Zwitterionic cellulose-based solid electrolyte membrane, method of preparation and use thereof

Abstract

The application relates to the field of battery material preparation, and discloses a zwitterionic cellulose-based solid electrolyte membrane, a preparation method and application thereof, the preparation method comprises the following steps: S1: mixing ZCNF and copper sulfate in an aqueous solution to form a mixture, then adding a lithium salt into the mixture to react, so as to obtain a ZCNF-CuSO4-containing precursor; wherein the ZCNF is a zwitterionic cellulose nanofiber; S2: after the ZCNF-CuSO4-containing precursor is dried, ion exchange reaction is carried out with a lithium salt electrolyte, so as to obtain a Li-ZCNF-CuSO4-containing cellulose-based material. The zwitterionic cellulose-based solid electrolyte membrane has high ionic conductivity and lithium ion transference number in a normal temperature environment of 30-70 DEG C, and the application of a solid-state lithium metal battery in a normal temperature scene is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of battery material preparation, in particular to a zwitterionic cellulose-based solid-state electrolyte membrane, a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of new energy technology, the market puts forward higher requirements for the performance of solid-state lithium metal batteries. As a key component of solid-state lithium metal batteries, solid-state electrolyte plays a key role in isolating the positive and negative electrodes, preventing short circuits, and ensuring efficient conduction of lithium ions. Its performance directly affects the core parameters of solid-state lithium metal batteries, such as power density, cycle stability, and high and low temperature performance.

[0003] Polyethylene oxide (PEO) has good film-forming properties and high compatibility with lithium salts, and is a commonly used polymer solid-state electrolyte component. However, the ionic conductivity of PEO-based solid-state electrolyte is highly dependent on temperature, and the ionic conductivity is low at room temperature around 40℃, which cannot meet the battery dynamics requirements, greatly limiting the application of solid-state lithium metal batteries in room temperature scenarios. SUMMARY

[0004] To solve the above technical problems, the present application provides a zwitterionic cellulose-based solid-state electrolyte membrane, which has high ionic conductivity and lithium ion transference number at an environment of 30-70℃, realizing the application of solid-state lithium metal batteries in room temperature scenarios.

[0005] The specific technical scheme of the present application is as follows: a preparation method of a zwitterionic cellulose-based solid-state electrolyte membrane, comprising the following steps:

[0006] S1: mixing ZCNF and copper sulfate in an aqueous solution to form a mixture, then adding lithium salt to the mixture to react, obtaining a precursor containing ZCNF-CuSO4; wherein ZCNF is zwitterionic cellulose nanofiber;

[0007] S2: drying the precursor containing ZCNF-CuSO4, and performing ion exchange reaction with lithium salt electrolyte to obtain a cellulose-based material containing Li-ZCNF-CuSO4.

[0008] The above zwitterionic cellulose-based solid-state electrolyte membrane uses ZCNF with good room temperature stability as a base material. ZCNF and copper sulfate are mixed in an aqueous solution. The dissociation of copper sulfate in water is and , which improves the ionic strength of the solution. ZCNF unfolds its molecular chain in the salt solution due to the anti-polyelectrolyte effect, and the fibers are dispersed from each other, thereby widening the molecular channels between the cellulose chains, effectively overcoming the problem of narrow spacing between cellulose molecules due to hydrogen bonding, making Li +The zwitterionic cellulose nanofiber can be easily inserted into the cellulose chain and transferred, thereby improving the ionic conductivity of the electrolyte membrane and the lithium ion transference number. The electrolyte membrane introduces lithium ions as a dynamic transmission medium while enhancing the interface stability, improving the transmission efficiency of lithium ions at the interface, and realizing the application of the solid-state lithium metal battery in a normal temperature field.

[0009] Optionally, the ZCNF contains quaternary ammonium salt cation groups and carboxylate anion groups.

[0010] The cationic functional groups on the ZCNF, -(CH3)3N + , can effectively anchor the anions in the lithium salt, promote the dissociation of the lithium salt, and avoid the adverse effects of concentration polarization caused by the accumulation of anions. The anionic functional groups, -COO - , can provide additional Lewis basic sites to attract Li + , thereby providing an additional channel for lithium ion transmission and further improving the ionic conductivity of the electrolyte membrane and the lithium ion transference number.

