CN115799623A - Fibrous composite solid electrolyte and preparation method and application thereof - Google Patents
Fibrous composite solid electrolyte and preparation method and application thereof Download PDFInfo
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Abstract
The invention provides a fibrous composite solid electrolyte and a preparation method and application thereof, the fibrous composite solid electrolyte comprises an electronic conducting part and an ionic conducting part, the electronic conducting part is provided with a net structure, the material of the ionic conducting part is filled in the pores of the net structure, the preparation raw material of the electronic conducting part comprises a carbon material precursor, and the material of the ionic conducting part comprises an inorganic solid electrolyte; the fibrous composite solid electrolyte has the ion and electron dual conduction effect, combines long-range conduction and short-range conduction, has higher conductivity and lower interface impedance, and can be used as a conductive agent of an electrode material, so that a battery prepared from the electrode material has excellent electrical properties.
Description
Technical Field
The invention belongs to the technical field of batteries, and particularly relates to a fibrous composite solid electrolyte as well as a preparation method and application thereof.
Background
The anode and cathode materials of the alkali metal battery are mostly composed of active substances, conductive agents and binders; the conductive agent provides electronic conductivity and becomes a key component forming a conductive network of a positive electrode material and a negative electrode material, the ionic conduction is solved by electrolyte permeating into the conductive network, the combination of the ionic conduction and the electronic conduction can basically be competent for the conventional charge and discharge process under the condition of small load of the current counter electrode, but the charge and discharge performance of a thick electrode which is required to pursue a high-energy-density battery as a guide is influenced to a certain extent, and meanwhile, if the solid electrode is designed, the battery is not added with the electrolyte, the design of an ionic conduction path is required to be introduced.
The solid electrolyte is used as a core part of solid and semi-solid batteries, mainly comprises a polymer solid electrolyte and an inorganic solid electrolyte, and is mainly used as a carrier for ion transportation. Common inorganic solid electrolytes include sulfide solid electrolytes, oxide solid electrolytes, and the like. The oxide solid electrolyte material has the advantages of high safety performance, good stability, low cost, environmental friendliness and the like, and mainly comprises an NASICON-type structure oxide electrolyte, a garnet-structure oxide electrolyte and a perovskite-structure oxide electrolyte; the sulfide solid electrolyte has the characteristics of high room-temperature ionic conductivity, low electronic conductivity, good mechanical property and the like. Oxide and sulfide solid electrolytes are also the most interesting inorganic solid electrolyte materials for the development of all-solid batteries at present. CN111816916A discloses a composite solid electrolyte membrane, a preparation method thereof and a lithium ion battery, the invention provides a composite solid electrolyte membrane, which comprises a polymer electrolyte and inorganic electrolyte fibers dispersed in the polymer electrolyte, wherein an included angle θ between the length direction of the inorganic electrolyte fibers and the thickness direction of the composite solid electrolyte membrane satisfies: theta is more than or equal to 0 degree and less than or equal to 30 degrees. The composite solid electrolyte membrane obtained by the invention improves the ionic conductivity and the mechanical strength of the composite solid electrolyte membrane by designing the material composition and the structure.
However, since the inorganic solid electrolyte has high rigidity, is not favorable for pore filling and interface contact with an electrode, and cannot provide long-range conductivity, and the polymer solid electrolyte has low conductivity, the conventional inorganic solid electrolyte and polymer solid electrolyte cannot have both excellent conductivity and low interface resistance.
Therefore, it is an urgent technical problem in the art to develop a fibrous composite solid electrolyte with high conductivity, good toughness and low interfacial resistance with electrodes.
Disclosure of Invention
In view of the defects of the prior art, the present invention aims to provide a fibrous composite solid electrolyte and a preparation method thereof, wherein the fibrous composite solid electrolyte combines electronic conduction and ionic conduction, so that the fibrous composite solid electrolyte has the advantages of both the electronic conduction and the ionic conduction, realizes the dual conduction effect of ions and electrons, and has high conductivity and low interface impedance, so that a battery prepared by using the fibrous composite solid electrolyte has excellent electrical properties.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a fibrous composite solid electrolyte comprising an electronically conductive portion and an ionically conductive portion;
the electron conducting part has a mesh structure, and the material of the ion conducting part is filled in the pores of the mesh structure;
the raw material for preparing the electronic conducting part comprises a carbon material precursor, and the material of the ionic conducting part comprises an inorganic solid electrolyte.
