WO2009140834A1

WO2009140834A1 - An organic/inorganic nanocomposite solid electrolyte and the preparing method of the same

Info

Publication number: WO2009140834A1
Application number: PCT/CN2008/072627
Authority: WO
Inventors: 杨文胜; 王健; 王立仕
Original assignee: 北京化工大学
Priority date: 2008-05-21
Filing date: 2008-10-09
Publication date: 2009-11-26
Also published as: CN101276658B; CN101276658A

Abstract

An organic/inorganic nanocomposite solid electrolyte and the preparing method of the same are provided. The nanocomposite solid electrolyte is composed by weight of poly(ethylene oxide) (PEO) 54%-91%, lithium percolate (LiClO₄) 6%-16%, and nanosheets of layered double hydroxides (LDHNS) 1%-30%. The nanocomposite solid electrolyte is prepared by sufficiently uniformly mixing PEO, LiClO₄and LDHNS in water and evaporating the water.

Description

Inorganic/organic nano composite solid electrolyte and preparation method thereof

The invention relates to an inorganic/organic nano composite solid electrolyte and a preparation method thereof, and belongs to the technical field of inorganic/organic nano composite materials and preparation thereof. Background technique

In a lithium ion battery, the use of a solid electrolyte has the advantages of being less liquid-relaxing, safer, and easier to install than using a liquid electrolyte, but the lower ion mobility and poor thermal stability of the solid electrolyte limit its actual production. application. Among many conductive polymer matrices, polyoxyethylene PEO is a fast ion conductor and a good solvent for lithium salts. It has the advantages of good chemical stability, easy availability of raw materials, and simple synthesis method. However, the unmodified pure PEO as a solid electrolyte has the following disadvantages: Firstly, because it belongs to a macromolecular polymer, the ionic conductivity is low due to the high crystallinity, which cannot meet the needs of lithium ion transport; secondly, as a pure organic substance, the material The thermal stability and mechanical properties have yet to be further improved.

Inorganic materials are widely used in the modification research of PEO. The inorganic fillers used to form the composite solid electrolyte mainly include A1 ₂ 0 ₃ , ZnO, BaTi0 ₃ , molecular sieves, montmorillonite and the like. Literature (1) Solid State Ionics, 2003, 156:1-2, Chu et al. introduced the mesoporous material MCM-41 with hexagonal pore structure into the PEO-LiC10 ₄ system, and obtained the mechanical properties of the composite solid electrolyte. Both the ionic conductivity and the ionic conductivity were significantly improved.

Hydrotalcite, also known as Layered Double Hydroxides (LDHs), is a typical anionic layered compound. LDHs can be stripped and stripped hydrotalcite nanosheets (LDHNS) It can be used for the preparation of intercalation materials and as an inorganic filler to be filled into organic materials, and has broad application prospects. In the literature (2) Chem. Commun., 2002, 15:60, O'Leary et al. prepared LDHs/poly-HEMA nanocomposites. Studies have shown that LDHs are uniformly filled into poly-HEMA with a single layer of laminate, and The thermal stability of LDHs/poly-HEMA composites is significantly higher than that of poly-HEMA.

However, the hydrotalcite nanosheet LDHNS is combined with the conductive polymer PEO to destroy the ordered arrangement of the PEO crystal, reduce its crystallinity, and improve the ionic conductivity and lithium ion migration number while improving the thermal stability of PEO. No related reports. Summary of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel inorganic/organic nanocomposite solid electrolyte and a preparation method therefor. The inorganic/organic nanocomposite solid electrolyte has good thermal stability, high room temperature conductivity and large lithium ion migration number, and can be used as an electrolyte for a solid state lithium ion battery.