[0011] Optionally, in step S1, the ZCNF is 20-30 parts by weight, and the copper sulfate is 40-50 parts by weight.

[0012] Optionally, in step S1, the lithium salt is dissolved in polyethylene glycol dimethyl ether to form a supersaturated solution of the lithium salt, and then the mixture is added for reaction, wherein the lithium salt includes lithium bis(trifluoromethanesulfonyl)imide.

[0013] Optionally, in step S1, the weight ratio of the zwitterionic cellulose nanofiber ZCNF to the lithium salt is 1:1-2.

[0014] Optionally, in step S2, the precursor containing ZCNF-CuSO4 is soaked in a lithium salt electrolyte, and the lithium salt concentration in the lithium salt electrolyte is 0.8-1.2 mol / L, and the soaking time is 48-96 h.

[0015] Optionally, in the lithium salt electrolyte, the lithium salt includes lithium bis(trifluoromethanesulfonyl)imide, and the solvent includes a mixed solution formed by mixing 1,3-dioxolane and dimethoxyethane.

[0016] Optionally, the following steps are further included:

[0017] S3: drying the cellulose-based material containing Li-ZCNF-CuSO4 to obtain a zwitterionic cellulose-based solid electrolyte membrane.

[0018] The second specific technical solution of the present application is a zwitterionic cellulose-based solid electrolyte membrane prepared by the above method.

[0019] The third specific technical solution of the application is: application of the zwitterionic cellulose-based solid-state electrolyte membrane prepared by the above method in a solid-state lithium metal battery.

[0020] Compared with the prior art, the application has at least the following advantages:

[0021] (1) ZCNF with good room temperature stability is used as a base material, and the anti-polyelectrolyte effect of ZCNF can disperse the fibers from each other under the action of CuSO4, thereby widening the molecular channels between cellulose chains, effectively overcoming the problem of narrow spacing between cellulose molecules caused by hydrogen bonding, so that Li + can be more easily inserted into the cellulose chain and transferred, and the ionic conductivity at room temperature reaches 1.01*10 –4 S cm –1 , which is much higher than that of PEO solid-state electrolyte;

[0022] (2) The cationic functional groups (-(CH3)3N + ) on ZCNF can effectively anchor the anions in the lithium salt, promote the dissociation of the lithium salt, and avoid the adverse effects of concentration polarization caused by the accumulation of anions. The anionic functional groups (-COO - ) can provide additional Lewis basic sites to attract Li + , providing an additional channel for lithium ion transport, so that the lithium ion transference number of the zwitterionic cellulose-based solid-state electrolyte membrane at room temperature reaches 0.36;

[0023] (3) The zwitterionic cellulose-based solid-state electrolyte membrane exhibits excellent interface stability, and the critical current density of the Li|Li-ZCNF-CuSO4|Li symmetric battery reaches 0.6 mA cm -2 , and can be stably charged and discharged for nearly 1500 h at a current density of 0.2 mA cm -2 , and the overpotential always remains below 0.1 V;

[0024] (4) The zwitterionic cellulose-based solid-state electrolyte membrane is assembled with LiFePO4 cathode material to assemble a lithium metal battery, which exhibits good rate performance at room temperature, even at a high rate of 5C, still maintains a capacity of nearly 84.05 mAh g -1 , and can be stably cycled for nearly 700 cycles at a current density of 0.5C without obvious capacity decay. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of the conduction mechanism of the zwitterionic cellulose-based solid-state electrolyte membrane of the application;

[0026] Figure 2 This is a morphological diagram of the zwitterionic cellulose-based solid electrolyte membrane of the present invention;

[0027] Figure 3 These are the XRD spectra of ZCNF, ZCNF-CuSO4, and Li-ZCNF-CuSO4;

[0028] Figure 4 This is a Nyquist plot of the zwitterionic cellulose-based solid electrolyte membrane of the present invention at 30-70°C;

[0029] Figure 5 This is the Nyquist plot of PEO solid electrolyte at 30-70℃;

[0030] Figure 6 This is the Arrhenius diagram of the zwitterionic cellulose-based solid electrolyte membrane of the present invention;

[0031] Figure 7 This is a graph showing the lithium-ion migration rate of the zwitterionic cellulose-based solid electrolyte membrane of the present invention at 25°C.

