Zinc metal negative electrode material with super-long cycle life and preparation method thereof

Abstract

This invention discloses a zinc metal anode material with ultra-long cycle life and its preparation method. The zinc metal anode material consists of a nanocrystalline zinc anode substrate and a hard nitride solid electrolyte interface layer. The nanocrystalline zinc anode is prepared by high-pressure torsion or low-temperature cold rolling to obtain a nanocrystalline zinc anode with a grain size of 40-500 nm. The hard nitride solid electrolyte interface layer is generated in situ on the nanocrystalline zinc anode by pulsed laser deposition to obtain a nitride interface layer with a grain size of 20-80 nm, a layer thickness of 100-800 nm, and a hardness greater than 12 GPa, thus obtaining a nanocrystalline zinc metal anode with this interface layer. In an aqueous zinc-ion battery system, the zinc metal anode prepared by this invention achieves a cycle life of 10 mA / cm². 2 It exhibits a cycle life exceeding 2700 cycles at high current densities, with a coulombic efficiency of 99.6%. This invention aims to improve the electrochemical reversibility and cycle life of zinc-ion batteries, with low material cost and simple preparation process, promoting the practical development of commercial aqueous zinc-ion batteries.

Description

Technical Field

[0001] This invention belongs to the field of zinc-ion battery technology, and particularly relates to a zinc metal anode material with ultra-long cycle life and its preparation method. Background Technology

[0002] Aqueous zinc-ion batteries boast a high theoretical capacity (820 mAh g). -1 5851 mAh cm -3 With its advantages such as intrinsic safety, low material cost, and environmental friendliness, zinc is considered an ideal candidate for next-generation grid-scale energy storage systems. However, its commercial application is still limited by the core bottleneck of insufficient cycle life: uneven deposition on the zinc anode side causes dendrite growth and surface side reactions (such as hydrogen evolution and corrosion), which severely limits cycle stability and zinc deposition / stripping reversibility.

[0003] To address the aforementioned challenges, researchers have proposed various zinc metal anode design strategies. For example, Zhang Zhen et al. constructed a zinc anode with a single (002) texture using electrodeposition, which effectively induced the preferred orientation deposition of zinc ions (CN202410274992); Zhang Chaofeng et al. employed an in-situ electrodeposition strategy to construct a dense covalent triazine framework protective film on the surface of the zinc anode, achieving a cycle life exceeding 110 h (CN202411795634). Although these strategies effectively improved the battery cycle life, the micron-sized zinc grains present in the modified zinc anode and the low mechanical strength of the protective layer limited the long-term service stability of the battery. Therefore, further optimizing the crystal microstructure of the zinc anode, while constructing an artificial solid electrolyte interface layer with both excellent electrochemical stability and strong mechanical properties, has become a key measure to overcome the aforementioned bottlenecks and achieve the deep industrialization of zinc-ion batteries. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a zinc metal anode material with ultra-long cycle life and its preparation method. A nanocrystalline zinc anode substrate is prepared by subjecting high-purity zinc sheets to intense plastic deformation using high-pressure torsion or low-temperature cold rolling. This anode significantly accelerates zinc deposition kinetics and homogenizes the electric field distribution by introducing numerous active grain boundaries, achieving ordered deposition. Simultaneously, it mitigates volume changes caused by deposition / stripping, maintaining electrode structural stability. Subsequently, a hard nitride solid electrolyte interface layer is generated in situ on the surface of the nanocrystalline zinc anode substrate using pulsed laser deposition technology. The ultra-high hardness (greater than 12 GPa) of this layer effectively inhibits dendrite growth, guiding it to undergo planarization plastic deformation. It also provides numerous zinc adsorption sites and lowers the nucleation barrier, promoting uniform zinc nucleation and suppressing side reactions. Therefore, the zinc metal anode material obtained based on the above exhibits ultra-long cycle life and excellent electrochemical reversibility.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A zinc metal anode material with ultra-long cycle life is disclosed, comprising a nanocrystalline zinc anode substrate and a hard nitride solid electrolyte interface layer. The nanocrystalline zinc anode substrate has a grain size of 40–500 nm; the hard nitride solid electrolyte interface layer has a grain size of 20–80 nm, a layer thickness of 100–800 nm, and a nanoindentation hardness greater than 12 GPa. The nitride is selected from zirconium nitride, titanium nitride, boron nitride, or silicon nitride. This type of material combines high mechanical strength with excellent chemical stability, physically suppressing dendrite growth and effectively preventing interfacial side reactions.