The fibrous composite solid electrolyte provided by the invention comprises an electronic conducting part and an ionic conducting part, wherein the electronic conducting part is provided with a continuous net structure, a large number of continuous holes are formed in the net structure, and the ionic conducting part is filled in the holes of the holes, so that the electronic conducting and the ionic conducting are combined to realize the double conduction effect, the conduction capability of the ionic conducting and the electronic conducting is improved, the combination of long-range conducting and short-range conducting is realized, the finally obtained fibrous composite solid electrolyte has higher conductivity, higher compaction density, better flexibility and proper porosity, and the impedance with an electrode interface is smaller.
The fibrous composite solid electrolyte provided by the invention can completely or partially replace a conductive agent to be filled into an electrode material, so that the using amount of the traditional conductive agent is reduced, the mass ratio of active substances in the electrode material is improved, the using amount of an electrolyte is reduced, the fibrous composite solid electrolyte is particularly suitable for thick electrodes (more than 200 mu m), and the battery prepared by adopting the electrode material has excellent electrical properties.
The fibrous composite solid electrolyte preferably has a diameter of 5 to 5000nm, for example 10nm, 50nm, 100nm, 500nm, 1000nm, 2000nm, 3000nm, 4000nm or the like, more preferably 50 to 500nm, for example 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm or the like.
The aspect ratio of the fibrous composite solid electrolyte is preferably 2 to 100, for example, 10, 20, 30, 40, 50, 60, 70, 80, or 90, and more preferably 5 to 50.
Preferably, the fibrous composite solid electrolyte has a porosity of less than 20%, such as 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, or 10%, etc.
Preferably, the mass ratio of the electron-conducting portion to the ion-conducting portion is 1 (0.1 to 9), for example, 1.
Preferably, the carbon material precursor includes a polymer material.
Preferably, the polymeric material comprises any one of polyacrylonitrile, polyvinylpyrrolidone, polyurethane or polyimide or a combination of at least two of them.
Preferably, the inorganic solid electrolyte includes any one of an oxide solid electrolyte, a sulfide solid electrolyte, or a chloride solid electrolyte, or a combination of at least two thereof.
Preferably, the oxide solid electrolyte comprises any one of a NASICON-type oxide solid electrolyte, a garnet-type oxide solid electrolyte, or a perovskite-type oxide solid electrolyte or a combination of at least two thereof.
Preferably, the NASICON-type oxide solid electrolyte includes any one of lithium aluminum titanium phosphate, lithium germanium phosphate, or lithium zirconium phosphate, or a combination of at least two thereof.
Preferably, the garnet-type oxide solid electrolyte comprises lanthanum lithium zirconium oxide.
Preferably, the perovskite-type oxide solid-state electrolyte includes lanthanum lithium titanium oxide.
Preferably, the sulfide solid electrolyte includes a Li-P-S type solid electrolyte, li 11-n M 2-n P 1+n S 12 Type solid electrolyte or Li 6 PS 5 Any one or a combination of at least two of the X-type solid electrolytes,
wherein n is more than 0 and less than or equal to 1, M is selected from Ge, sn or Si, and X is selected from Cl, br or I.
Preferably, the Li-P-S type solid electrolyte includes Li 3 PS 4 And/or Li 7 P 3 S 11 。
Preferably, the Li 11-n M 2-n P 1+n S 12 The solid electrolyte comprises Li 2 S-GeS 2 -P 2 S 5 。
Preferably, the material of the electron conducting portion further comprises carbon nanotubes;
preferably, the mass ratio of the carbon material precursor to the carbon nanotubes is 1 (0.1 to 9), for example, 1.
