阅读说明：本技术 一种等离子体改性钠超离子导体型固态电解质的方法 (Method for modifying sodium super-ion conductor type solid electrolyte by plasma ) 是由 梁风 候敏杰 张涛 石祥刚 杨斌 向孙祖 戴永年 于 2021-08-24 设计创作，主要内容包括：本发明公开了一种等离子体改性钠超离子导体型固态电解质的方法,所述方法包括：对钠超离子导体型固态电解质颗粒进行等离子体改性处理,得到活化钠超离子导体型固态电解质颗粒；按照预订的比例称取聚合物与所述活化钠超离子导体型固态电解质颗粒,将所述聚合物与所述活化钠超离子导体型固态电解质颗粒溶于有机溶剂中得到混合溶液,然后将所述混合溶液浇注到预设模具中,再进行干燥以去除所述有机溶剂并成形为复合固态电解质膜,从所述预设模具中取出所述复合固态电解质膜并进行辊压,得到辊压处理后的复合固态电解质膜。本发明方法生产周期短、成本低、可大规模商业化,进一步实现固态电解质在商业化中的应用。(The invention discloses a method for modifying a sodium super-ion conductor type solid electrolyte by using plasma, which comprises the following steps: carrying out plasma modification treatment on the sodium super-ion conductor type solid electrolyte particles to obtain activated sodium super-ion conductor type solid electrolyte particles; weighing a polymer and the activated sodium super ionic conductor type solid electrolyte particles according to a preset proportion, dissolving the polymer and the activated sodium super ionic conductor type solid electrolyte particles in an organic solvent to obtain a mixed solution, then pouring the mixed solution into a preset mold, drying to remove the organic solvent and form a composite solid electrolyte membrane, taking out the composite solid electrolyte membrane from the preset mold, and rolling to obtain the composite solid electrolyte membrane after rolling treatment. The method has short production period and low cost, can be commercialized in a large scale, and further realizes the application of the solid electrolyte in commercialization.)

1. A method for modifying a sodium super-ionic conductor type solid electrolyte by using plasma is characterized by comprising the following steps:

plasma modification treatment: and carrying out plasma modification treatment on the sodium super-ionic conductor type solid electrolyte particles to obtain activated sodium super-ionic conductor type solid electrolyte particles.

Preparing a composite solid electrolyte: weighing a polymer and the activated sodium super ionic conductor type solid electrolyte particles according to a preset proportion, dissolving the polymer and the activated sodium super ionic conductor type solid electrolyte particles in an organic solvent to obtain a mixed solution, then pouring the mixed solution into a preset mold, drying to remove the organic solvent and form a composite solid electrolyte membrane, taking out the composite solid electrolyte membrane from the preset mold, and rolling to obtain the composite solid electrolyte membrane after rolling treatment.

2. The method of claim 1, wherein: in the step of performing plasma modification treatment on the sodium super-ion conductor type solid electrolyte particles, the plasma modification treatment adopts a preset plasma atmosphere, a preset gas flow rate, a preset voltage, a preset current and a first preset time, the preset plasma atmosphere is one or more of nitrogen, oxygen, argon, a nitrogen-oxygen mixed gas, a nitrogen-argon mixed gas and air, the pressure of the preset plasma atmosphere is atmospheric pressure, the preset voltage is the voltage applied to the sodium super-ion conductor type solid electrolyte particles, the voltage range is 10V-150V, the preset current is the current applied to the sodium super-ion conductor type solid electrolyte particles, the current range is 0.2A-2A, and the first preset time is 1 min-60 min.

3. The method of claim 1, wherein: the preset proportion is the mass proportion of the polymer to the activated sodium super-ionic conductor type solid electrolyte particles, and the mass proportion ranges from 10 wt% to 80 wt%.

4. The method of claim 1, wherein: the polymer category comprises at least one of polyethylene oxide, polyvinylidene fluoride-co-hexafluoropropylene and polyethylene glycol.

5. The method of claim 1, wherein: the organic solvent comprises one or two of acetone, N-dimethylformamide, acetonitrile and N-methylpyrrolidone.

6. The method of claim 1, wherein: in the step of dissolving the polymer and the activated sodium super ionic conductor type solid electrolyte particles in the organic solvent to obtain a mixed solution, the polymer and the activated sodium super ionic conductor type solid electrolyte particles are dissolved in the organic solvent and subjected to mechanical ball milling to obtain the mixed solution.