The inorganic/organic nano composite solid electrolyte provided by the invention is composed of polyoxyethylene PEO, lithium perchlorate LiC10 ₄ and hydrotalcite nanosheet LDHNS, and its chemical composition is PEO/LiC10 ₄ /LDHNS, each component The mass fractions are 54% to 91%, 6% to 16%, and 1% to 30%, respectively (for example, in some embodiments of the present invention, PEO, LiC10 ₄ in the inorganic/organic nanocomposite solid electrolyte of the present invention And the quality scores of LDHNS are 54%~91%, 8%~16% and 1%~30% respectively. The chemical composition of the hydrotalcite nanosheet LDHNS is [M ²⁺ _1-x M ³⁺ _x (OH) ₂ ] ^x+ , and M ²⁺ represents the divalent metal ions Mg ²⁺ , Zn ²⁺ , Ni ²⁺ , Any one of Fe ²⁺ and Co ²⁺ is preferably Mg ²⁺ ; M ³⁺ represents a trivalent metal ion Al ³⁺ , Cr ³⁺ , Fe ³⁺ , V ³⁺ , Co ³⁺ , Ga Any of ³⁺ and Ti ³⁺ , preferably Al ³⁺ ; x+ is a positive charge of the hydrotalcite nanosheet LDHNS. X is the mole fraction of the trivalent metal ion M ³⁺ , which ranges from 0.2^x^0.4; more specifically X ranges from 0.2 xl/3.

Polyethylene oxide PEO, lithium perchlorate LiC10 ₄ and hydrotalcite nanosheet LDHNS are uniformly mixed in an aqueous solution at a certain mass ratio, and then the solvent is evaporated to obtain a PEO/LiC10 ₄ /LDHNS composite solid electrolyte. The specific process steps are:

A. Preparation of hydrotalcite nanosheets LDHNS sol

^Dissolving a soluble salt of M ^{2+ and} a soluble salt of M ^{3+ in} a molar ratio of M ²⁺ /M ³⁺ of 2:1 to 4:1 in deionized water de C0 ₂ to form a mixed salt solution, and Control metal ions (M ²⁺ +M ³⁺ ) total The concentration is from 0.10 to 2.4 mol/L (for example, in some embodiments of the invention, the concentration of M ²⁺ is controlled to be 0.10 to 1.60 mol/L); the molar ratio of NaOH to M ²⁺ is 5:1. The ratio of ~10:1 is dissolved in deionized water de C0 ₂ to prepare an alkali solution with a concentration of 0.50~10.0 mol/L; according to the molar amount of lactic acid, the amount of M ²⁺ moles is 1~10 times The lactic acid is dissolved in deionized water de C0 ₂ to prepare an aqueous lactic acid solution having a concentration of 0.20 to 16 mol/L (for example, in some embodiments of the present invention, the number of moles of lactic acid is M ²⁺ moles 2~10 times the dosage of lactic acid aqueous solution); the above mixed salt solution and alkali solution are simultaneously added to the lactic acid aqueous solution under the protection of N ₂ to obtain a slurry, and the pH of the system is maintained during the dropping process is 8-12, and then The slurry is crystallized under the protection of 40-100 ° C for 2 to 24 hours to obtain a hydrotalcite-intercalated hydrotalcite; the lactic acid intercalated hydrotalcite is washed with deionized water de C0 ₂ , and then at 8000-10000 High speed centrifugation 5 minutes to 20 revolutions / min rotation speed, the supernatant was removed, the solid precipitate with deionized water, removal of C0 ₂ After high speed centrifugation continued scrubber, the washing was repeated, high-speed centrifugation until the pH was 7 to 7.5. The solid precipitate obtained by high-speed centrifugation is refluxed for 8-10 hours in a boiling state to obtain an LDHNS sol, and the concentration thereof is adjusted to 1 to 10 g/L for use.

The soluble salt of M ²⁺ is any one of nitrates of Mg ²⁺ , Zn ²⁺ , Ni ²⁺ , Fe ²⁺ , and Co ²⁺ , preferably Mg(N0 ₃ ) _{2 ;} M ³⁺ The soluble salt is any one of nitrates of Al ³⁺ , Cr ³⁺ , Fe ³⁺ , V ³⁺ , Co ³⁺ , Ga ³⁺ , Ti ³⁺ , preferably A1(N0 ₃ ) ₃ . The deionized water for removing C0 ₂ may be specifically obtained by boiling deionized water for 5 to 10 minutes, and then naturally cooling to room temperature under standing conditions.