In a second aspect, the present invention provides a method for producing a fibrous composite solid electrolyte according to the first aspect, comprising the steps of:
(1) Dissolving a carbon material precursor and optionally a carbon nano tube in a solvent, adding an inorganic solid electrolyte, and mixing to obtain an electrostatic spinning solution;
(2) And (2) carrying out electrostatic spinning on the electrostatic spinning stock solution obtained in the step (1), and carrying out stabilizing treatment, carbonizing treatment and shearing treatment to obtain the fibrous composite solid electrolyte.
Dissolving a carbon material precursor and optionally a carbon nano tube in a solvent, adding an inorganic solid electrolyte, mixing to uniformly disperse powder particles of the inorganic solid electrolyte in a liquid to obtain an electrostatic spinning stock solution, spinning the obtained electrostatic spinning stock solution through electrostatic spinning to obtain composite fibers, stabilizing and carbonizing the obtained composite fibers to form the carbon material precursor into a carbon material, and optionally forming an electronic conductive part with a net structure with the carbon nano tube, wherein the inorganic solid electrolyte is filled in holes of the net structure to serve as an ionic conductive part; the preparation method is simple in process and suitable for batch industrial production.
Preferably, the solvent of step (1) comprises N, N-dimethylformamide.
Preferably, the mixing of step (1) is carried out under stirring.
Preferably, the mixing time in step (1) is 3 to 5 hours, such as 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, or 4.8 hours, etc.
Preferably, the temperature of the mixing in step (1) is 50 to 70 ℃, such as 52 ℃, 54 ℃, 56 ℃, 58 ℃, 60 ℃, 62 ℃, 64 ℃, 66 ℃ or 68 ℃ and the like.
Preferably, the voltage of the electrostatic spinning in the step (2) is 50-70 kV, such as 52kV, 54kV, 56kV, 58kV, 60kV, 62kV, 64kV, 66kV or 68 kV.
Preferably, the electrospinning in step (2) has a spinning distance of 10 to 20cm, such as 11cm, 12cm, 13cm, 14cm, 15cm, 16cm, 17cm, 18cm or 19cm, etc.
Preferably, the stabilizing treatment and the carbonizing treatment in step (2) are both carried out in a tube furnace.
Preferably, the stabilizing treatment and the carbonizing treatment in the step (2) are carried out under the protection of inert gas.
Preferably, the inert gas comprises argon.
Preferably, the temperature of the stabilization treatment in step (2) is 400 to 500 ℃, for example, 410 ℃, 420 ℃, 430 ℃, 440 ℃,450 ℃, 460 ℃, 470 ℃, 480 ℃, or 490 ℃.
Preferably, the stabilizing treatment in step (2) is carried out for 1.5-2.5 h, such as 1.6h, 1.7h, 1.8h, 1.9h, 2h, 2.1h, 2.2h, 2.3h or 2.4 h.
Preferably, the temperature of the carbonization treatment in step (2) is 800 to 1000 ℃, such as 820 ℃, 840 ℃, 860 ℃, 880 ℃, 900 ℃, 920 ℃, 940 ℃, 960 ℃, 980 ℃ or the like.
Preferably, the carbonization treatment time in the step (2) is 1.5-2.5 h, such as 1.6h, 1.7h, 1.8h, 1.9h, 2h, 2.1h, 2.2h, 2.3h or 2.4 h.
Preferably, the shearing treatment method in step (2) comprises high energy ball milling.
As a preferred technical scheme of the invention, the preparation method comprises the following steps:
(1) Dissolving a carbon material precursor and optionally a carbon nano tube in a solvent, adding an inorganic solid electrolyte, stirring and mixing for 3-5 h at 50-70 ℃ to obtain an electrostatic spinning stock solution;
(2) And (2) carrying out electrostatic spinning on the electrostatic spinning stock solution obtained in the step (1) under the voltage of 50-70 kV, wherein the spinning distance is 10-20 cm, carrying out stabilizing treatment at 400-500 ℃ for 1.5-2.5 h and carbonizing treatment at 800-1000 ℃ for 1.5-2.5 h under the protection of argon, and carrying out high-energy ball milling to obtain the fibrous composite solid electrolyte.