7. The method of claim 6, wherein: the mechanical ball milling is carried out at a preset mechanical ball milling rotating speed, and the preset mechanical ball milling rotating speed range is 150 r/min-400 r/min; the mechanical ball milling time is a second preset time, and the second preset time ranges from 5h to 48 h.

8. The method of claim 1, wherein: the step of pouring the mixed solution into a preset mold, and then drying to remove the organic solvent and form the composite solid electrolyte membrane includes: pouring the mixed solution into the preset mold, putting the preset mold into a vacuum drying oven, adjusting the temperature in the vacuum drying oven to a preset temperature, and keeping the preset temperature for a third preset time to obtain the composite solid electrolyte membrane; the third preset time ranges from 15h to 48 h; the preset temperature range is 40-100 ℃.

9. The method of claim 1, wherein: the thickness of the composite solid electrolyte membrane after the rolling treatment is 30-100 mu m.

10. A method for modifying a sodium super-ionic conductor type solid electrolyte by plasma comprises the following steps:

carrying out plasma activation treatment on the sodium super-ion conductor type solid electrolyte particles to obtain activated sodium super-ion conductor type solid electrolyte particles;

and obtaining a composite solid electrolyte membrane by using the activated sodium super ionic conductor type solid electrolyte particles, wherein the thickness of the composite solid electrolyte membrane is 30-100 mu m.

Technical Field

The invention relates to the field of new energy materials, in particular to a method for modifying a sodium super-ion conductor type solid electrolyte by using plasma.

Background

Driven by the strategic objective of the 'double-carbon' country, the optimization of an energy structure is accelerated, and the construction of a novel power system mainly based on new energy becomes a necessary trend. The development of novel energy materials and energy storage devices has important significance for promoting green transformation of energy, coping with extreme events, guaranteeing energy safety, promoting high-quality development of energy and realizing the aim of 'double carbon'.

The solid-state sodium ion battery is called as a green energy source facing the 21 st century, and compared with the traditional lithium battery, the solid-state sodium ion battery has the advantages of abundant raw material reserves, low production cost, high safety performance, large working environment temperature range, environmental friendliness and the like. The large-scale application of the solid sodium ion battery can meet the corresponding requirements of a novel power system, and becomes one of key supports of 'carbon peak reaching and carbon neutralization' in the field of energy.

In recent years, sodium metal negative electrodes have been considered as key negative electrode materials for next-generation high energy density solid-state sodium ion batteries due to their high specific mass capacity and low electrochemical potential. However, when sodium metal is used as a negative electrode, the growth of sodium dendrites can pierce a diaphragm to cause short circuit in the battery, so that the problems of thermal runaway, flammability, explosiveness and the like are caused, and the use of the solid electrolyte is hopeful to fundamentally solve the safety problem caused by the organic electrolyte.

In addition, solid-state electrolytes have several major advantages: 1) the safety is high, the leakage and flammability problems are avoided, and the packaging requirement of the battery pack is reduced; 2) a scalable electrochemical window; 3) high energy density. Therefore, the development of the solid-state sodium-ion battery not only has wide application prospect and is enough to cause revolutionary changes of energy storage devices and applications, but also has very important effect on national energy safety strategy. Solid-state sodium ion batteries are largely classified into inorganic solid-state electrolyte batteries, polymer batteries, and the like, according to the kind of solid-state electrolyte used. At present, many scientific and technical challenges are still faced in developing a solid-state sodium ion battery with excellent performance.

The composite solid electrolyte combines the polymer electrolyte and the inorganic solid electrolyte, has the unique advantages of small interface impedance, long cycle life, no memory function, light weight, flexibility, easy processing and the like, and is the key for realizing the miniaturization and the portability of the battery. However, the low room temperature ionic conductivity, poor film forming mechanical properties, high porosity, narrow electrochemical window, and poor compatibility with the interface between electrodes of such materials limit their application in solid-state sodium ion batteries. The surface energy of inorganic solid electrolyte particles is enhanced, the affinity of the inorganic solid electrolyte particles and a polymer interface is improved, and the composite solid electrolyte with uniform texture, low porosity and high ionic conductivity is obtained, which is a key problem to be solved for developing a high-performance all-solid-state sodium ion battery.

Disclosure of Invention

The invention aims to provide a method for modifying a sodium super-ionic conductor type solid electrolyte by using plasma, which is used for improving the surface energy of sodium super-ionic conductor type solid electrolyte particles, enhancing the interfacial affinity between the sodium super-ionic conductor type solid electrolyte particles and a polymer, obtaining a composite solid electrolyte with low porosity, safety, reliability, low cost and small interfacial impedance, and further optimizing the cycle life and the electrochemical performance of a solid sodium ion battery using the composite solid electrolyte.