[0032] Figure 8 This is a graph showing the lithium-ion migration rate of PEO solid electrolyte at 25°C.

[0033] Figure 9 It is a Li|Li-ZCNF-CuSO4|Li symmetric cell at 0.2 mAcm -2 Impedance changes during the first 80 cycles;

[0034] Figure 10 This is the Nyquist plot of the initial state Li|Li-ZCNF-CuSO4|Li symmetric cell;

[0035] Figure 11 It is a graph showing the relationship between frequency and phase angle;

[0036] Figure 12 This is the Nyquist plot of the Li|Li-ZCNF-CuSO4|Li symmetric cell at 25℃;

[0037] Figure 13 This is the Nyquist plot of a Li|PEO|Li symmetric cell at 25℃;

[0038] Figure 14 This is a diagram showing the critical current density of a Li|Li-ZCNF-CuSO4|Li symmetric cell at 25℃.

[0039] Figure 15 The Li|Li-ZCNF-CuSO4|Li symmetric cells and Li|PEO|Li symmetric cells have a current of 0.2 mA / cm² at 25°C. –2-0.2 mAh cm –2 the long cycle performance graph of LFP|Li-ZCNF-CuSO4|Li full battery;

[0040] Figure 16 is the rate cycle performance test graph of LFP|Li-ZCNF-CuSO4|Li full battery;

[0041] Figure 17 is the specific capacity-voltage graph of LFP|Li-ZCNF-CuSO4|Li full battery;

[0042] Figure 18 is the 0.5C cycle performance test graph of LFP|Li-ZCNF-CuSO4|Li full battery;

[0043] In the figure: In the Nyquist graph, Z' is the real part impedance, -Z'' is the imaginary part impedance; In the Arrhenius graph, σ is the conductivity. DETAILED DESCRIPTION

[0044] The present application will be described in detail below through specific examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application, and any changes and advantages that can be thought of by those skilled in the art without departing from the spirit and scope of the present application are included in the present application, and the appended claims and any equivalents thereof are the protection scope of the present application.

[0045] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The raw materials, equipment used in the present application are conventional raw materials, equipment in the art, which can be obtained from conventional commercial channels, unless otherwise specified; The method used in the present application is a conventional method in the art, unless otherwise specified.

[0046] The main materials and reagents used in the following examples are described, please see Table 1 for details:

[0047] Table 1 Main experimental drugs and reagents

[0048]

[0049] Example 1: The present application provides a preparation method of a zwitterionic cellulose-based solid-state electrolyte membrane, comprising the following steps:

[0050] (1) Take 20 g of 1.2 wt.% mass fraction ZCNF aqueous solution, then add 2 mL of copper sulfate solution (containing 0.45 g of copper sulfate) under stirring, and make the solution into a uniform paste by continuous stirring and dispersing, then add 1 mL of LiTFSI PEG-DME 250The supersaturated solution (containing 0.24 g of LiTFSI) acts as a fiber binder and lithium ion conducting medium, after 6 h of uniform stirring, two drops of glycerol are added as a plasticizer to ensure the flexibility of the fiber after film formation, obtaining a paste-like ZCNF-CuSO4-containing precursor;

[0051] (2) The paste-like ZCNF-CuSO4-containing precursor is poured into a polytetrafluoroethylene mold, placed in a 40°C air oven for 12 h to dry into a film, then taken out, cut into 19 mm round pieces with a film cutter, and then washed with dimethylformamide (DMF) solvent to replace the residual water in the fiber membrane, and finally evaporated in an oven to remove DMF, obtaining a solid precursor;

[0052] (3) The solid precursor is soaked in 1 mol / L LiTFSI in DOL / DME = 1:1 lithium salt electrolyte for 48 h, ion exchange is carried out to insert Li + into ZCNF-CuSO4, obtaining a Li-ZCNF-CuSO4-containing cellulose-based material;

[0053] (4) The Li-ZCNF-CuSO4-containing cellulose-based material is placed in a glove box to dry and evaporate the solvent, obtaining a zwitterionic cellulose-based solid electrolyte membrane.