B. Preparation of inorganic/organic nanocomposite solid electrolyte

PEO and LiC10 ₄ in accordance with the mass ratio of 4: 1 to 12: 1 ratio of PEO were weighed and LiC10 _4, they were dissolved in deionized water, ultrasonic dispersion for 20 to 60 minutes, and the total concentration of PEO dubbed LiC10 ₄ 12.4 ~20.0 g/L mixed aqueous solution (for example, in some embodiments of the present invention, a mixed aqueous solution having a total concentration of PEO and LiC10 ₄ of 12.4 to 19.8 g/L); according to the mass ratio of LDHNS to PEO 0.01:1~0.55:1 ratio, the corresponding amount of LDHNS sol is added to the mixed solution of PEO and LiC10 ₄ , and the three mixed solutions are used in the internal cutting homogenizer. Disperse at 1000~4000 rpm for 20~60 minutes to make it fully mixed. The mixed solution prepared above is evaporated under reduced pressure to remove solvent water. When the solution is viscous, it is added dropwise to the mold. After drying at ~100 ° C to form a film, a composite solid electrolyte can be obtained.

The product structure was characterized by Xingji XRD-6000 X-ray powder diffractometer (XRD). The thermal stability of the product was characterized by HCT-2 microcomputer differential thermal balance in Beijing Hengjiu Scientific Instrument Factory. The composite film was sandwiched between two surfaces. Between the stainless steel substrates, the AM6e electrochemical workstation from ZAHNER ELEKTRIK, Germany, was used for AC impedance testing. Calculate the room temperature conductivity of the composite according to the formula σ = 1/R _b .d/S, where σ is the conductivity, the unit is S/cm, R _b is the resistance of the composite film, d is the thickness of the composite film, and S is the composite The area of the film. The Li/PEO electrolyte membrane/Li button battery was assembled, and the current-time (It) curve was recorded using a US Arbin MSTAT4+ type constant current charge and discharge meter. According to the formula ti. _n = I _f /Ii calculates the lithium ion migration number of the composite film, where t i _{∞ 1} is the number of lithium ion migration, Ii is the initial current, and If is the current at equilibrium. The results show that using the method of the present invention prepared by the inorganic / organic nano composite solid electrolyte may effectively reduce the crystallinity of the PEO and having good thermal stability, the conductive polymer is increased from room temperature electrical conductivity of PEO 10_ ⁸ S / cm to 10_ ^{At 6} S/cm, the number of lithium ion migrations increased from 0.142 to more than 0.20.

The effects and advantages of the present invention are as follows: The inorganic/organic nanocomposite solid electrolyte of the present invention has high room temperature conductivity and lithium ion migration number, and has good thermal stability, and can be used as a solid electrolyte material for a lithium ion battery. DRAWINGS

Fig. 1 is an XRD chart of a composite solid electrolyte membrane having a LDHNS (Mg/Al = 2) doping amount of 10% of the hydrotalcite nanosheets obtained in Example 1. Among them, the abscissa is the angle 2Θ, the unit is the degree (°); the ordinate is the diffraction intensity, and the unit is the absolute unit (a.u.).

2 is a TG-DTA graph of a composite solid electrolyte membrane having a hydrotalcite nanosheet LDHNS (Mg/Al = 2) doping amount of 10% obtained in Example 1. Where the abscissa is temperature, the unit is Celsius (°C); the left axis is the weight loss rate, the unit is the percentage (%); the ordinate is the difference heat, the unit It is microvolt (μν).

Fig. 3 is an alternating current impedance spectrum of a composite solid electrolyte membrane having a 10% doping amount of travertine nanosheets LDHNS (Mg/Al = 2) obtained in Example 1. Among them, the abscissa is the real part, the unit is kilo ohm (kQ); the ordinate is the imaginary part, the unit is kilo ohm Ω).