In order to achieve the above object, an embodiment of the present invention provides a method for plasma modifying a sodium super ionic conductor type solid electrolyte, comprising the steps of:

plasma modification treatment: carrying out plasma modification treatment on the sodium super-ion conductor type solid electrolyte particles to obtain activated sodium super-ion conductor type solid electrolyte particles;

preparing a composite solid electrolyte: weighing a polymer and the activated sodium super ionic conductor type solid electrolyte particles according to a preset proportion, dissolving the polymer and the activated sodium super ionic conductor type solid electrolyte particles in an organic solvent to obtain a mixed solution, pouring the mixed solution into a preset mold, performing vacuum drying to remove the organic solvent and form a composite solid electrolyte membrane, taking out the composite solid electrolyte membrane from the preset mold, and performing rolling to obtain the rolled composite solid electrolyte membrane.

Compared with the prior art, in the method for plasma modification of the sodium super ionic conductor type solid electrolyte particles, plasma modification treatment is adopted to perform plasma activation treatment on the sodium super ionic conductor type solid electrolyte particles, so that the surface energy of the sodium super ionic conductor type solid electrolyte particles is increased, and the affinity between the sodium super ionic conductor type solid electrolyte particles and a polymer is improved. The prepared composite solid electrolyte has reduced porosity, increased ionic conductivity and improved agglomeration of sodium super ionic conductor type solid electrolyte particles. The lithium ion battery pack is applied to a solid sodium ion battery, and can reduce interface impedance, reduce battery polarization, inhibit growth of lithium dendrites, prolong the cycle life of the battery and improve the electrochemical performance of the battery pack. In addition, the process flow for preparing the plasma modified sodium super ionic conductor type solid electrolyte particles and the composite solid electrolyte is simple, the complex reaction process is basically not involved, and the energy consumption and the equipment investment are reduced. In addition, any process link of the invention basically does not generate three wastes, accords with the concept of green industry and is environment-friendly.

In some embodiments, the step of performing plasma modification treatment on the sodium super-ionic conductor type solid electrolyte particles adopts a preset plasma atmosphere, a preset gas flow rate, a preset voltage, a preset current and a first preset time, the preset plasma atmosphere is one of nitrogen, oxygen, argon, nitrogen-oxygen mixture, nitrogen-argon mixture and air, the pressure of the preset plasma atmosphere is atmospheric pressure, the preset voltage is a voltage applied to the sodium super-ionic conductor type solid electrolyte particles and a voltage range is 10V-150V, the preset current is a current applied to the sodium super-ionic conductor type solid electrolyte particles and a current range is 0.2A-2A, and the first preset time is 1 min-60 min. Specifically, the plasma activation treatment adopts the above preset plasma atmosphere, preset gas flow rate, preset voltage, preset current and first preset time, so that the sodium super-ionic conductor type solid electrolyte has high surface energy and excellent affinity with a polymer interface.

In some embodiments, the predetermined ratio is a mass ratio of the polymer to the activated sodium super ionic conductor-type solid state electrolyte particles, the mass ratio ranging from 10 wt.% to 80 wt.%. Specifically, according to the preset proportion, the porosity can be reduced, the polymer crystallization can be effectively inhibited, the glass transition temperature can be reduced, better mechanical property and ionic conductivity can be presented, the finally obtained composite solid electrolyte membrane has higher mechanical property and ionic conductivity, and the battery has better cycle performance.

In some embodiments, the polymeric species comprises at least one of polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyethylene glycol (PEG). Specifically, by adopting the polymer, the composite solid electrolyte membrane obtained finally has the advantages of low porosity, excellent ionic conductivity, mechanical property and electrochemical property due to the advantages of good electrochemical stability, high dielectric constant, good thermodynamic stability, a structure beneficial to rapid ion migration and the like.

In some embodiments, the organic solvent comprises one or both of acetone, N-Dimethylformamide (DMF), acetonitrile, N-methylpyrrolidone (NMP). Specifically, the solvent has good compatibility with the polymer, and the finally obtained composite solid electrolyte membrane has a better microstructure and mechanical properties.