In a third aspect, the present invention provides an electrode material comprising an active material, a binder and the fibrous composite solid electrolyte of the first aspect.
Preferably, the electrode material comprises a positive electrode material or a negative electrode material.
In a fourth aspect, the present invention provides a use of the electrode material according to the third aspect in an alkali metal battery.
Compared with the prior art, the invention has the following beneficial effects:
(1) The fibrous composite solid electrolyte provided by the invention comprises an electronic conducting part and an ionic conducting part, wherein the electronic conducting part is provided with a continuous net structure, a large number of continuous holes are formed in the net structure, and the ionic conducting part is filled in the holes of the holes, so that the fibrous composite solid electrolyte realizes the dual conduction effect of electronic conduction and ionic conduction, improves the conduction capability of the ionic conduction and the electronic conduction, and simultaneously realizes the combination of long-range conduction and short-range conduction, so that the obtained fibrous composite solid electrolyte has higher compaction density, better flexibility, proper porosity and higher conductivity, and simultaneously has smaller impedance with an electrode interface.
(2) The fibrous composite solid electrolyte provided by the invention can replace or partially replace a conductive agent to be filled into an electrode material, so that the using amount of the traditional conductive agent is reduced, the mass ratio of active substances in the electrode material is improved, the using amount of an electrolyte is reduced, the fibrous composite solid electrolyte is particularly suitable for thick electrodes, and the electrical property of a battery prepared by the electrode material can be effectively improved; specifically, the interface impedance of the lithium ion battery prepared by the fibrous composite solid electrolyte provided by the invention is only 4.3-4.6 m omega, and the capacity retention rate is up to 92-93% after 500 cycles.
Detailed Description
The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitation of the present invention.
Example 1
A fibrous composite solid electrolyte, is made up of electron conducting part and ion conducting part with the mass ratio of 1, its diameter is 250nm, the length-diameter ratio is 50, its preparation method includes the following steps:
(1) Dissolving 22g of polyacrylonitrile (Aladdin reagent (Shanghai) Co., ltd., P303197) and 3g of conductive carbon tube (Qingdao Haoxin New energy science Co., ltd., HX-NS) in 200mL of N, N-dimethylformamide, adding 10g of lithium aluminum titanium phosphate, and magnetically stirring and mixing at 60 ℃ for 4 hours to obtain an electrostatic spinning stock solution;
(2) And (2) performing electrostatic spinning on the electrostatic spinning stock solution obtained in the step (1), wherein the voltage of the electrostatic spinning is 60kV, the spinning distance is 15cm, then placing the electrostatic spinning stock solution into a tube furnace, performing stabilization treatment for 2h at 450 ℃ and carbonization treatment for 2h at 900 ℃ in the argon atmosphere, and performing high-energy ball milling to obtain the fibrous composite solid electrolyte.
Example 2
A fibrous composite solid electrolyte, is made up of electron-conducting and ion-conducting part with the mass ratio of 1, its diameter is 50nm, the length-diameter ratio is 5, its preparation method includes the following steps:
(1) Dissolving 12g of polyacrylonitrile (Aladdin reagent (Shanghai) Co., ltd., P303197) and 3g of conductive carbon tube (Qingdao Haoxin New energy science Co., ltd., HX-NS) in 180mL of N, N-dimethylformamide, adding 10g of lithium aluminum titanium phosphate, and magnetically stirring and mixing at 50 ℃ for 5 hours to obtain an electrostatic spinning stock solution;
(2) And (2) performing electrostatic spinning on the electrostatic spinning solution obtained in the step (1), wherein the electrostatic spinning voltage is 50kV, the spinning distance is 15cm, then placing the electrostatic spinning solution into a tube furnace, performing stabilization treatment for 2.5h at 400 ℃ and carbonization treatment for 1.5h at 1000 ℃ in the argon atmosphere, and performing high-energy ball milling to obtain the fibrous composite solid electrolyte.