[0006] The zinc metal anode material has a strength of 1~20 mA / cm 2 They all exhibited cycle life exceeding 1500 cycles at current densities; for example, at 10 mA / cm². 2 The negative electrode has a cycle life of over 2700 cycles, and the coulomb efficiency remains at 99.6%.

[0007] This invention provides a method for preparing a zinc metal anode material with an ultra-long cycle life, comprising the following steps: 1) Using a high-pressure torsion method or a low-temperature cold rolling method, zinc sheets with a purity >99.9% are placed in a pressing mold, and then the zinc sheets are subjected to high-pressure torsion or low-temperature cold rolling to cause them to undergo severe plastic deformation, thus obtaining a nanocrystalline zinc anode substrate; 2) Fix the nanocrystalline zinc anode on the heating stage and adjust the distance between the nitride target and the nanocrystalline zinc anode substrate; pre-pump the gas pressure in the reaction chamber to 1×10⁻⁶. -8 After the torsion phase, high-purity nitrogen gas is slowly introduced while the temperature of the heating stage is controlled at 20-35°C. Subsequently, a KrF2 excimer laser with a wavelength of 248 nm is activated, and pulsed laser is output at a frequency of 6-10 Hz under a constant laser energy of 500-850 mJ. After focusing, the laser bombards the nitride target, causing it to transform from a solid phase to a plasma state and deposit a hard nitride solid electrolyte interface layer on the surface of the nanocrystalline zinc anode substrate. The deposition time is controlled at 10-40 min. After deposition, nitrogen gas is introduced, and the substrate is kept in situ at 20-35°C for 30 min before being cooled to room temperature to obtain a nanocrystalline zinc anode material with a hard nitride solid electrolyte interface layer, which is the zinc metal anode material with ultra-long cycle life.

[0008] Preferably, the high-pressure torsion method involves placing zinc sheets with a purity >99.9% in a pressing mold, subjecting the zinc sheets to high-pressure torsion at an ambient temperature below 40°C, controlling the pressure at 6-12 tons, the rotation speed at 0.2-0.8 rpm, and the number of torsion cycles at 5-10. This method ensures continuous plastic flow under shear without cracking through high hydrostatic pressure, and effectively suppresses recrystallization through low temperature and extremely gentle strain, achieving nanocrystalline homogenization of the zinc matrix.

[0009] Preferably, the low-temperature cold rolling method involves rolling at a temperature below -230°C and a cumulative strain greater than 2.2. The low-temperature environment effectively inhibits the dynamic recrystallization of the zinc matrix, and the high cumulative strain induces the fragmentation of the original grains to form a nanocrystalline structure.

[0010] Preferably, the distance between the nitride target and the nanocrystalline zinc anode substrate is adjusted to 5~10 cm to ensure the uniformity of the large-area film formation of the deposited layer, while controlling the target-substrate distance to regulate the grain size and crystal texture intensity of the deposited layer.

[0011] Preferably, high-purity nitrogen gas is slowly introduced during deposition until the pressure reaches 1.0 × 10⁻⁶. -3 ~1.0×10 -1 Torr can prevent the formation of nitrogen vacancies to ensure the high chemical purity and structural integrity of the deposited layer.