In some embodiments, in the step of dissolving the polymer and the activated sodium super ionic conductor type solid electrolyte particles in the organic solvent to obtain a mixed solution, the polymer and the activated sodium super ionic conductor type solid electrolyte particles are dissolved in the organic solvent and subjected to mechanical ball milling to obtain the mixed solution. Specifically, the mechanical ball milling is performed at a predetermined mechanical ball milling rotation speed, the predetermined mechanical ball milling rotation speed range may be 150r/min to 400r/min, the mechanical ball milling time is a second preset time, and the second preset time range may be 5h to 48 h. Specifically, by adopting the mechanical ball milling at the rotating speed and time, the polymer and the activated sodium super ionic conductor type solid electrolyte particles can be dissolved in the organic solvent more uniformly, the generation of bubbles can be reduced, the crystal grains of the sodium super ionic conductor type solid electrolyte particles can be further refined, and the composite solid electrolyte can have smaller impedance, longer cycle performance and more excellent electrochemical performance.

In some embodiments, the step of pouring the mixed solution into a predetermined mold, and then drying to remove the organic solvent and form a composite solid electrolyte membrane includes: pouring the mixed solution into the preset mold, putting the preset mold into a vacuum drying oven, adjusting the temperature in the vacuum drying oven to a preset temperature, and keeping the preset temperature for a third preset time to obtain the composite solid electrolyte membrane; the third preset time ranges from 15h to 48 h; the preset temperature range is 40-100 ℃.

It can be understood that, in the method for plasma modifying the sodium super ionic conductor type solid electrolyte particles, the sodium super ionic conductor type solid electrolyte particles are subjected to plasma activation treatment by using plasma modification treatment, and are cast into a film, so that the sodium super ionic conductor type composite solid electrolyte film is enhanced in solid-solid interface compatibility, reduced in interface impedance and reduced in polarization of the battery, the cycle life of the solid battery using the composite solid electrolyte film can be prolonged, and the performance is excellent. Specifically, by adopting the third predetermined time and the preset temperature range, the finally obtained activated composite solid electrolyte membrane has a better microstructure and mechanical properties.

In some embodiments, the thickness of the composite solid electrolyte membrane after the rolling treatment is 30 μm to 100 μm, which can make the composite solid electrolyte membrane after the activation have better performance, such as better sodium ion transmission performance and better battery cycle performance.

Furthermore, the preparation methods of the plasma modified sodium super ionic conductor type solid electrolyte particles and the composite solid electrolyte have simple process flows, do not basically relate to complex reaction processes, and reduce the energy consumption and the equipment investment. In addition, any process link of the invention basically does not generate three wastes, accords with the concept of green industry and is environment-friendly.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic diagram of the steps of a method for plasma modification of sodium super ionic conductor type solid electrolyte particles provided by the present invention;

FIG. 2 is a schematic diagram of another process step for plasma modifying sodium super ionic conductor type solid state electrolyte particles provided by the present invention;

FIG. 3 is a Scanning Electron Microscope (SEM) image of a composite solid electrolyte prepared from unmodified sodium super ionic conductor type solid electrolyte particles obtained in the first embodiment of the present invention;

FIG. 4 is a Scanning Electron Microscope (SEM) image of composite solid electrolyte prepared by using the plasma modified sodium super ionic conductor type solid electrolyte particles obtained in the first embodiment of the invention

FIG. 5 is an X-ray diffraction pattern (XRD) of plasma modified/unmodified sodium super ionic conductor type solid state electrolyte particles obtained in a first practice of the invention;

FIG. 6 is an energy spectrum analysis (EDS) of unmodified sodium super ionic conductor type solid state electrolyte particles to prepare a composite solid state electrolyte according to a first embodiment of the present invention;

FIG. 7 is an energy spectrum analysis (EDS) of a composite solid electrolyte prepared from plasma-modified sodium super ionic conductor type solid electrolyte particles obtained in the first embodiment of the present invention;

FIG. 8 is a comparison of the cycle of a symmetrical cell (Na/composite solid electrolyte/Na) for preparing a composite solid electrolyte from solid electrolyte particles of the plasma modified/unmodified Na super ionic conductor type obtained in the first embodiment of the present invention;

FIG. 9 is a comparison of Electrochemical Impedance Spectroscopy (EIS) of composite solid electrolytes prepared by plasma modified/unmodified sodium super ionic conductor type solid electrolyte particles obtained in the first embodiment of the present invention;

FIG. 10 is a diagram of a cycle of a symmetrical cell (Na/composite solid electrolyte/Na) for preparing a composite solid electrolyte from plasma-modified Na-super-ionic conductor-type solid electrolyte particles obtained in a second embodiment of the present invention;

FIG. 11 is an Electrochemical Impedance Spectroscopy (EIS) of a composite solid electrolyte prepared from the plasma modified sodium super ionic conductor type solid electrolyte particles obtained in the third embodiment of the present invention.