[0054] The conduction mechanism of the zwitterionic cellulose-based solid electrolyte membrane prepared by the above method is shown in Figure 1 ZCNF is dispersed from each other under the action of CuSO4 due to the anti-polyelectrolyte effect, thereby widening the molecular channels between cellulose chains, and Li + can be better inserted and transferred. In addition, the oxygen-containing polar functional groups (-OH, -COO - ) present in ZCNF can dissolve Li + and help the transfer of Li + .

[0055] As shown in Figure 3 , the initial state of ZCNF has typical cellulose diffraction peaks (corresponding to (110) and (200) crystal faces, respectively) showing crystallinity, which proves that the original ZCNF is arranged in a tight fiber packing, in contrast, the cellulose diffraction peaks in ZCNF-CuSO4 disappear, showing an amorphous state. The amorphous structure of cellulose has much lower packing density, and the molecular channels between cellulose chains are open. After Li + is inserted into these channels, the final Li-ZCNF-CuSO4 structure still remains amorphous, proving that it is suitable for Li + transfer, verifying the above mechanism.

[0056] As shown in Figure 2Figure 1 shows the optical photograph of the zwitterionic cellulose-based solid-state electrolyte film in (a) flat state, Figure 2 Figure 1 shows the optical photograph of the zwitterionic cellulose-based solid-state electrolyte film in (a) flat state, Figure 2 Figure 1 shows the optical photograph of the zwitterionic cellulose-based solid-state electrolyte film in (a) flat state, Figure 2 Figure 1 shows the optical photograph of the zwitterionic cellulose-based solid-state electrolyte film in (a) flat state, Figure 2 Figure 1 shows the optical photograph of the zwitterionic cellulose-based solid-state electrolyte film in (a) flat state, Figure 2 Figure 1 shows the optical photograph of the zwitterionic cellulose-based solid-state electrolyte film in (a) flat state, Figure 2 Figure 1 shows the optical photograph of the zwitterionic cellulose-based solid-state electrolyte film in (a) flat state, Figure 2 Figure 1 shows the optical photograph of the zwitterionic cellulose-based solid-state electrolyte film in (a) flat state, Figure 2 Figure 1 shows the optical photograph of the zwitterionic cellulose-based solid-state electrolyte film in (a) flat state,

[0057] Example 2: The present application provides a preparation method of a zwitterionic cellulose-based solid-state electrolyte film, comprising the following steps:

[0058] (1) Take 20 g of a 1.0 wt.% mass fraction ZCNF aqueous solution, then add 2 mL of copper sulfate solution (containing 0.40 g of copper sulfate) under stirring, and make the solution into a uniform paste by constant stirring and dispersing, then add 1 mL of LiTFSI PEG-DME 250 over-saturated solution (containing 0.35 g of LiTFSI), which acts as a fiber binder and lithium ion conducting medium, after uniform stirring for 5 h, add two drops of ethylene glycol as a plasticizer to ensure the flexibility of the fiber after film formation, to obtain a paste-like ZCNF-CuSO4-containing precursor;

[0059] (2) Pour the above paste-like ZCNF-CuSO4-containing precursor into a polytetrafluoroethylene mold, place it in a 30°C blast oven for 16 h to dry and form a film, then take it out, cut it into a 19 mm round piece with a cutting machine, replace the residual water in the fiber film with N-methyl pyrrolidone (NMP) solvent, and finally evaporate the NMP in an oven to obtain a solid-state precursor;

[0060] (3) Soak the above solid-state precursor in a 1 mol / L LiTFSI in DOL / DME=1:1 lithium salt electrolyte for 70 h for ion exchange to insert Li + into the ZCNF-CuSO4 to obtain a Li-ZCNF-CuSO4-containing cellulose-based material;

[0061] (4) The cellulose-based material containing Li-ZCNF-CuSO4 is placed in a glove box to dry and evaporate the solvent to obtain the zwitterionic cellulose-based solid electrolyte membrane.

