Two-dimensional nanochannel ultrafast ion transport technology based on polymer regulation and application thereof in lithium battery
By introducing polymer molecules with lithium ion active transport sites into the nano-limited channel of two-dimensional material in lithium batteries, the problem of low lithium ion transmission rate in traditional lithium batteries is solved, high ion conductivity and excellent low temperature performance are achieved, and the electrochemical performance of lithium batteries is significantly improved.
Patent Information
- Application Number
- CN202510351062.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2025-06-24
AI Technical Summary
The rapid transport of lithium ions in traditional lithium batteries is caused by insufficient ion conductivity. The lithium ions transmission rate in traditional electrolytes is low, and the high activation energy in solid electrolytes limits ion conductivity.
By introducing polymer molecules with lithium ion active transport sites into the nano-limited domain channel of two-dimensional material, precise regulation of angstrom-level layer spacing and ion conductivity is achieved, forming a two-dimensional nanochannel embedded in polymers, regulating the shrinkage and expansion of the nanochannels and improving ionic conductivity.
The ultra-high ionic conductivity of 405.2mS cm-1 is achieved, which is 40 times higher than that of traditional bulk electrolytes, and maintains high ionic conductivity under low temperature conditions, significantly improving the rate performance and cycle stability of lithium batteries.
Smart Images
Figure CN120199819A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of lithium-ion batteries, and particularly to an ultrafast ion transport technology based on polymer regulation in two-dimensional nanochannels and its application in lithium batteries. Background Art
[0002] In lithium batteries, the rapid transport of lithium ions (Li+) is one of the core issues affecting the energy conversion efficiency. However, traditional electrolytes usually have the problem of insufficient ionic conductivity. Taking the commonly used carbonate electrolyte as an example, its lithium ion transport behavior is mainly affected by the solvation structure, that is, the transport process of lithium ions will carry the surrounding solvation shell to move. The steric hindrance effect of this solvation shell and its strong interaction with ions will significantly reduce the transport rate. In addition, the collision between ions and the synchronous transport of anions under an external electric field further reduce the effective lithium ion conductivity (about 10 mS·cm-1). In contrast, the ion transport in solid-state electrolytes (SSEs) depends on the transition of lithium ions through lattice defects in inorganic solid electrolytes or chain segments in polymer solid electrolytes. Although the formation of solvation shells is avoided, the strong electrostatic force between the moving cations and the surrounding anion framework increases the activation energy, limiting the ionic conductivity to generally around 1.0 mS·cm-1.
[0003] Currently, ultrafast ion transport behavior has been achieved by using two-dimensional material nano-confined channels. However, the interlayer size and wall properties of the nanochannels have a significant impact on ion transport. How to regulate and improve the nanochannels to further enhance the lithium ion transport characteristics and increase the ionic conductivity of lithium ions is of great significance for the field of energy storage and energy conversion. Summary of the Invention
[0004] The purpose of the present invention is to provide an ultrafast ion transport technology based on polymer regulation in two-dimensional nanochannels and its application in lithium batteries. To solve the above problems, polymer molecules with lithium ion active transport sites are introduced into the two-dimensional material nano-confined channels, realizing precise regulation of the angstrom-level interlayer spacing and ionic conductivity.
[0005] To achieve the above purpose, the present invention discloses an ultrafast ion transport technology based on polymer regulation in two-dimensional nanochannels. The ion transport channels are modified by using the interaction between polymer molecules and two-dimensional materials to form polymer-embedded two-dimensional nanochannels. By regulating the content of polymer molecules between two-dimensional materials, the contraction and expansion of two-dimensional nanochannels are precisely controlled, and the transport environment of ions in the two-dimensional nanochannels is changed to improve the ionic conductivity; the polymer molecules are water-soluble polymer polymers containing polar groups.
[0006] Preferably, the polymer molecules include synthetic polymers such as sodium polystyrene sulfonate, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, polymaleic acid, and natural polymers such as starches, celluloses, vegetable gums, and animal gums.
[0007] Preferably, the two-dimensional material is a two-dimensional layered material such as graphene, boron nitride, carbon nitride, transition metal sulfide, Mxene, etc.