Example 3
A fibrous composite solid electrolyte, is made up of electron-conducting and ion-conducting part with the mass ratio of 2, its diameter is 500nm, the length-diameter ratio is 50, its preparation method includes the following steps:
(1) Dissolving 18g of polyvinylpyrrolidone (Aladdin reagent (Shanghai) Co., ltd., K88-96) and 3g of conductive carbon tubes (Qingdao Haoxin New energy technology Co., ltd., HX-NS) in 200mL of N, N-dimethylformamide, adding 12g of titanium lanthanum lithium oxide, and magnetically stirring and mixing for 3 hours at 70 ℃ to obtain an electrostatic spinning stock solution;
(2) And (2) performing electrostatic spinning on the electrostatic spinning stock solution obtained in the step (1), wherein the voltage of the electrostatic spinning is 70kV, the spinning distance is 15cm, then placing the electrostatic spinning stock solution into a tube furnace, performing stabilization treatment for 1.5h at 500 ℃ and carbonization treatment for 2.5h at 800 ℃ in the argon atmosphere, and performing high-energy ball milling to obtain the fibrous composite solid electrolyte.
Example 4
A fibrous composite solid electrolyte differing from example 1 only in that no carbon nanotube was added, and the other structure, material and preparation method were the same as example 1.
Comparative example 1
A fibrous solid electrolyte with a diameter of 250nm and an aspect ratio of 50, the preparation method comprises the following steps:
(1) Dissolving 22g of polyacrylonitrile (Aladdin reagent (Shanghai) Co., ltd.), P303197 and 3g of conductive carbon tube (Qingdao Hao Xin New energy science Co., ltd., HX-NS) in 200mL of N, N-dimethylformamide to obtain an electrostatic spinning stock solution;
(2) And (2) performing electrostatic spinning on the electrostatic spinning stock solution obtained in the step (1), wherein the voltage of the electrostatic spinning is 60kV, the spinning distance is 15cm, then placing the electrostatic spinning stock solution into a tube furnace, performing stabilization treatment for 2h at 450 ℃ and carbonization treatment for 2h at 900 ℃ in the argon atmosphere, and performing high-energy ball milling to obtain the fibrous solid electrolyte.
Comparative example 2
A fibrous solid electrolyte with a diameter of 250nm and an aspect ratio of 50, the preparation method comprises the following steps:
(1) Adding 12g of lithium aluminum titanium phosphate into 200mL of N, N-dimethylformamide, and magnetically stirring and mixing at 60 ℃ for 4h to obtain an electrostatic spinning stock solution
(2) And (2) performing electrostatic spinning on the electrostatic spinning solution obtained in the step (1), wherein the electrostatic spinning voltage is 60kV, the spinning distance is 15cm, then placing the electrostatic spinning solution into a tube furnace, performing stabilization treatment for 2 hours at 450 ℃ and carbonization treatment for 2 hours at 900 ℃ in the argon atmosphere, and performing high-energy ball milling to obtain the fibrous solid electrolyte.
Application example 1
A preparation method of the positive pole piece comprises the following steps:
(1) Adding 41.5g of PVDF and 1.3L of NMP into a stirrer in sequence, stirring for 3h at a high-speed rotation speed of 4000rpm and a revolution speed of 70rpm, adding 10.4g of Super P, 208g of carbon nanotube conductive slurry (solid content is 5%) and 10.4g of fibrous composite solid electrolyte (example 1) in sequence, mixing for 1h at a high speed, adding 2000g of lithium iron phosphate, and stirring for 6h at a high speed to obtain anode slurry;
(2) The positive electrode slurry obtained in the step (1) is uniformly distributed according to the surface density of 320g/m 2 Coating the aluminum foil with the coating solution, and cutting the aluminum foil with a cutting die to obtain the positive pole piece.
Application examples 2 to 4
A positive electrode sheet differing from application example 1 only in that the fibrous composite solid electrolytes obtained in examples 2 to 4 were used instead of the fibrous composite solid electrolyte obtained in example 1, and the other materials and preparation methods were the same as in application example 1.