Fig. 4 is a time-current graph of the composite solid electrolyte membrane in which the hydrotalcite nanosheet LDHNS (Mg/Al = 2) doped in Example 1 was 10%. Where the abscissa is time, the unit is seconds (s); the ordinate is current, and the unit is microamperes (μΑ). detailed description

The technology and features of the present invention are described in detail below by way of specific embodiments, but these embodiments are not intended to limit the scope of the present invention. Example 1

The experimental water was a freshly distilled secondary deionized water containing C0 ₂ and the reaction was carried out under a N ₂ atmosphere. Weigh 10.24 g of Mg(N0 ₃ ) ₂ '6H ₂ 0 and 7.50 g of Α1(Ν0 ₃ ) ₃ ·9Η ₂ 0, dissolved in 120 mL of deionized water with C0 ₂ to form 0.5 mol/L. The mixed solution (molar ratio of Mg ²⁺ to Al ³⁺ is 2:1) was added dropwise to 80 mL of a 0.5 mol/L lactic acid (LA) solution (the molar ratio of LA to Mg ²⁺ was 1:1). . At the same time, 40 mL of 5 mol/L NaOH solution (5:1 molar ratio of NaOH to Mg ²⁺ ) was added dropwise to obtain a slurry. The pH of the slurry system was maintained during the dropwise addition, and the obtained slurry was in a closed container. After crystallization at 100 ° C for 10 hours, a lactic acid intercalated hydrotalcite can be obtained. The lactic acid intercalated hydrotalcite was washed with deionized water de C0 ₂ , and then centrifuged at 10,000 rpm for 5 minutes at high speed to remove the supernatant. The solid precipitate was washed with deionized water de C0 ₂ and then continued at a high speed. The above washing and high-speed centrifugation were repeated by centrifugation until the pH of the system was 7. The solid precipitate obtained by high-speed centrifugation was refluxed for 10 hours under boiling to obtain an LDHNS sol, and the concentration was adjusted to 5 g/L. The sol was applied to a frosted glass sheet for XRD analysis, and the XRD pattern showed that the layered structure disappeared, and it was considered that the LDHNS with a positive charge was obtained.

Weigh 1.0 g of PEO and 0.125 g of LiC10 _{4 respectively} (the mass ratio of PEO to LiC10 ₄ is 8:1) Dissolved in 80 mL of water and sonicated for 20 minutes. 20 mL of the above-prepared LDHNS sol with a concentration of 5 g/L (the mass ratio of LDHNS to PEO is 0.1:1) was poured into a mixed aqueous solution of PEO and LiC10 ₄ while using an internal-type homogenizer at 4000 rpm. Disperse for 30 minutes at a speed of /min, so that it is well mixed. The mixed solution prepared above is distilled off under reduced pressure to remove solvent water. When the solution is viscous, it is dropped into a polytetrafluoroethylene mold and dried at 80 ° C to form a film, thereby obtaining a composite material of the present invention. The thickness is 270 μπι.

The XRD spectrum of the composite material of the present invention is shown in Fig. 1. The characteristic diffraction peak intensity of the ΡΕΟ crystal structure is significantly reduced, indicating that the use of LDHNS as an inorganic filler can break the double helix structure of PEO, and effectively reduce the crystallinity of PEO. The TG-DTA curve of the composite material is shown in Fig. 2. As can be seen from the figure, the LDHNS-doped composite electrolyte membrane loses about 85% at 600 °C compared with pure PEO. The first weightless platform temperature increased from 210 ° C to 309 ° C for pure PEO. This indicates an increase in the thermal stability of the composite. At the same time, compared with pure PEO, the melting temperature of the composite decreased from 67.5 ° C to 61.0 ° C, further indicating that the crystallinity of PEO can be effectively reduced by doping LDHNS. A wafer having an area of 1.5 cm ^{2 was} cut out using the above-mentioned composite film having a thickness of 270 μm, and was sandwiched between two polished stainless steel sheets for AC impedance test. The AC impedance spectrum is shown in FIG. From the AC impedance spectrum, the composite film resistance R _b is 17.8 Q, and the room temperature conductivity of the composite is calculated by the formula o= l/R _b .d/S. The ratio of the room temperature conductivity is 1.Olxl- ⁶ S/cm, which is purer than PEO. The room temperature conductivity is increased by two orders of magnitude from 1.01 x ^{10 - 8} S/cm. The time-current curve of the composite film was recorded by assembling a button cell as shown in FIG. The initial current value Ii is read from the figure as 20.1 μΑ, and the steady-state current value If is 4.9 μΑ, by the formula ti. _n = I _f /Ii calculates the lithium ion migration number of the composite material to be 0.24. The above characterization results show that the composite has good thermal stability, high room temperature conductivity and lithium ion migration number, and can be used as a solid electrolyte material for lithium ion batteries. Example 2