[0008] Preferably, the two-dimensional nanochannel is a two-dimensional laminar membrane structure, and the preparation of the two-dimensional nanochannel includes the following steps:
[0009] (1) Dissolve the polymer molecules in a two-dimensional material dispersion with a concentration range of 1-10 mg / ml to form a homogeneous mixed solution of dispersed polymer and two-dimensional nanomaterials with the two-dimensional material solution and the polymer molecules.
[0010] (2) Prepare a composite material film with an ordered stacked layered structure by vacuum filtration of the mixed solution.
[0011] (3) Place the composite material film in an oven for heating, peel it off from the filter membrane substrate, and cut it into rectangular samples of the two-dimensional laminar membrane to obtain the two-dimensional nanochannel material.
[0012] Preferably, in step (2), the negative pressure of vacuum filtration is ~0.9 bar, and in step (3), the temperature of the oven is 80 °C and the heating time is 24 h.
[0013] The present invention also provides the application of the above polymer-regulated two-dimensional nanochannel ultrafast ion transport technology in lithium-ion batteries, and a two-dimensional nanochannel lithium ion transport network is constructed in the positive electrode of the lithium-ion battery by using the two-dimensional nanochannel.
[0014] Preferably, the preparation and assembly of the positive electrode and the full battery of the lithium-ion battery include the following steps:
[0015] S1. Mix and stir the positive electrode powder, SuperP carbon black, and PVDF binder in a mass ratio of 8:1:1 in N-methyl-2-pyrrolidone containing the two-dimensional nanochannel material to obtain a slurry, wherein the dissolved mass fraction of the PVDF binder in N-methyl-2-pyrrolidone is 40 mg / ml.
[0016] S2. Coat the slurry on the surface of the aluminum foil, dry it at 80 °C, and cut it into circular pieces to obtain the positive electrode current collector, and the positive electrode current collector serves as the electrode sheet of the positive electrode of the lithium-ion battery.
[0017] S3. In a glove box filled with argon gas, CR2025 coin cells were assembled using the prepared electrode as the working electrode and lithium metal as the counter electrode. The addition amount of the lithium salt electrolyte in each cell was 30 - 60 μL, and all coin cells were cycled in a constant current mode within a voltage range of 2.3 - 3.9 V.
[0018] Preferably, in step S1, the positive electrode powder is any one of lithium iron phosphate powder, ternary nickel cobalt manganese oxide powder, or lithium-rich oxide powder. The positive electrode powder, SuperP carbon black, and PVDF binder are mixed at a mass ratio of 8:1:1. The mass-volume ratio of the two-dimensional nanochannel to N-methyl-2-pyrrolidone is 1 - 8 mg / ml, and the addition amount of the two-dimensional nanochannel is 0.25 - 2 wt% of the slurry mass.
[0019] Preferably, the lithium salt electrolyte is any one of carbonate electrolytes containing lithium hexafluorophosphate and ether electrolytes containing lithium bis(trifluoromethanesulfonyl)imide.
[0020] Preferably, in step S2, the scraping thickness of the slurry is 40 μm, and the size of the circular sheet is about 1.12 cm. 2 。
[0021] Therefore, the present invention has the following beneficial effects:
[0022] (1) The structural main body of graphene oxide is a graphene substrate with an unoxidized conjugated aromatic ring structure and a large number of oxygen-containing functional groups generated by oxidation, such as epoxy groups, hydroxyl groups, and carboxyl groups. PSS is a hydrophilic and electrically insulating polymer whose chemical structure is based on polystyrene and contains benzene rings, sulfonic acid (SO3 - ) and sodium (Na + ) ions. The long alkane chain and benzene ring at the hydrophobic end can form strong non-covalent interactions with the conjugated aromatic ring structure on the GO nanosheet; sodium ions can be partially dissociated from the sulfonic acid groups covalently bound to the benzene ring in the electrolyte and generate electrostatic interactions with the negatively charged GO surface; the twisted molecular backbone and sulfonic acid groups of PSS can provide fast hopping sites for lithium ion (Li + ) transport, which can improve the transport efficiency of Li + . By introducing polymer molecules with lithium ion active transport sites into the two-dimensional material nano-confined channels, the present invention realizes the precise regulation of angstrom-level layer spacing and ionic conductivity, achieving an ultra-high ionic conductivity of 405.2 mS cm -1 , which is 2.5 times that of the initial membrane (160.7 mS cm -1 ) and 40 times higher than that of the traditional bulk electrolyte (10.3 mS cm -1 ), demonstrating the role of two-dimensional confinement effect and the introduction of PSS in enhancing ionic conductivity.