Detailed Description

The invention will be described in more detail with reference to the following figures and examples, but the scope of the invention is not limited thereto.

As mentioned above, many scientific and technical challenges still face in developing a solid-state sodium ion battery with superior performance: for example, large interfacial (electrode/solid electrolyte) resistance, electrode material volume change, low loading of electrode active material, poor cycling stability, and the like. Among the many challenges, one of the important challenges to be solved is to increase the density of the solid electrolyte, reduce the porosity, and suppress the uneven deposition of lithium metal in the pores, and the key to overcome this challenge is to modify the surface of the inorganic solid electrolyte particles to increase the interfacial affinity between the inorganic solid electrolyte and the organic substance.

The molecular formula of the sodium super ionic conductor type solid electrolyte of the sodium super ionic conductor (NASICON) type solid electrolyte particles related to the embodiment of the invention is Na_xZr₂Si_x-1P_4-xO₁₂Wherein x is more than or equal to 1 and less than or equal to 4. Embodiments of the invention utilize plasmaThe modification function effectively improves the surface energy of the sodium super-ionic conductor type solid electrolyte particles, improves the interface affinity between the sodium super-ionic conductor type solid electrolyte particles and a polymer, reduces the porosity of the prepared composite solid electrolyte membrane, ensures uniform distribution of the sodium super-ionic conductor type solid electrolyte particles, promotes uniform deposition of lithium metal, and improves the stability and cycle life of the solid sodium ion battery.

Specifically, as shown in fig. 1, the method for plasma modification of sodium super ionic conductor type solid electrolyte particles provided by the invention comprises the following steps:

plasma modification treatment: carrying out plasma modification treatment on the sodium super-ion conductor type solid electrolyte particles to obtain activated sodium super-ion conductor type solid electrolyte particles;

preparing a composite solid electrolyte: weighing a polymer and the activated sodium super ionic conductor type solid electrolyte particles according to a preset proportion, dissolving the polymer and the activated sodium super ionic conductor type solid electrolyte particles in an organic solvent to obtain a mixed solution, then pouring the mixed solution into a preset mold, performing vacuum drying to remove the organic solvent and form a composite solid electrolyte membrane, taking out the composite solid electrolyte membrane from the preset mold, and performing rolling to obtain the rolled composite solid electrolyte membrane.

Compared with the prior art, in the method for plasma modification of the sodium super ionic conductor type solid electrolyte particles, plasma modification is adopted to perform plasma activation treatment on the sodium super ionic conductor type solid electrolyte particles, so that the porosity of the composite solid electrolyte prepared from the sodium super ionic conductor type solid electrolyte particles is reduced, the growth of lithium dendrites is inhibited, the interface impedance is reduced, the polarization of the battery is reduced, the cycle life of the composite solid electrolyte prepared from the plasma modified sodium super ionic conductor type solid electrolyte particles is prolonged, and the electrochemical performance is excellent. In addition, the method for modifying the sodium super-ionic conductor type solid electrolyte by using the plasma and the applied process flow are simple, the complex reaction process is basically not involved, and the energy consumption and the equipment investment are reduced. In addition, any process link of the invention basically does not generate three wastes, accords with the concept of green industry and is environment-friendly.

The step of subjecting the sodium super-ion conductor type solid electrolyte particles to plasma modification treatment includes: the method comprises the following steps of carrying out plasma modification treatment on sodium super-ion conductor type solid electrolyte particles, wherein the plasma modification treatment adopts a preset plasma atmosphere, a preset gas flow speed, a preset voltage, a preset current and a first preset time, the preset plasma atmosphere is one of nitrogen, oxygen, argon, nitrogen-oxygen mixed gas, nitrogen-argon mixed gas and air, the pressure of the preset plasma atmosphere is atmospheric pressure, the preset voltage is the voltage applied to the sodium super-ion conductor type solid electrolyte particles, the voltage range is 10V-150V, the preset current is the current applied to the sodium super-ion conductor type solid electrolyte particles, the current range is 0.2A-2A, and the first preset time is 1 min-60 min. Specifically, the plasma activation treatment adopts the above preset plasma atmosphere, preset gas flow rate, preset voltage, preset current and first preset time, so that the composite solid electrolyte has excellent micro-crystal structure, porosity, ionic conductivity and battery cycle performance.