[0012] Preferably, nitrogen gas is introduced to 1-10 Torr after deposition to ensure a nitrogen-rich environment during the cooling stage to suppress secondary desorption of nitrogen and repair residual nitrogen vacancies in the original deposition layer; the high-pressure environment can achieve uniform heat conduction, thereby relieving interfacial thermal stress and preventing cracking of the deposition layer.

[0013] The beneficial effects of this invention are as follows: The zinc metal anode material of this invention exhibits an ultra-long cycle life and excellent electrochemical reversibility, with low material cost. Its preparation method first uses high-pressure torsion or low-temperature cold rolling to nanoscale the zinc anode grains (40~500 nm). By introducing a large number of active grain boundaries, the electrochemical reaction kinetics can be significantly accelerated and the electric field distribution homogenized, promoting ordered metal deposition. Simultaneously, it can alleviate volume deformation caused by deposition / stripping, which is beneficial for maintaining electrode stability. Subsequently, a hard nitride solid electrolyte interface layer is constructed in situ on the surface of the nanocrystalline zinc anode using pulsed laser deposition technology. The nanoscale grain size (20~80 nm) and high hardness (>12.0 GPa) of this layer effectively inhibit dendrite growth, guide its planarization plastic deformation, reduce the nucleation barrier, promote uniform nucleation and deposition, and suppress side reactions. The preparation process of this invention is simple and can effectively promote the industrialization of commercial zinc-ion batteries. Attached Figure Description

[0014] Figure 1In the embodiments of the present invention, a and b are micromorphological diagrams of the nanocrystalline zinc anode substrate (average grain size of ~100 nm, named Zn_NCs_100) and the hard zirconium nitride solid electrolyte interface layer (average grain size of ~20 nm, named ZrN_20) with ultra-long cycle life. Figure 2 The image shows the X-ray diffraction (XRD) pattern of the zinc metal anode material (Zn_NCs_100@ZrN_20) with ultra-long cycle life in an embodiment of the present invention. Figure 3 This is a nanoindentation hardness diagram of the zinc metal anode material (Zn_NCs_100@ZrN_20) with ultra-long cycle life in an embodiment of the present invention; Figure 4 The electrochemical impedance spectroscopy of the commercial zinc foil anode (Zn foil) and the zinc metal anode (Zn_NCs_100@ZrN_20) with ultra-long cycle life are shown in the embodiments of the present invention. Figure 5 In this embodiment of the invention, a commercial zinc foil anode (Zn foil) and a zinc metal anode (Zn_NCs_100@ZrN_20) with ultra-long cycle life are used at 10 mA / cm 2 Cyclic performance at current density; Detailed Implementation The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions herein are used to explain the invention but are not intended to limit it. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. In the illustrated embodiments, zirconium nitride is selected as a representative material for the hard nitride solid electrolyte interface layer. However, the scope of protection of the present invention is not limited to zirconium nitride; the hard nitride solid electrolyte interface layer may also include titanium nitride, boron nitride, or silicon nitride.

[0015] This invention discloses a zinc metal anode material with ultra-long cycle life and its preparation method. The zinc metal anode material consists of a nanocrystalline zinc anode substrate and a hard nitride solid electrolyte interface layer. The nanocrystalline zinc anode is prepared by high-pressure torsion or low-temperature cold rolling to obtain a nanocrystalline zinc anode with a grain size of 40-500 nm. The hard nitride solid electrolyte interface layer is generated in situ on the nanocrystalline zinc anode by pulsed laser deposition. By controlling the intracavity gas pressure, deposition time, and laser energy, a nitride interface layer with a grain size of 20-80 nm, a layer thickness of 100-800 nm, and a hardness greater than 12 GPa is obtained, thus obtaining a nanocrystalline zinc metal anode with this interface layer. In an aqueous zinc-ion battery system, the zinc metal anode prepared by this invention achieves a cycle life of 10 mA / cm². 2 It exhibits a service life of over 2700 cycles at high current densities and a coulomb efficiency of 99.6%.