The experimental water was a freshly distilled secondary deionized water containing C0 ₂ and the reaction was carried out under a N ₂ atmosphere. Weigh 2.97 g of Ζη(Ν0 ₃ ) ₂ ·6Η ₂ 0 and 1.875 g of Α1(Ν0 ₃ ) ₃ ·9Η ₂ 0 150 mL of deionized water with C0 ₂ is added to a mixed solution with a concentration of 0.1 mol/L (molar ratio of Zn ²⁺ to Al ³⁺ is 2:1), and added dropwise to a concentration of 50 ml of 0.4 mol/L. In lactic acid (LA) solution (LA to Zn ²⁺ molar ratio is 2:1). At the same time, 80 mL of 1.0 mol/L NaOH solution (8:1 molar ratio of NaOH to Zn ²⁺ ) was added dropwise to obtain a slurry. The slurry was stirred and maintained at pH = 12 during the dropwise addition, and the resulting slurry was in a closed container. After crystallization at °C for 4 hours, a lactic acid intercalated hydrotalcite can be obtained. The lactic acid intercalated hydrotalcite was washed with deionized water de C0 ₂ and then centrifuged at 8000 rpm for 10 minutes at high speed to remove the supernatant. The solid precipitate was washed with deionized water de C0 ₂ and then continued at high speed. The above washing and high-speed centrifugation were repeated by centrifugation until the pH of the system was 7.5. The solid precipitate obtained by high-speed centrifugation was refluxed for 8 hours under boiling to obtain an LDHNS sol, and the concentration was adjusted to 1 g/L.

1.0 g of PEO and 0.20 g of LiC10 ₄ (5:1 ratio of PEO to LiC10 ₄ ) were weighed and dissolved in 80 mL of water, and ultrasonically dispersed for 40 minutes. 100 mL of the LDHNS sol prepared above (the mass ratio of LDHNS to PEO is 0.1:1) was added to the mixed aqueous solution of PEO and LiC10 ₄ while dispersing at 1500 rpm for 30 minutes using an internal-type homogenizer. Make it mix well. The mixed solution prepared above was evaporated under reduced pressure to remove solvent water. When the solution was viscous, it was dropped into a polytetrafluoroethylene mold, and dried to form a film at ioo °c to obtain a composite film of the present example.

The composite film of this example was characterized as in Example 1. The XRD spectrum shows that the characteristic diffraction peak intensity of PEO crystals is significantly smaller, indicating that the addition of LDHNS effectively reduces the crystallinity of PEO. The room temperature conductivity of the composite film of this example was ll lxlO- ⁶ S/cm, and the lithium ion migration number was 0.26. Example 3

The experimental water was a freshly distilled secondary deionized water containing C0 ₂ and the reaction was carried out under a N ₂ atmosphere. Weigh 23.28 g of Ο)(Ν0 ₃ ) ₂ ·6Η ₂ 0 and 7.50 g of Α1(Ν0 ₃ ) ₃ ·9Η ₂ 0 dissolved in 100 mL of deionized water with C0 ₂ to form 1.0 mol/L The mixed solution (Co ²⁺ to Al ³⁺ molar ratio of 4:1) was added dropwise to 100 mL of a 4.80 mol/L lactic acid (LA) solution (LA and The molar ratio of Co ²⁺ is 6:1). At the same time, 80 mL of a 5 mol/L NaOH solution (5:1 molar ratio of NaOH to Co ²⁺ ) was added dropwise to obtain a slurry, and the pH of the slurry system was maintained while stirring during the dropwise addition. The resulting slurry was crystallized at 80 ° C for 16 hours in a closed vessel to obtain a lactic acid intercalated hydrotalcite. The lactic acid intercalated hydrotalcite was washed with deionized water de C0 ₂ , and then centrifuged at 10,000 rpm for 15 minutes at high speed to remove the supernatant liquid. The solid precipitate was washed with deionized water de C0 ₂ and then continued at a high speed. The above washing and high-speed centrifugation were repeated by centrifugation until the pH of the system was 7. The solid precipitate obtained by high-speed centrifugation was refluxed for 10 hours under boiling to obtain an LDHNS sol, and the concentration was adjusted to 2 g/L.