In some embodiments, the predetermined ratio is a mass ratio of the polymer to the activated sodium super ionic conductor-type solid state electrolyte particles, the mass ratio ranging from 10 wt.% to 80 wt.%. Specifically, according to the preset proportion, the porosity can be effectively reduced, the polymer crystallization can be inhibited, the glass transition temperature can be reduced, the mechanical property and the ionic conductivity of the finally obtained sodium super-ion conductor type composite solid electrolyte membrane are high, and the battery has excellent cycle performance.

In some embodiments, the polymeric species comprises at least one of polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyethylene glycol (PEG). Specifically, by adopting the polymer, the composite solid electrolyte membrane finally obtained has the advantages of good electrochemical stability, high dielectric constant, good thermodynamic stability, a structure beneficial to rapid ion migration and the like, and has excellent porosity, ionic conductivity, mechanical property and electrochemical property.

In some embodiments, the organic solvent comprises one or both of acetone, N-Dimethylformamide (DMF), acetonitrile, N-methylpyrrolidone (NMP). Specifically, the solvent has good compatibility with the polymer, and the finally obtained composite solid electrolyte membrane has a better microstructure and mechanical properties.

In some embodiments, the polymer and the activated sodium super ionic conductor type solid state electrolyte particles are dissolved in the organic solvent and mechanically ball milled at the predetermined mechanical ball milling rotational speed, which is in a range of 150r/min to 400 r/min. Specifically, by adopting the mechanical ball milling at the above rotating speed, the polymer and the activated sodium super ionic conductor type solid electrolyte particles can be dissolved in the organic solvent mixture more uniformly, the generation of bubbles can be reduced, the crystal grains of the sodium super ionic conductor type solid electrolyte particles can be further refined, and the composite solid electrolyte can have smaller impedance, longer cycle performance and more excellent electrochemical performance.

Further, the method for plasma modification of the sodium super-ionic conductor type solid electrolyte provided by the invention can be briefly summarized as follows:

carrying out plasma activation treatment on the sodium super-ion conductor type solid electrolyte particles to obtain activated sodium super-ion conductor type solid electrolyte particles;

and obtaining the composite solid electrolyte membrane by using the activated sodium super ionic conductor type solid electrolyte particles.

It is to be understood that the step of performing plasma activation treatment on the sodium super ionic conductor type solid electrolyte particles to obtain activated sodium super ionic conductor type solid electrolyte particles may include a specific step of specifically adopting the plasma modification treatment shown in fig. 1. The step of obtaining the composite solid electrolyte membrane by using the activated sodium super ionic conductor type solid electrolyte particles may include the step of preparing the composite solid electrolyte shown in fig. 1, and will not be described in detail herein.

Specifically, the thickness of the composite solid electrolyte membrane may be 30 μm to 100 μm; it can be understood that, in the method for plasma modifying the sodium super ionic conductor type solid electrolyte particles, the sodium super ionic conductor type solid electrolyte particles are subjected to plasma activation treatment by using plasma modification treatment, and are cast into a film, so that the sodium super ionic conductor type composite solid electrolyte film is enhanced in solid-solid interface compatibility, reduced in interface impedance and reduced in polarization of the battery, the cycle life of the solid battery using the composite solid electrolyte film can be prolonged, and the performance is excellent. In addition, the thickness of the composite solid electrolyte membrane is 30-100 μm, so that the composite solid electrolyte membrane after activation has better performance, such as better sodium ion transmission performance and better battery cycle performance. Furthermore, the preparation methods of the plasma modified sodium super ionic conductor type solid electrolyte particles and the composite solid electrolyte have simple process flows, do not basically relate to complex reaction processes, and reduce the energy consumption and the equipment investment. In addition, any process link of the invention basically does not generate three wastes, accords with the concept of green industry and is environment-friendly.

The present invention will be described in detail below with reference to first to eighth embodiments.

First embodiment

(1) Plasma modification treatment: carrying out low-temperature plasma activation treatment on the sodium super-ion conductor type solid electrolyte particles for 5min under the condition of nitrogen with the gas flow rate of 10m/s, the working current of 1A and the voltage of 100V, and then cooling to room temperature to obtain activated sodium super-ion conductor type solid electrolyte particles;

(2) preparing a composite solid electrolyte: weighing PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles obtained in the step (1) according to a proportion of 20 wt.%, dissolving the PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles in acetone and N, N-dimethylformamide, mechanically ball-milling for 24 hours at a rotating speed of 250r/min to obtain a mixed solution, slowly pouring the mixed solution into a polytetrafluoroethylene mold, rolling to a thickness of 20 micrometers, and standing for 24 hours in a vacuum drying oven at a temperature of 80 ℃ to remove the organic solvent to obtain the composite solid electrolyte membrane.