[0062] Example 3: The present application provides a preparation method of a zwitterionic cellulose-based solid electrolyte membrane, comprising the following steps:

[0063] (1) Take 20 g of a 1.5 wt.% ZCNF aqueous solution, then add 2 mL of a copper sulfate solution (containing 0.50 g of copper sulfate) under stirring, and make the solution into a uniform paste by constant stirring and dispersing, then add 1 mL of LiTFSI in PEG-DME 250 over-saturated solution (containing 0.45 g of LiTFSI), which acts as a fiber binder and lithium ion conducting medium, add two drops of glycerol as a plasticizer after 7 h of uniform stirring to ensure the flexibility of the fiber after film formation, to obtain a paste-like ZCNF-CuSO4-containing precursor;

[0064] (2) Pour the paste-like ZCNF-CuSO4-containing precursor into a polytetrafluoroethylene mold, place it in a 60°C air oven for 12 h to dry and form a film, then take it out, cut it into a 19 mm diameter disc using a disc cutter, then wash and replace the residual water in the fiber membrane with propanol, and finally evaporate the propanol in an oven to obtain a solid precursor;

[0065] (3) Soak the above solid precursor in a 1 mol / L LiTFSI in DOL / DME=1:1 lithium salt electrolyte for 96 h for ion exchange to insert Li + into ZCNF-CuSO4 to obtain a cellulose-based material containing Li-ZCNF-CuSO4;

[0066] (4) The cellulose-based material containing Li-ZCNF-CuSO4 is placed in a glove box to dry and evaporate the solvent to obtain the zwitterionic cellulose-based solid electrolyte membrane.

[0067] The zwitterionic cellulose-based solid electrolyte membrane prepared in Example 1 was tested for electrochemical performance, with PEO solid electrolyte as a control group, and the electrochemical impedance and lithium ion transference number of both were tested. The test method is as follows: the zwitterionic cellulose-based solid electrolyte membrane is cut into a 2.5 cm wide and 7 cm long strip, wrapped with copper foil at both ends, and the length of the exposed electrolyte membrane between the copper foils is 5 cm, then a stainless steel electrode clamp is clamped on the copper foil for testing, and the frequency range is 0.01 HZ~106 HZ. The resistance of the electrolyte membrane is inferred from the actual axis intercept of the EIS curve, and the ionic conductivity of the gel can be calculated according to formula (1-1).

[0068] (1-1);

[0069] wherein, is the ionic conductivity, L is the length of the sample in the direction of ion movement (the thickness of the electrolyte film), Rb is the resistance of the electrolyte film, and S is the area allowed for the ions to pass through the sample (the contact area of the copper foil and the electrolyte).

[0070] The test results of the electrochemical impedance are shown in Figures 4-6 . Compared with Figure 4 and Figure 5 , the electrochemical impedance of the zwitterionic cellulose-based solid electrolyte film is much lower than that of the PEO solid electrolyte at room temperature of 30-70℃, and the calculated ionic conductivity at room temperature reaches 1.01×10 –4 Scm –1 , while the ionic conductivity of the PEO solid electrolyte at room temperature is only 6.7×10 –6 Scm –1 .

[0071] Figure 6 As shown in , compared with the PEO solid electrolyte, the impedance value of the zwitterionic cellulose-based solid electrolyte film does not change significantly with temperature, proving that the solid electrolyte film prepared by the application has excellent temperature stability.

[0072] Figure 7 The test results of the lithium ion transference number are shown in Figure 8 and , and the calculated lithium ion transference number of the zwitterionic cellulose-based solid electrolyte film at 25℃ is 0.36, which is significantly higher than that of the PEO solid electrolyte of 0.20, proving that the zwitterionic cellulose-based solid electrolyte film has a relatively excellent lithium ion transference number.

[0073] (1-2);

[0074] wherein, is the applied 10 mV polarization voltage, I o and I s are the currents at the initial state and the steady state, respectively, R o and R s are the electrode resistances at the initial state and the steady state, respectively.