Application example 5
A preparation process of the lithium ion battery comprises the following steps:
(1) Preparing anode slurry: sequentially adding 175.4g of LA132 with the solid content of 15%, 10.5g of CMC and 1.14L of deionized water into a stirrer, stirring for 3 hours at a high-speed rotation speed of 4000rpm and a revolution speed of 70rpm, sequentially adding 15.8g of Super P, performing high-speed mixing for 1 hour, adding 1000g of artificial graphite, and stirring for 6 hours at a high speed to obtain negative electrode slurry;
(2) Preparing an electrolyte: liPF was added in a concentration of 1mol/L in a glove box filled with argon 6 Dissolving the mixture in an electrolyte composed of EC, EMC and DMC in a volume ratio of 1;
(3) Manufacturing the battery: (1) coating, baking and cutting the negative electrode slurry to obtain a negative electrode plate; (2) a battery roll core is manufactured in the sequence that a negative pole piece is wrapped by a diaphragm, the negative pole piece is wrapped by the diaphragm, and the diaphragm wraps a positive pole piece (application example 1); (3) a winding core is welded with a tab, the positive tab is aluminum, and the negative tab is nickel/copper plated with nickel; (4) packaging the winding core in an aluminum plastic film, and reserving a port on the side edge for subsequent liquid injection; (5) placing the packaged battery cell in a 110 ℃ blast oven to bake for 48h; (6) transferring the baked battery cell to a liquid injection room in a-30 ℃ dew point environment under a low dew point environment, and injecting a proper amount of electrolyte; (7) and sealing the battery cell, and then aging, forming and grading to obtain the lithium ion battery.
Application examples 6 to 8
A lithium ion battery, which is different from application example 5 only in that the positive electrode plate obtained in application example 1 is replaced by the positive electrode plate obtained in application examples 2 to 4, and other materials and preparation methods are the same as those in application example 5.
Comparative application examples 1 to 2
A positive electrode plate is different from application example 1 only in that the fibrous composite solid electrolyte obtained in example 1 is replaced by the fibrous composite solid electrolyte obtained in comparative examples 1 to 2, and other materials and preparation methods are the same as application example 1.
Comparative application examples 3 to 4
A lithium ion battery, which is different from application example 5 only in that the positive electrode plate obtained in application example 1 is replaced by the positive electrode plate obtained in comparative application examples 1 to 2, and other materials and preparation methods are the same as those of application example 5.
And (4) performance testing:
(1) Modulus of elasticity: mechanical properties were measured by instrumental nanoindentation (G200 nanometer indenter, KLA) at a constant strain rate of 0.05s -1 Under the condition of the formula 1/E r ＝(1-v 2 )/E+(1-v i 2 )/E i Determining the modulus of elasticity, where v and v i Poisson's ratio of the sample and indenter, respectively, ei is the modulus of elasticity of the indenter, E r ＝0.5S√(π/A c ) And S is the unloading slope of the load-displacement curve after the initial pressure head is removed.
(2) Ionic conductivity: assembling a button cell with a stainless steel/electrolyte/stainless steel structure in a glove box filled with argon, standing for 1d, and then carrying out electrochemical alternating current impedance spectroscopy test by adopting a Bio-logic VMP-300 electrochemical workstation, wherein the frequency range is 7 kHz-500 MHz, and the test temperature is 30-80 ℃;
the ionic conductivity (σ) was calculated using σ = L/RS, where L is the electrolyte membrane thickness in mm, R is the electrolyte resistance in ohm, S is the effective electrode surface area in mm 2 。
The solid electrolytes obtained in examples 1 to 4 and comparative examples 1 to 2 were tested according to the above test methods, and the test results are shown in table 1:
TABLE 1
| Modulus of elasticity/GPa | Ionic conductivity/S/cm | |
| Example 1 | 126 | 4.2×10 -4 |
| Example 2 | 135 | 4.1×10 -4 |
| Example 3 | 185 | 4.0×10 -4 |
| Example 4 | 128 | 4.1×10 -4 |
| Comparative example 1 | 115 | 3.8×10 -4 |
| Comparative example 2 | 113 | 3.9×10 -4 |
According to the data in the table 1, the fibrous composite solid electrolyte provided by the invention has excellent mechanical property and electrical property; the fibrous composite solid electrolytes obtained in examples 1 to 4 had elastic moduli of 126 to 185GPa and ionic conductivities of 4.0X 10 -4 ～4.2×10 -4 (ii) a While the solid electrolyte formed with only the electron-conducting portion (comparative example 1) and the solid electrolyte with only the ion-conducting portion (comparative example 2) had a lower elastic modulus and a lower ionic conductivity, indicating that both the mechanical and electrical properties were poor.
