Al foil with a coating amount of 21mg / cm. 2 The positive electrode is then formed. The solid components of the mixture include 90 wt.% LiFePO4, 5 wt.% PVDF binder, and 5 wt.% conductive carbon black.
[0049] (3) The negative electrode, positive electrode, electrolyte, and polyolefin microporous membrane are assembled into a soft-pack lithium-ion battery by winding, and the battery is sealed with commonly used tabs and aluminum-plastic film. The electrolyte is a 1M LiPF6 / (EC+DEC, 1:1) commercial electrolyte.
[0050] The specific capacity of the prepared lithium-ion battery decreased significantly after 2000 cycles, indicating that it does not have intrinsic zero-strain characteristics.
[0051] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.
Claims
1. A method for preparing a zero-strain carbon anode material, characterized in that: Includes the following steps: (1) Mixing waste aluminum cathode graphite with substance A to obtain mixture A, wherein substance A is an Al precursor and / or a Si precursor; (2) Sinter the mixture A to obtain the zero-strain carbon anode material prepared from the waste cathode of electrolytic aluminum.
2. The method for preparing the zero-strain carbon anode material as described in claim 1, characterized in that: The Al precursor is at least one selected from AlCl3, aluminum oxide, aluminum hydroxide, aluminum-based metal-organic frameworks, aluminum isopropoxide, aluminum sec-butoxide, aluminum ethoxide, trimethylaluminum, and triethylaluminum; the Si precursor is silicon tetrachloride, sodium silicate, tetraethyl orthosilicate, dimethyldichlorosilane, aminosilane, Si3N4, Si, SiO2, SiO, and SiO2. x At least one of them.
3. The method for preparing the zero-strain carbon anode material as described in claim 1, characterized in that: The particle size of the waste cathode graphite from electrolytic aluminum is 10nm-500um.
4. The method for preparing the zero-strain carbon anode material as described in claim 1, characterized in that: The sintering temperature is 700-1600℃ and the time is 1-12h.
5. The method for preparing the zero-strain carbon anode material as described in claim 1, characterized in that: The mass ratio of the waste cathode graphite from electrolytic aluminum to substance A is (20-100):(0.1-2).
6. The zero-strain carbon anode material prepared by the method for preparing zero-strain carbon anodes according to any one of claims 1-5.
7. The zero-strain carbon anode material as described in claim 6, characterized in that: This includes carbon materials and Al and / or Si single atoms between carbon layers.
8. A negative electrode, characterized in that: It includes a negative electrode current collector and a negative electrode active material layer, wherein the negative electrode active material layer is disposed on at least one surface of the negative electrode current collector, and the negative electrode active material layer includes the zero-strain carbon negative electrode material of claim 6.
9. The negative electrode as described in claim 8, characterized in that: The negative electrode active material layer also includes a binder and a conductive agent.