[0075] The zwitterionic cellulose-based solid electrolyte film prepared in Example 1 was matched with lithium sheets to assemble a Li|Li-ZCNF-CuSO4|Li symmetrical battery, and the interface stability between the zwitterionic cellulose-based solid electrolyte film and the lithium metal negative electrode was tested. The Li|Li-ZCNF-CuSO4|Li symmetrical battery was tested at a current density of 0.2 mAcm -2The changes of electrochemical impedance spectroscopy (EIS) during the cycling process at a current density of 0.2 mA / cm2, and the test conditions are as follows: the current density is 0.2 mA / cm2, and the charging and discharging time is alternated every half hour.

[0076] The interface stability test results are shown in Figures 9-11 . Referring to Figure 9 , the results show that during 80 cycles, the impedance of the symmetric battery remains at a low level, and the fluctuation range is small, and there is no obvious upward trend, indicating that the internal charge transfer of the symmetric battery is efficient, and the electrode / electrolyte interface is stable.

[0077] Figure 10 The inset in FIG. 1 is an equivalent circuit, R b represents the impedance of the electrolyte body, R SEI is the SEI film impedance, R ct is the charge transfer impedance, W is the diffusion impedance, and the interface impedance R SSE / Li between the electrolyte and the lithium metal negative electrode is R ct + R SEI . By fitting the equivalent circuit, the value of R SSE / Li can be obtained, the high-frequency region in the Nyquist plot corresponds to the bulk impedance R b , the semicircular arc in the medium-frequency region is the sum of R ct and R SEI , and the low-frequency region is the diffusion resistance W. The specific fitting results are shown in Table 2.

[0078] From Figure 11 and Table 2, first, R b does not change significantly during the cycling process, which proves that the electrolyte remains stable during the cycling process and no obvious lithium dendrite puncture occurs; second, R SSE / Li first increases slightly and then decreases during the cycling process, but remains stable overall during the cycling process, which proves that the zwitterionic cellulose-based solid electrolyte membrane and the lithium metal negative electrode maintain good interface stability.

[0079] Table 2 Impedance fitting results of Li|Li-ZCNF-CuSO4|Li symmetric battery at 0.2 mA cm –2 under different cycle numbers

[0080]

[0081] The electrochemical impedance, critical current density and long cycle performance of the Li|Li-ZCNF-CuSO4|Li symmetric battery were tested, and the Li|PEO|Li symmetric battery was used as a control group. The frequency range for electrochemical impedance testing is 105-10 -1Hz, with an amplitude of 10 mv. The test process of the critical current density test was as follows: first, the battery was pre-circulated twice at a low current density of 0.1 mA / cm2, and the current density was gradually increased by a step-by-step method, with an increase of 0.1 mA / cm2 each time, and 1 h of constant current charging and 1 h of constant current discharging were performed at each current density. The test process of the long cycle test was as follows: the battery was charged and discharged at a current density of 0.2 mA cm –2 . –2 .

[0082] The results are shown in Table 1. Figures 12-15 Figure 12 Figure 13 Compared with Li|PEO|Li symmetric battery, the results show that the electrochemical impedance of Li|Li-ZCNF-CuSO4|Li symmetric battery is much smaller.

[0083] Figure 14 As shown in Table 2, the critical current density of Li|Li-ZCNF-CuSO4|Li symmetric battery at 25°C reached 0.6 mA cm -2 .

[0084] Figure 15 As shown in Table 3, Li|Li-ZCNF-CuSO4|Li symmetric battery can be stably cycled for nearly 1500 h, and the overpotential during the cycle is less than 0.1 V, which performs much better than Li|PEO|Li symmetric battery.

[0085] The zwitterionic cellulose-based solid-state electrolyte film prepared in Example 1 was matched with LiFePO4 cathode material (LFP) to assemble lithium metal full battery (LFP|Li-ZCNF-CuSO4|Li) for rate performance (cycle test at 0.2C-5C rate) and long cycle test. The preparation process of the lithium metal full battery was as follows: the cathode material was prepared by mixing 70 wt.% lithium iron phosphate (LiFePO4, theoretical specific capacity 170 mAh g –1 , 20 wt.% PEO / LiTFSI (anhydrous acetonitrile as solvent), 10 wt.% Super P with anhydrous acetonitrile for 12 h, then the slurry was coated on the carbon-coated aluminum foil, and it was placed in a 60 °C oven for drying for 12 h, and the obtained electrode piece was cut into a 12 mm diameter circle for assembling a button cell, and the average load of the circular electrode piece was about 2 mg cm –2 ; the anode used lithium sheet. The test process of the long cycle test was as follows: after activating the battery for 2 cycles at a charge-discharge rate of 0.1C, the long cycle test was carried out at a charge-discharge rate of 0.5C, and the full battery voltage interval was [2.5V, 3.8V].