(3) And (3) impedance testing: the impedance test adopts a battery internal resistance tester (CHT 3561, changzhou city and general electronic technology Co., ltd.), red is connected with the anode, black is connected with the cathode, internal resistance test is selected, and then reading is carried out;
(4) Cycle performance: using the novice battery tester. The assembled lithium ion battery is arranged on a battery tester, the red is connected with the anode, the black is connected with the cathode, and then the battery is processed as follows: (1) standing for 12h; (2) constant current charging, wherein the current is 0.1C, and the cut-off voltage is 4.2V; (3) constant current discharge, current 0.1C, cut-off voltage 2.7V; (4) circulating for 500 times; (5) and (6) ending.
The lithium ion batteries provided in application examples 5 to 8 and comparative application examples 3 to 4 were tested according to the above test method, and the test results are shown in table 2:
TABLE 2
| Interface impedance/m omega | Capacity retention ratio/%) | |
| Application example 5 | 4.3 | 93 |
| Application example 6 | 4.4 | 92 |
| Application example 7 | 4.2 | 93 |
| Application example 8 | 4.6 | 91 |
| Comparative application example 3 | 4.7 | 89 |
| Comparative application example 4 | 5.2 | 88 |
As can be seen from the data in table 1: the lithium ion battery containing the composite solid electrolyte provided by the invention has excellent electrical properties, specifically, the interface impedance of the lithium ion battery obtained in application examples 5-8 is only 4.2-4.6 m omega, the capacity retention rate is as high as 92-93% after 500 cycles, the interface impedance of the lithium ion battery containing only the ion conductive part and the solid electrolyte containing only the electron conductive part is higher, and the cycle retention rate is lower, which indicates that the electrical properties are poor.
It can be seen from table 1 and table 2 that the fibrous composite solid electrolyte obtained by combining the electronic conductive part and the ionic conductive part is effectively improved in mechanical properties and ionic conductivity, and simultaneously, the interfacial impedance is reduced to a certain extent along with the construction of the composite conductive network, which indicates that the electronic conductivity of the battery is improved after the composite solid electrolyte is added.
The applicant states that the present invention is illustrated by the above examples to a fibrous composite solid electrolyte and a method of making and using the same, but the present invention is not limited to the above examples, i.e. it is not meant to imply that the present invention must be practiced by the above examples. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
Claims (10)
1. A fibrous composite solid electrolyte, characterized in that it comprises an electronically conductive portion and an ionically conductive portion;
the electron conducting part has a mesh structure, and the material of the ion conducting part is filled in the pores of the mesh structure;
the raw material for preparing the electronic conducting part comprises a carbon material precursor, and the material for the ionic conducting part comprises an inorganic solid electrolyte.
2. The fibrous composite solid electrolyte according to claim 1, characterized in that the fibrous composite solid electrolyte has a diameter of 5 to 5000nm, preferably 50 to 500nm;
preferably, the aspect ratio of the fibrous composite solid electrolyte is 2 to 100, more preferably 5 to 50;
preferably, the porosity of the fibrous composite solid electrolyte is less than 20%.