[0023] (2) In the nano-confined channels, the low-temperature performance of ion transport is greatly improved. At -50 °C, the effective ionic conductivity of the electrolyte remains at about 2 mS·cm-1, which is two orders of magnitude higher than the corresponding bulk ionic conductivity (the bulk conductivity is only 0.07 mS·cm-1).
[0024] (3) Based on two-dimensional nano-channels, an efficient lithium-ion transport network is constructed in the positive electrode of lithium-ion batteries, significantly improving the rate performance and cycle stability of lithium batteries.
[0025] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings
[0026] Figure 1 Schematic diagram for the preparation of polymer-embedded two-dimensional nano-channels in Example 1;
[0027] Figure 2 Characterization diagram of the GO@PSS two-dimensional nano-channels prepared in Example 1. a is the cross-sectional SEM characterization diagram of the pure GO film, b is the cross-sectional SEM characterization diagram of the GO@PSS two-dimensional nano-channels, c is the cross-sectional SEM morphology and EDS element characterization diagram of GO@PSS, d is the XPS spectrum of the GO@PSS film, and e is the S2p characteristic spectrum;
[0028] Figure 3 Diagram showing the influence of different PSS contents on the performance of the GO@PSS two-dimensional nano-channels in Example 1. a is the ionic conductivity of the GO@PSS films with different PSS contents, b is the change in the layer spacing of the GO@PSS films with the PSS content, and c is a schematic diagram of the GO interlayer containing no PSS, a small amount of PSS, and a large amount of PSS molecules;
[0029] Figure 4 Variation of the ionic conductivity of the LiPF6-EC / DMC electrolyte with temperature in the bulk and nano-confined systems. The inset is a photo of the electrolyte before and after solidification;
[0030] Figure 5 Diagram of the freezing point test of the LiPF6-EC / DMC electrolyte using a low-temperature chamber;
[0031] Figure 6 Schematic diagram of the rapid lithium-ion transport channels in the GO-based lithium iron phosphate (LFP) positive electrode;
[0032] Figure 7 Comparison diagram of the rate performance of LFP||Li batteries, multi-layer GO@LFP||Li batteries, and single-layer GO@LFP||Li batteries;
[0033] Figure 8 Rate performance graphs of GO@LFP||Li battery and LFP||Li battery;
[0034] Figure 9 Long cycle performance graphs of GO@LFP||Li battery and LFP||Li battery. Detailed implementation manners
[0035] The technical solutions of the present invention will be further described below through examples.
[0036] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs.
[0037] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. The narrative manner of this specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. These other embodiments are also covered by the protection scope of the present invention.
[0038] Example 1
[0039] This example provides a polymer-embedded two-dimensional nanochannel, and its preparation process is as Figure 1 shown. The specific experimental steps are as follows: Dissolve soluble PSS polymer molecules into 3 ml of GO aqueous dispersion with a concentration of 2 mg / ml at ratios of 0.3%, 0.7%, 1.5%, 3%, 5%, 8%, and 10% respectively to obtain a uniformly dispersed composite aqueous dispersion of PSS and GO. Prepare a GO@PSS film with an ordered stacked layered structure by vacuum filtration (~0.9 bar) of the obtained composite solution. Place the filtered film in an oven and heat it at 80 °C for 12 hours. Then peel the composite material film from the filter membrane substrate, and then cut it into rectangular samples and encapsulate them in PDMS polymer to fabricate a device.