In the present example, the PVDF-HFP based sodium super ionic conductor type composite solid electrolyte obtained by the plasma activation treatment was subjected to physical and electrochemical tests, and comparing the scanning electron microscope shown in fig. 3 and fig. 4, it can be seen that the surface cracks and the porosity of the PVDF-HFP based sodium super ionic conductor type composite solid electrolyte were reduced after the low temperature plasma activation treatment compared with the untreated PVDF. From FIG. 5, it was confirmed that the positions and intensities of diffraction peaks before and after the treatment were not significantly changed, and that the crystal structure of the sodium super-ion conductor was not changed by the plasma activation treatment. Comparing fig. 6 and fig. 7, it can be seen that the particle size and element distribution are more uniform and the agglomeration is significantly reduced after the low-temperature plasma activation treatment. From fig. 8 and 9, it can be seen that the polarization of the cell decreased from 0.85V to 0.55V, the cell could be stably cycled for 1800h or more, and the interface impedance decreased from 58 Ω to 24 Ω, compared to the untreated cell.

Second embodiment

(1) Plasma modification treatment: carrying out low-temperature plasma activation treatment on the sodium super-ion conductor type solid electrolyte particles for 1min under the condition of nitrogen with the gas flow rate of 10m/s, the working current of 2A and the voltage of 150V, and then cooling to room temperature to obtain activated sodium super-ion conductor type solid electrolyte particles;

(2) preparing a composite solid electrolyte: weighing PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles obtained in the step (1) according to a proportion of 80 wt.%, dissolving the PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles in acetone and N, N-dimethylformamide, mechanically ball-milling for 5 hours at a rotating speed of 400r/min to obtain a mixed solution, slowly pouring the mixed solution into a polytetrafluoroethylene mold, rolling to a thickness of 100 mu m, and standing in a vacuum drying oven at a temperature of 80 ℃ for 15 hours to remove the organic solvent to obtain the composite solid electrolyte membrane.

In this example, as shown in fig. 10, a symmetric battery with a composite solid electrolyte containing 80 wt.% of activated sodium super ionic conductor type solid electrolyte particles (Na/composite solid electrolyte/Na) can be cycled stably for over 2100h and has a stable polarization voltage of 0.5V.

Third embodiment

(1) Plasma modification treatment: carrying out low-temperature plasma activation treatment on the sodium super-ion conductor type solid electrolyte particles for 60min under the condition of nitrogen with the gas flow rate of 10m/s, the working current of 0.2A and the voltage of 10V, and then cooling to room temperature to obtain activated sodium super-ion conductor type solid electrolyte particles;

(2) preparing a composite solid electrolyte: weighing PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles obtained in the step (1) according to a proportion of 10 wt.%, dissolving the PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles in acetone and N, N-dimethylformamide, mechanically ball-milling for 48h at a rotating speed of 150r/min to obtain a mixed solution, slowly pouring the mixed solution into a polytetrafluoroethylene mold, rolling to a thickness of 30 mu m, and standing for 48h in a vacuum drying oven at a temperature of 40 ℃ to remove the organic solvent to obtain the composite solid electrolyte membrane.

In this example, an ac impedance test was performed on the composite solid electrolyte, and as shown in fig. 11, the composite solid electrolyte prepared based on the activated sodium super ionic conductor type solid electrolyte particles has a significant advantage of impedance reduction compared to the unmodified composite solid electrolyte, and the interface impedance is reduced from 58 Ω to 47 Ω.

Fourth embodiment

(1) Plasma modification treatment: carrying out low-temperature plasma activation treatment on the sodium super-ion conductor type solid electrolyte particles for 5min under the condition of nitrogen with the gas flow rate of 10m/s, the working current of 1.5A and the voltage of 130V, and then cooling to room temperature to obtain activated sodium super-ion conductor type solid electrolyte particles;

(2) preparing a composite solid electrolyte: weighing PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles obtained in the step (1) according to a proportion of 20 wt.%, dissolving the PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles in acetone and N, N-dimethylformamide, mechanically ball-milling for 24 hours at a rotating speed of 250r/min to obtain a mixed solution, slowly pouring the mixed solution into a polytetrafluoroethylene mold, rolling to a thickness of 40 mu m, and standing in a vacuum drying oven at a temperature of 40 ℃ for 48 hours to remove the organic solvent to obtain the composite solid electrolyte membrane.