[0016] Example 1 A high-pressure torsion method was used to place zinc sheets with a purity >99.9% in a pressing mold. The ambient temperature was below 40℃, the pressure was set to 12 tons, and the rotation speed was set to 0.2 rpm. The zinc sheets were subjected to high-pressure torsion for 10 cycles, which yielded a nanocrystalline zinc anode substrate (Zn_NCs_100) with an average grain size of ~100 nm.

[0017] The nanocrystalline zinc anode substrate was fixed on the heating stage, and the distance between the nitride target and the substrate was adjusted to 10 cm; the gas pressure in the reaction chamber was pre-evacuated to 1 × 10⁻⁶. -8 After Torr, high-purity nitrogen gas is slowly introduced until the concentration reaches 1.0 × 10⁻⁶. -3 The temperature of the heating stage was controlled at 20°C. Then, the KrF2 excimer laser was activated, and pulsed laser was output at a frequency of 10 Hz at a constant laser energy of 500 mJ for a deposition time of 10 min. After deposition, nitrogen gas was introduced to 1.0 Torr, and the layer was kept in situ at 20°C for 120 min before being cooled to room temperature, thus obtaining a zirconium nitride solid electrolyte interface layer (ZrN_20) with an average grain size of ~20 nm and a layer thickness of ~400 nm. Finally, a zinc metal anode material with ultra-long cycle life (Zn_NCs_100@ZrN_20) was obtained.

[0018] Example 2 A high-pressure torsion method was used to place zinc sheets with a purity >99.9% in a pressing mold. The ambient temperature was below 40℃, the pressure was set to 10 tons, and the rotation speed was set to 0.4 rpm. The zinc sheets were subjected to high-pressure torsion for 8 cycles, which yielded a nanocrystalline zinc anode substrate (Zn_NCs_200) with an average grain size of ~200 nm.

[0019] The nanocrystalline zinc anode substrate was fixed on the heating stage, and the distance between the nitride target and the substrate was adjusted to 8 cm; the gas pressure in the reaction chamber was pre-evacuated to 1 × 10⁻⁶. -8 After Torr, high-purity nitrogen gas is slowly introduced until the pressure reaches 4.0 × 10⁻⁶. -2 The temperature of the heating stage was controlled at 25°C. Then, the KrF2 excimer laser was started, and pulsed laser was output at a frequency of 8 Hz at a constant laser energy of 600 mJ for a deposition time of 20 min. After deposition, nitrogen gas was introduced to 2.0 Torr, and the temperature was kept in situ at 25°C for 200 min before being cooled to room temperature, thus obtaining a zirconium nitride solid electrolyte interface layer (ZrN_45) with an average grain size of ~45 nm and a layer thickness of ~600 nm. Finally, a zinc metal anode material with ultra-long cycle life (Zn_NCs_100@ZrN_45) was obtained.

[0020] Example 3 A high-pressure torsion method was used to place zinc sheets with a purity >99.9% in a pressing mold. The ambient temperature was below 40℃, the pressure was set to 8 tons, and the rotation speed was set to 0.6 rpm. The zinc sheets were subjected to high-pressure torsion for 6 cycles, which yielded a nanocrystalline zinc anode substrate (Zn_NCs_350) with an average grain size of ~350 nm.

[0021] The nanocrystalline zinc anode substrate was fixed on the heating stage, and the distance between the nitride target and the substrate was adjusted to 6 cm; the gas pressure in the reaction chamber was pre-evacuated to 1 × 10⁻⁶. -8 After Torr, high-purity nitrogen gas is slowly introduced until the pressure reaches 8.0 × 10⁻⁶. -2 The temperature of the heating stage was controlled at 30°C. Then, the KrF2 excimer laser was activated, and pulsed laser was output at a frequency of 8 Hz with a constant laser energy of 750 mJ for a deposition time of 30 min. After deposition, nitrogen gas was introduced to 5 Torr, and the layer was kept in situ at 30°C for 300 min before being cooled to room temperature, thus obtaining a zirconium nitride solid electrolyte interface layer (ZrN_60) with an average grain size of ~60 nm and a layer thickness of ~800 nm. Finally, a zinc metal anode material with ultra-long cycle life (Zn_NCs_100@ZrN_60) was obtained.