3. The fibrous composite solid electrolyte according to claim 1 or 2, wherein the mass ratio of the electron-conducting portion to the ion-conducting portion is 1 (0.1 to 9), preferably 1 (1 to 3.5);
preferably, the carbon material precursor comprises a polymeric material;
preferably, the polymer material comprises any one of polyacrylonitrile, polyvinylpyrrolidone, polyurethane or polyimide or a combination of at least two of them.
4. The fibrous composite solid electrolyte according to any one of claims 1 to 3, wherein the inorganic solid electrolyte comprises any one of an oxide solid electrolyte, a sulfide solid electrolyte or a chloride solid electrolyte or a combination of at least two thereof;
preferably, the oxide solid electrolyte comprises any one of a NASICON-type oxide solid electrolyte, a garnet-type oxide solid electrolyte, or a perovskite-type oxide solid electrolyte or a combination of at least two thereof;
preferably, the NASICON-type oxide solid electrolyte includes any one of lithium aluminum titanium phosphate, lithium germanium phosphate, or lithium zirconium phosphate, or a combination of at least two thereof;
preferably, the garnet-type oxide solid electrolyte comprises lithium lanthanum zirconium oxide;
preferably, the perovskite-type oxide solid electrolyte includes lanthanum lithium titanium oxide;
preferably, the sulfide solid state electrolyte includes Li-P-S type solid state electrolyte, li 11-n M 2-n P 1+n S 12 Type solid electrolyte or Li 6 PS 5 Any one or a combination of at least two of the X-type solid electrolytes,
wherein n is more than 0 and less than or equal to 1, M is selected from Ge, sn or Si, and X is selected from Cl, br or I;
preferably, the Li-P-S type solid electrolyte includes Li 3 PS 4 And/or Li 7 P 3 S 11 ；
Preferably, the Li 11-n M 2-n P 1+n S 12 The solid electrolyte comprises Li 2 S-GeS 2 -P 2 S 5 。
5. The fibrous composite solid electrolyte according to any one of claims 1 to 4, characterized in that the material of said electron-conducting portion further comprises carbon nanotubes;
preferably, the mass ratio of the carbon nanotubes to the carbon material precursor is 1 (0.1-9).
6. A method for producing the fibrous composite solid electrolyte according to any one of claims 1 to 5, characterized by comprising the steps of:
(1) Dissolving a carbon material precursor and optionally a carbon nano tube in a solvent, adding an inorganic solid electrolyte, and mixing to obtain an electrostatic spinning solution;
(2) And (2) carrying out electrostatic spinning on the electrostatic spinning stock solution obtained in the step (1), and carrying out stabilizing treatment, carbonizing treatment and shearing treatment to obtain the fibrous composite solid electrolyte.
7. The method according to claim 6, wherein the solvent of step (1) comprises N, N-dimethylformamide;
preferably, the mixing of step (1) is carried out under stirring;
preferably, the mixing time of the step (1) is 3-5 h;
preferably, the temperature of the mixing in step (1) is 50 to 70 ℃.
8. The production method according to claim 6 or 7, wherein the electrostatic spinning of step (2) is performed at a voltage of 50 to 70kV;
preferably, the spinning distance of the electrostatic spinning in the step (2) is 10-20 cm;
preferably, the stabilizing treatment and the carbonizing treatment in the step (2) are both carried out in a tube furnace;
preferably, the stabilizing treatment and the carbonizing treatment in the step (2) are carried out under the protection of inert gas;
preferably, the inert gas comprises argon;
preferably, the temperature of the stabilizing treatment in the step (2) is 400-500 ℃;
preferably, the stabilizing treatment time in the step (2) is 1.5-2.5 h;
preferably, the temperature of the carbonization treatment in the step (2) is 800-1000 ℃;
preferably, the carbonization treatment time in the step (2) is 1.5-2.5 h;
preferably, the shearing treatment method in step (2) comprises high energy ball milling.
9. An electrode material characterized by comprising an active material, a binder and the fibrous composite solid electrolyte according to any one of claims 1 to 5;
preferably, the electrode material comprises a positive electrode material or a negative electrode material.
10. Use of the electrode material according to claim 9 in an alkali metal battery.
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