This example performed physical and electrochemical testing of the composite solid electrolyte with relatively lower impedance and polarization, and longer cycle life than untreated.

Fifth embodiment

(1) Plasma modification treatment: carrying out low-temperature plasma activation treatment on the sodium super-ion conductor type solid electrolyte particles for 10min under the condition of nitrogen with the gas flow rate of 10m/s, the working current of 1.5A and the voltage of 130V, and then cooling to room temperature to obtain activated sodium super-ion conductor type solid electrolyte particles;

(2) preparing a composite solid electrolyte: weighing PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles obtained in the step (1) according to a proportion of 50 wt.%, dissolving the PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles in acetone and N, N-dimethylformamide, mechanically ball-milling for 10 hours at a rotating speed of 350r/min to obtain a mixed solution, slowly pouring the mixed solution into a polytetrafluoroethylene mold, rolling to a thickness of 50 mu m, and standing in a vacuum drying oven at a temperature of 40 ℃ for 36 hours to remove the organic solvent to obtain the composite solid electrolyte membrane.

This example performed physical and electrochemical testing of the composite solid electrolyte with relatively lower impedance and polarization, and longer cycle life than untreated.

Sixth embodiment

(1) Plasma modification treatment: carrying out low-temperature plasma activation treatment on the sodium super-ion conductor type solid electrolyte particles for 40min under the condition of nitrogen with the gas flow rate of 10m/s, the working current of 0.8A and the voltage of 60V, and then cooling to room temperature to obtain activated sodium super-ion conductor type solid electrolyte particles;

(2) preparing a composite solid electrolyte: weighing PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles obtained in the step (1) according to a proportion of 30 wt.%, dissolving the PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles in acetone and N, N-dimethylformamide, mechanically ball-milling for 30 hours at a rotating speed of 300r/min to obtain a mixed solution, slowly pouring the mixed solution into a polytetrafluoroethylene mold, rolling to a thickness of 60 mu m, and standing in a vacuum drying oven at a temperature of 60 ℃ for 36 hours to remove the organic solvent to obtain the composite solid electrolyte membrane.

This example performed physical and electrochemical testing of the composite solid electrolyte with relatively lower impedance and polarization, and longer cycle life than untreated.

Seventh embodiment

(1) Plasma modification treatment: carrying out low-temperature plasma activation treatment on the sodium super-ion conductor type solid electrolyte particles for 50min under the condition of nitrogen with the gas flow rate of 10m/s, the working current of 1.2A and the voltage of 80V, and then cooling to room temperature to obtain activated sodium super-ion conductor type solid electrolyte particles;

(2) preparing a composite solid electrolyte: weighing PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles obtained in the step (1) according to a proportion of 50 wt.%, dissolving the PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles in acetone and N, N-dimethylformamide, mechanically ball-milling for 30 hours at a rotating speed of 400r/min to obtain a mixed solution, slowly pouring the mixed solution into a polytetrafluoroethylene mold, rolling to a thickness of 60 mu m, and standing in a vacuum drying oven at a temperature of 60 ℃ for 36 hours to remove the organic solvent to obtain the composite solid electrolyte membrane.

This example performed physical and electrochemical testing of the composite solid electrolyte with relatively lower impedance and polarization, and longer cycle life than untreated.

Eighth embodiment

(1) Plasma modification treatment: carrying out low-temperature plasma activation treatment on the sodium super-ion conductor type solid electrolyte particles for 60min under the condition of nitrogen with the gas flow rate of 10m/s, the working current of 0.5A and the voltage of 40V, and then cooling to room temperature to obtain activated sodium super-ion conductor type solid electrolyte particles;

(2) preparing a composite solid electrolyte: weighing PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles obtained in the step (1) according to a proportion of 50 wt.%, dissolving the PVDF-HFP and the activated sodium super-ionic conductor type solid electrolyte particles in acetone and N, N-dimethylformamide, mechanically ball-milling for 30 hours at a rotating speed of 400r/min to obtain a mixed solution, slowly pouring the mixed solution into a polytetrafluoroethylene mold, rolling to a thickness of 60 mu m, and standing in a vacuum drying oven at a temperature of 80 ℃ for 24 hours to remove the organic solvent to obtain the composite solid electrolyte membrane.

This example performed physical and electrochemical testing of the composite solid electrolyte with relatively lower impedance and polarization, and longer cycle life than untreated.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations and simplifications are intended to be included in the scope of the present invention.