[0022] Example 4 A high-pressure torsion method was used to place zinc sheets with a purity >99.9% in a pressing mold. The ambient temperature was below 40℃, the pressure was set to 8 tons, and the rotation speed was set to 0.8 rpm. The zinc sheets were subjected to high-pressure torsion for 5 cycles, which yielded a nanocrystalline zinc anode substrate (Zn_NCs_500) with an average grain size of ~500 nm.

[0023] The nanocrystalline zinc anode substrate was fixed on the heating stage, and the distance between the nitride target and the substrate was adjusted to 5 cm; the gas pressure in the reaction chamber was pre-evacuated to 1 × 10⁻⁶. -8 After Torr, high-purity nitrogen gas is slowly introduced until the concentration reaches 1.0 × 10⁻⁶. -1 The temperature of the heating stage was controlled at 35°C. Then, the KrF2 excimer laser was activated, and pulsed laser was output at a frequency of 6 Hz at a constant laser energy of 850 mJ for a deposition time of 40 min. After deposition, nitrogen gas was introduced to 10 Torr, and the layer was kept in situ at 35°C for 360 min before being cooled to room temperature, thus obtaining a zirconium nitride solid electrolyte interface layer (ZrN_80) with an average grain size of ~80 nm and a layer thickness of ~800 nm. Finally, a zinc metal anode material with ultra-long cycle life (Zn_NCs_100@ZrN_80) was obtained.

[0024] like Figure 1 In Figure 'a' and 'b', the microstructures of the nanocrystalline zinc anode substrate (Zn_NCs_100) and the zirconium nitride solid electrolyte interface layer (ZrN_20) with ultra-long cycle life, respectively, are observed. In the Zn_NCs_100 anode substrate, a dense distribution of nanocrystalline zinc can be observed, with an average grain size of ~100 nm and uniform grain size. The morphology of ZrN_20 shows a highly dense and uniform distribution of nanocrystalline grains, with an average grain size of ~20 nm.

[0025] like Figure 2 The XRD pattern of the zinc metal anode material (Zn_NCs_100@ZrN_20) with ultra-long cycle life shows that the characteristic diffraction peaks of Zn and ZrN can be observed simultaneously, and no other impurity peaks are observed, which confirms the successful construction of the zirconium nitride artificial solid electrolyte interface layer.

[0026] like Figure 3 The nanoindentation hardness diagram of the zinc metal anode material (Zn_NCs_100@ZrN_20) with ultra-long cycle life shows that the zirconium nitride interface layer endows the anode surface with extremely high hardness (~16.0 GPa), which can provide strong mechanical support to resist high stress at dendrite tips and induce planarization plastic deformation of the deposited metal, thereby improving the cycle life of the anode.

[0027] like Figure 4Electrochemical impedance spectroscopy (EIS) of commercial zinc foil anode (Zn foil) and zinc metal anode material with ultra-long cycle life (Zn_NCs_100@ZrN_20) shows that the charge interface transfer impedance of Zn_NCs_100@ZrN_20 is significantly reduced compared to Zn foil. This indicates that the charge transfer energy barrier at the anode / electrolyte interface is lowered, which further enhances the reaction kinetics and is conducive to achieving efficient and orderly metal deposition behavior.

[0028] Commercial zinc foil anode (Zn foil) and zinc metal anode (Zn_NCs_100@ZrN_20) with ultra-long cycle life were cut into 12 mm diameter circular electrodes as anodes. 2M ZnSO4 aqueous solution was used as electrolyte. Asymmetric batteries were assembled with 12 mm diameter circular titanium electrodes as positive electrodes and glass fiber as separator for cycle charge and discharge testing.