[0040] To verify the successful intercalation of PSS into GO in the GO@PSS two-dimensional nanochannel with a PSS content of 1.5 wt% prepared in Example 1, the characteristics of the GO@PSS film were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) respectively. It was found by cross-sectional scanning electron microscopy (SEM) characterization that the film surface became rougher after PSS modification treatment compared with the pure GO film ( Figure 2 a in and b in 2). The obtained GO@PSS film has a parallel and regular layered structure ( Figure 2In c), this is a prerequisite for realizing uniform and practical ion-transporting nanochannels. At the same time, the EDS spectrum results show that the presence of sulfur and sodium elements is verified in the GO@PSS composite film. XPS further provides conclusive evidence for the intercalation of PSS and its interaction with GO sheets. Figure 2 The XPS full-spectrum scanning results in d) show that characteristic peaks of S2p of sulfur and Na 1s (1073.2 eV) of sodium exist in the GO@PSS thin film, while these peaks are completely absent in the GO thin film. In addition, the XPS analysis of S2p ( Figure 2 in e) shows two fitting peaks, respectively representing the oxidized sulfur (168.2 eV and 169.2 eV) connected to the benzene ring, and these peaks come from the From the analysis results of SEM and XPS, it can be confirmed that the PSS polymer has been successfully intercalated into the GO thin film.
[0041] The ion conductivity of the above-prepared GO@PSS two-dimensional nanochannel was detected. Electrochemical impedance spectroscopy (EIS) was tested using an electrochemical workstation, and the calculated ion conductivity values were summarized in Figure 3 in a). During the test, it is necessary to ensure the tight connection between the electrodes and both ends of the GO@PSS two-dimensional nanochannel film. When the workstation operates stably, record the open-circuit voltage scanned at the lower left corner of the software. Enter the page of electrochemical impedance parameters, fill in the open-circuit voltage value, set the highest frequency to 100 KHz, and the lowest frequency to 1 Hz. The amplitude and standing time adopt the default values, click OK, and conduct the electrochemical impedance test. Try to ensure the continuity of the scanned data.
[0042] The resistance value between the electrode and the electrolyte cross-section was obtained by fitting with Zview software. The sample length and cross-sectional area were calculated from the size of the graphene oxide assembly film in the size test. The ion conductivity calculation formula for the ion transport membrane is:
[0043]
[0044] The ion transport ability of the GO@PSS two-dimensional nanochannel prepared in Example 1 above was detected. Lithium hexafluorophosphate (LiPF6)-ethylene carbonate / dimethyl carbonate (EC / DMC, 1:1 volume ratio) electrolyte commonly used in the field of lithium batteries was selected to measure the ionic conductivity, and its concentration was 1 mol / L. The prepared GO@PSS film was cut into rectangular strips, and the dimensions of the film were measured: the length and width of the GO@PSS film were measured and recorded using a vernier caliper; the thickness of the GO@PSS film was measured and recorded using a SEM cross-sectional view. Then the GO@PSS rectangular strip was encapsulated into a polydimethylsiloxane (PDMS) mold. After curing at 60 °C, electrolyte reservoirs with a capacity of 0.1 mL were prepared at both ends of the ion transport membrane. The electrolyte was added dropwise and allowed to stand for 24 hours until the electrolyte fully infiltrated the two-dimensional nanochannel.
[0045] The ionic conductivities of GO@PSS two-dimensional nanochannels with different PSS contents measured by an electrochemical workstation were totaled to Figure 3 a in. The results show that as the PSS content in the GO interlayer gradually increases, the ionic conductivity of the confined LiPF6-EC / DMC electrolyte shows a trend of first increasing and then decreasing. In the pure GO film without PSS, the ionic conductivity of the electrolyte in the two-dimensional confinement system is 160.7 mS cm -1 , which is an order of magnitude higher than that of the bulk electrolyte (10.3 mS cm -1 ); when the PSS increases to 1.5%, the ionic conductivity reaches the highest, about 405.2 mS cm -1 ; as the PSS content continues to increase, the ionic conductivity decreases instead. When the PSS content increases to 10%, the ionic conductivity drops to 56.3 mS cm -1 . These results indicate that the ionic conductivity of the two-dimensional confined electrolyte has been significantly improved, and the introduction of PSS plays a crucial role in regulating the ionic conductivity. To explain the reason for the change in ionic conductivity, the layer spacing of composite membranes with different PSS contents was characterized, and it was found that the layer spacing shows a trend of first decreasing and then increasing with the increase of PSS content ( Figure 3 b in). It shows that when the PSS content is low, the strong non-covalent interaction between the alkane chains and benzene rings of PSS molecules and the conjugated aromatic ring structure of GO and the electrostatic adsorption between Na + and GO dominate, resulting in the contraction of the nanochannel and the reduction of the layer spacing. At this time, the appropriate amount of PSS sulfonic acid groups provides many rapid jump sites for Li + , thus improving the transport efficiency. Then, as PSS is in excess, a large number of entangled PSS molecules fill the interlayer, breaking the interlayer attraction and expanding the layer spacing. The random entanglement of PSS molecular chains also increases the ion transport resistance, resulting in a decrease in ionic conductivity instead (Figure 3 in c).