[0086] The results are shown in Table 4. Figures 16 to 18 ​​as shown. Figure 16 and Figure 17 As shown, during the initial test, due to solid-solid contact, the interface is not completely matched, there is a process of capacity rising, and then gradually stabilized, when the current intensity is raised to 2C, the capacity is still maintained at a level close to 110mAhg –1 , and then falls back to 0.2C, it can still maintain a high capacity level, even when the current intensity is raised to 5C level, it still maintains a capacity close to 84.05mAhg -1 , the battery still does not short circuit and can be stably cycled.

[0087] Figure 18 As shown, the full battery can be stably cycled for nearly 700 cycles without obvious capacity attenuation, which proves that the zwitterionic cellulose-based solid electrolyte film of the application can be adapted to lithium metal full battery.

[0088] The raw materials and equipment used in the application are conventional raw materials and equipment in the art unless otherwise specified; the methods used in the application are conventional methods in the art unless otherwise specified.

[0089] The above is only a preferred embodiment of the application, and does not limit the application in any way. Any simple modification, change and equivalent transformation of the above embodiment according to the technical essence of the application still belongs to the protection scope of the technical solution of the application.

Claims

1. A method for producing a zwitterionic cellulose-based solid-state electrolyte membrane, characterized by, The method comprises the following steps: S1: mixing ZCNF and copper sulfate in an aqueous solution to form a mixture, and then adding a lithium salt to the mixture to react, to obtain a precursor containing ZCNF-CuSO4; wherein the ZCNF is a zwitterionic cellulose nanofiber containing quaternary ammonium salt cation groups and carboxylate anion groups; S2: after drying the precursor containing ZCNF-CuSO4, ion exchange reaction is performed with a lithium salt electrolyte to obtain a cellulose-based material containing Li-ZCNF-CuSO4; S3: drying and treating the cellulose-based material containing Li-ZCNF-CuSO4 to obtain a zwitterionic cellulose-based solid electrolyte membrane.

2. The method for preparing a zwitterionic cellulose-based solid-state electrolyte membrane according to claim 1, characterized by, In step S1, the ZCNF is 20-30 parts by weight, and the copper sulfate is 40-50 parts by weight.

3. The method for preparing a zwitterionic cellulose-based solid electrolyte membrane according to claim 1, characterized in that, In step S1, the lithium salt is dissolved in polyethylene glycol dimethyl ether to form a supersaturated solution of the lithium salt, and then added to the mixture for reaction, wherein the lithium salt includes lithium bis(trifluoromethanesulfonyl)imide.

4. The method for preparing a zwitterionic cellulose-based solid electrolyte membrane according to claim 1, characterized in that, In step S1, the weight ratio of the zwitterionic cellulose nanofiber ZCNF to the lithium salt is 1:2-3.

5. A method for preparing a zwitterionic cellulose-based solid electrolyte membrane according to claim 1, characterized in that, In step S2, the precursor containing ZCNF-CuSO4 is soaked in the lithium salt electrolyte for 48-96 hours.

6. A method for preparing a zwitterionic cellulose-based solid electrolyte membrane according to claim 5, characterized in that, In the lithium salt electrolyte, the lithium salt includes lithium bis(trifluoromethanesulfonyl)imide, and the solvent includes a mixed solution of 1,3-dioxolane and dimethoxyethane.

7. A zwitterionic cellulose-based solid-state electrolyte membrane, characterized by, The zwitterionic cellulose-based solid electrolyte membrane is prepared by the method of any one of claims 1-6.

8. Use of a zwitterionic cellulose-based solid-state electrolyte membrane in a solid-state lithium metal battery, characterized in that The zwitterionic cellulose-based solid electrolyte membrane is prepared by the method of any one of claims 1-6.

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