[0029] like Figure 5 The cycling performance diagrams for commercial zinc foil anodes (Zn foil) and zinc metal anode materials with ultra-long cycle life (Zn_NCs_100@ZrN_20) show that at 10 mA / cm²... 2 At high current densities, the battery corresponding to the Zn foil anode can only cycle 300 times; in contrast, the battery corresponding to Zn_NCs_100@ZrN_20 exhibits a cycle life of over 2700 cycles and a coulombic efficiency of 99.6%.

[0030] The embodiments described above are merely preferred embodiments of the present invention and do not constitute a limitation on the scope of protection of this technical solution. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this invention should be included within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A zinc metal anode material with an ultra-long cycle life, characterized in that: It consists of a nanocrystalline zinc anode substrate and a hard nitride solid electrolyte interface layer; wherein the grain size of the nanocrystalline zinc anode substrate is 40~500 nm; the grain size of the hard nitride solid electrolyte interface layer is 20~80 nm, the layer thickness is 100~800 nm, and the nanoindentation hardness is greater than 12 GPa.

2. The zinc metal anode material with ultra-long cycle life according to claim 1, characterized in that: in, The nitrides are zirconium nitride, titanium nitride, boron nitride, or silicon nitride.

3. The zinc metal anode material with ultra-long cycle life according to claim 1, characterized in that: The zinc metal anode material has a strength of 1~20 mA / cm 2 They all exhibited a cycle life of over 1500 cycles at current densities.

4. A method for preparing a zinc metal anode material with ultra-long cycle life as described in any one of claims 1 to 3, characterized in that, Includes the following steps: 1) Using a high-pressure torsion method or a low-temperature cold rolling method, zinc sheets with a purity >99.9% are placed in a pressing mold and subjected to high-pressure torsion or low-temperature cold rolling to cause severe plastic deformation, thus obtaining a nanocrystalline zinc anode substrate; 2) Fix the nanocrystalline zinc anode substrate on the heating stage and adjust the distance between the nitride target and the nanocrystalline zinc anode substrate; pre-evacuate the reaction chamber pressure to 1×10⁻⁶. -8 After torsion, high-purity nitrogen gas is slowly introduced while the temperature of the heating stage is controlled at 20-35°C. Then, a KrF2 excimer laser with a wavelength of 248 nm is activated, and pulsed laser is output at a frequency of 6-10 Hz under a constant laser energy of 500-850 mJ. After focusing, the laser bombards the nitride target, causing it to transform from a solid state to a plasma state and deposit a hard nitride solid electrolyte interface layer on the surface of the nanocrystalline zinc anode substrate. The deposition time is controlled at 10-40 min. After deposition, nitrogen gas is introduced, and the substrate is kept in situ at 20-35°C for 120-360 min before being cooled to room temperature to obtain a nanocrystalline zinc anode material with a hard nitride solid electrolyte interface layer, which is the zinc metal anode material with ultra-long cycle life.

5. The preparation method according to claim 4, characterized in that: The high-pressure torsion method is as follows: place zinc sheets with a purity >99.9% in a pressing mold, and subject the zinc sheets to high-pressure torsion in an environment with a temperature below 40℃. Control the pressure to 6~12 tons, the rotation speed to 0.2~0.8 rpm, and the number of torsion cycles to 5~10 cycles.

6. The preparation method according to claim 4, characterized in that: The low-temperature cold rolling method is a rolling temperature below -230℃ and a cumulative strain greater than 2.

2.

7. The preparation method according to claim 4, characterized in that: The distance between the nitride target and the nanocrystalline zinc anode substrate was adjusted to 5~10 cm.

8. The preparation method according to claim 4, characterized in that: During deposition, high-purity nitrogen gas is slowly introduced until the pressure reaches 1.0 × 10⁻⁶. -3 ~1.0×10 -1 Torr.

9. The preparation method according to claim 4, characterized in that: After deposition, nitrogen gas is introduced to 1-10 Torr.

Images