[0046] Compared with the bulk electrolyte, the abnormal behavior of the electrolyte in the nano-confined system with the channel characteristic size limited to the nano / sub-nano scale not only includes the ultra-high-speed ion transport state, but also indicates that new phase transition behaviors may occur due to the change of particle-particle interactions. The two-dimensional GO nanochannels with a regular layered arrangement provide a convenient platform for studying the special physical phenomena in the nanochannels. To reveal the influence of the nano-confined space on the phase transition behavior, the temperature-dependent ionic conductivity test of the GO@PSS two-dimensional nanochannels was carried out.
[0047] As Figure 4 shown, the temperature-dependent electrochemical impedance spectroscopy (EIS) was used to compare the ionic conductivity change behaviors of the LiPF6 / EC+DMC electrolyte in the nano-confined system and the bulk phase. The results show that in the bulk electrolyte (concentration: 1 mol / L), the ionic conductivity curve drops sharply between -35 °C and -40 °C, and the drop amplitude is close to one order of magnitude. This phenomenon is attributed to the formation of a rigid ice lattice by the liquid electrolyte when approaching the freezing point, which restricts the ion transport. However, in the two-dimensional nanochannels of GO@PSS, the rapid decrease of the ionic conductivity of the LiPF6 / EC+DMC electrolyte only appears at -60 °C. At -50 °C, the effective ionic conductivity of the electrolyte in the nano-confined system still remains at about 2 mS·cm-1, which is two orders of magnitude higher than the bulk ionic conductivity at the corresponding temperature (the bulk conductivity is only 0.07 mS·cm-1).
[0048] To clarify the reason for the discontinuous change of the ionic conductivity, the phase transition freezing point test of the LiPF6-EC / DMC electrolyte was carried out using the same test device ( Figure 5 ). The results show that the phase transition temperatures of the bulk LiPF6-EC / DMC electrolyte are about -35 °C respectively, and these temperatures are consistent with the sharp change temperatures observed in the ionic conductivity-temperature relationship. Therefore, through reasonable speculation, it can be known that the sharp change of the ionic conductivity in the nano-confined electrolyte is also related to the phase transition of the electrolyte, that is, the temperature of the discontinuous change of the ionic conductivity is consistent with the phase transition temperature of the nano-confined electrolyte. According to this inference, it can be found that the phase transition temperature in the nano-confined state is lower than that in the bulk state, indicating that the ionic transport behavior under nano-confinement has significant advantages in low-temperature applications.
[0049] Therefore, the GO@PSS composite laminar film intercalated with graphene oxide (GO) and poly(sodium 4-styrenesulfonate) (PSS) prepared in Example 1 can precisely control the contraction and expansion of two-dimensional nanochannels and change the ion transport environment in the channels by introducing different contents of PSS polymers between the GO layers through the suction filtration method, thereby effectively improving the ionic conductivity.
[0050] The GO@PSS two-dimensional nanochannel with a PSS content of 1.5 wt% prepared in Example 1 was applied to a lithium-ion battery. The commercial lithium iron phosphate (LFP) cathode was selected as the research object. Based on the lithium-ion nanochannel network of the graphene oxide film, a lithium battery cathode design was proposed. The schematic diagram of the fast lithium-ion transport channel in this cathode is as Figure 6 shown. The LFP cathode was prepared by mixing LFP powder, Super P carbon black, and PVDF binder in a mass ratio of 8:1:1 and stirring in N-methyl-2-pyrrolidone (NMP). The GO@LFP cathode was prepared using the same mass ratio, except that the multi-layer GO nanosheets were first dissolved in NMP at a ratio of 2 mg / ml and stirred to obtain a uniformly dispersed slurry (the GO content was 0.5 wt% of the overall cathode material). Subsequently, the LFP slurry and the GO@LFP slurry were respectively coated on the surface of the aluminum foil and cut into circular pieces (about 1.12 cm 2 ) as the positive electrode current collector after drying at 80°C. Electrochemical studies were carried out using 2032-type coin cells (MTI Corporation), and the battery assembly was carried out in a glove box filled with Ar (H2O < 0.1 ppm, O2 < 0.1 ppm). The full battery assembly used 40 μL of electrolyte (1 M LiPF6, DEC:DMC:EC = 1:1:1 Vol%, containing 1% VC), polyethylene (PE) as the separator, and lithium foil (200 μm) as the negative electrode.
[0051] To verify that the optimized ion transport path in the cathode depends on the nanochannels between the multi-layer nanosheets, and single-layer nanosheets cannot construct interlayer nanochannels, single-layer GO nanosheets and multi-layer GO nanosheets were selected and added to the battery cathode for performance comparison. The rate performance comparisons of the LFP||Li battery, the multi-layer GO-PSS@LFP||Li battery, and the single-layer GO@LFP||Li battery are as Figure 7As shown, the results show that the battery containing single-layer GO nanosheets has no performance improvement and is significantly lower than the battery with an interlayer nanochannel structure composed of a multi-layer GO structure. Therefore, the main mechanism for improving the rate performance is the lithium-ion transport kinetics accelerated by the GO interlayer nanochannel network, rather than the inherent properties of the GO nanosheets themselves. The interlayer ion transport channels between GO nanosheets are the main determining factor for improving the rate performance of the battery.
[0052] In the assembled full battery, a LiPF6-based carbonate electrolyte was used to evaluate the rate performance of the GO-PSS@LFP||Li battery and compared with the control LFP||Li battery. When using a high areal loading of the LFP cathode, the GO-PSS@LFP||Li battery demonstrated excellent rate performance ( Figure 8 ). Compared with the severe capacity decay of the LFP||Li battery, the GO-PSS@LFP||Li battery could still provide a capacity of 120 mAh g -1 at 3C, demonstrating a breakthrough in achieving fast lithium-ion transport kinetics based on the GO-based ion transport network at high current densities. At 0.5C, the GO-PSS@LFP||Li battery recovered to a capacity of 160 mAh g -1 , indicating that no structural damage occurred to the LFP cathode. After the rate test, the GO-PSS@LFP||Li battery exhibited stable long-cycle performance at a 1C rate ( Figure 9 ). Compared with the rapid capacity decay of the LFP||Li battery, the capacity retention rate of the GO@LFP||Li battery was 80% after 460 cycles at a 1C rate. The above results highlight the feasibility of the nano-confined interlayer structure in promoting fast ion transport and demonstrate the great potential of the GO nanochannels in enhancing the electrochemical performance of the battery.
[0053] Therefore, the present invention provides a two-dimensional nanochannel ultrafast ion transport technology based on polymer regulation and its application in lithium batteries. By introducing polymer molecules with lithium-ion active transport sites into the nano-confined channels of two-dimensional materials, precise regulation of the angstrom-level interlayer spacing and ionic conductivity is achieved.
[0054] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.
Claims
1. Ultrafast ion transport technology based on polymer-regulated two-dimensional nanochannels, characterized in that: The interaction between polymer molecules and two-dimensional materials is used to modify the ion transport channel to form a polymer-embedded two-dimensional nanochannel. By regulating the content of polymer molecules between the two-dimensional materials, the contraction and expansion of the two-dimensional nanochannel are precisely controlled, and the transmission environment of ions in the two-dimensional nanochannel is changed to improve the ion conductivity; the polymer molecules are water-soluble high molecular polymers containing polar groups.
2. The two-dimensional nanochannel ultrafast ion transport technology based on polymer regulation according to claim 1, characterized in that: The polymer molecules include synthetic polymers and natural polymers. The synthetic polymer is any one of sodium polystyrene sulfonate, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, and polymaleic acid. The natural polymer is any one of starch, cellulose, plant glue, and animal glue.
3. The two-dimensional nanochannel ultrafast ion transport technology based on polymer regulation according to claim 1, characterized in that: The two-dimensional material is any two-dimensional layered material of graphene, boron nitride, carbon nitride, transition metal sulfide, and Mxene.
4. The two-dimensional nanochannel ultrafast ion transport technology based on polymer regulation according to claim 1, characterized in that: The two-dimensional nanochannel is a two-dimensional laminar membrane structure, and the preparation of the two-dimensional nanochannel comprises the following steps: (1) dissolving polymer molecules in a two-dimensional material dispersion having a concentration of 1-10 mg / ml to form a mixed solution of uniformly dispersed polymers and two-dimensional nanomaterials; (2) preparing the mixed solution into a composite film having an ordered stacked layer structure by vacuum filtration; (3) The composite film is placed in an oven for heating, peeled off from the filter membrane substrate, and cut into two-dimensional laminar membrane rectangular samples to obtain a two-dimensional nanochannel material.
5. The two-dimensional nanochannel ultrafast ion transport technology based on polymer regulation according to claim 4, characterized in that: In step (2), the negative pressure of the vacuum filtration is 0.9 bar, and in step (3), the temperature of the oven is 80° C. and the heating time is 24 h.
6. An application of the polymer-regulated two-dimensional nanochannel ultrafast ion transport technology as claimed in any one of claims 1 to 5, characterized in that: The polymer-regulated two-dimensional nanochannel ultrafast ion transport technology is applied to lithium-ion batteries, and a two-dimensional nanochannel lithium-ion transport network is constructed in the positive electrode of the lithium-ion battery using the two-dimensional nanochannel.
7. The application of the polymer-regulated two-dimensional nanochannel ultrafast ion transport technology according to claim 6, characterized in that: The preparation and assembly of lithium-ion battery positive electrode and full battery includes the following steps: S1. The positive electrode powder, SuperP carbon black and PVDF binder are mixed and stirred in N-methyl-2-pyrrolidone containing two-dimensional nanochannel material in a mass ratio of 8:1:1 to obtain a slurry, wherein the dissolved mass fraction of the PVDF binder in N-methyl-2-pyrrolidone is 40 mg / ml; S2, applying the slurry on the surface of aluminum foil, drying at 80° C. and cutting into circular sheets to obtain a positive electrode current collector, which is used as a positive electrode sheet of a lithium-ion battery; S3. In a glove box filled with argon, CR2025 button cells were assembled using the electrode prepared in S2 as the working electrode and lithium metal as the counter electrode. The amount of lithium salt electrolyte added to each button cell was 30-60 μL, and all the button cells were cycled in a constant current mode within a voltage range of 2.3-3.9 V.
8. The application of the polymer-regulated two-dimensional nanochannel ultrafast ion transport technology according to claim 7, characterized in that: In step S1, the positive electrode powder is any one of lithium iron phosphate powder, ternary nickel cobalt manganese oxide powder or lithium-rich oxide powder, the positive electrode powder, SuperP carbon black and PVDF binder are mixed in a mass ratio of 8:1:1, the mass volume ratio of the two-dimensional nanochannel material to N-methyl-2-pyrrolidone is 1-8 mg / ml, and the amount of the two-dimensional nanochannel material added is 0.25-2wt% of the slurry mass.
9. The application of the polymer-regulated two-dimensional nanochannel ultrafast ion transport technology according to claim 7, characterized in that: The lithium salt electrolyte is any one of a carbonate electrolyte containing lithium hexafluorophosphate and an ether electrolyte containing lithium bis(trifluoromethylsulfonyl)imide.
10. The application of the polymer-regulated two-dimensional nanochannel ultrafast ion transport technology according to claim 7, characterized in that: In step S2, the coating thickness of the slurry is 40 μm.