Weigh 100 g of PEO and 0.1 g of LiC10 ₄ (10:1 ratio of PEO to LiC10 ₄ ), dissolve in 55 mL of water, and disperse for 40 minutes. 25 mL of the LDHNS sol prepared above (the mass ratio of LDHNS to PEO was 0.05:1) was added to the mixed aqueous solution of PEO and LiC10 ₄ while dispersing at 4000 rpm for 60 minutes using an internal-type homogenizer. Make it mix well. The mixed solution prepared above was evaporated under reduced pressure to remove solvent water. When the solution was viscous, it was added dropwise to a polytetrafluoroethylene mold, and dried at 60 ° C to form a film of the composite material of this example.

The composite film of this example was characterized as in Example 1. The XRD spectrum shows that the characteristic diffraction peak intensity of PEO crystals is significantly smaller, indicating that the addition of LDHNS effectively reduces the crystallinity of PEO. The room temperature conductivity of the composite film of this example was 1.05 x ^{10 -6} S/cm, and the lithium ion migration number was 0.24. Example 4

The experimental water was a freshly distilled secondary deionized water containing C0 ₂ and the reaction was carried out under a N ₂ atmosphere. Weigh 40.74 g of Co(N0 ₃ ) ₂ '6H ₂ 0 and 14.14 g of Fe(N0 ₃ ) ₃ '9H ₂ 0 in 100 mL of deionized water with C0 ₂ to prepare a concentration of 1.75 mol/L. The mixed solution (4:1 molar ratio of Co ²⁺ to Fe ³⁺ ) was added dropwise to 100 mL of a 11.2 mol/L lactic acid (LA) solution (the molar ratio of LA to Co ²⁺ was 8: 1). At the same time, 175 mL of NaOH solution with a concentration of 8.0 mol/L (a molar ratio of NaOH to Co ²⁺ of 10:1) was added dropwise to obtain a slurry, which was stirred and maintained during the dropwise addition. The pH of the liquid system was 8. The obtained slurry was crystallized at 60 ° C for 20 hours in a closed vessel to obtain a lactic acid intercalated hydrotalcite. The lactic acid intercalated hydrotalcite was washed with deionized water de C0 ₂ and then centrifuged at 8000 rpm for 20 minutes at high speed to remove the supernatant. The solid precipitate was washed with deionized water de C0 ₂ and then continued at high speed. The above washing and high-speed centrifugation were repeated by centrifugation until the pH of the system was 7. The solid precipitate obtained by high-speed centrifugation was refluxed for 10 hours under boiling to obtain an LDHNS sol, and the concentration was adjusted to 8 g/L.

Weigh 1.0 g of PEO and 0.083 g of LiC10 ₄ (the mass ratio of PEO to LiC10 ₄ is 12:1). Dissolve in 60 mL of water and ultrasonically disperse for 40 minutes. 37.5 mL of the LDHNS sol prepared above (the mass ratio of LDHNS to PEO was 0.30:1) was added to the mixed aqueous solution of PEO and LiC10 ₄ while dispersing at 3000 rpm for 40 minutes using an internal-type homogenizer. Make it mix well. The mixed solution prepared above was evaporated under reduced pressure to remove solvent water. When the solution was viscous, it was dropped into a polytetrafluoroethylene mold and dried at 80 ° C to form a film of the composite material of this example.

The composite film of this example was characterized as in Example 1. The XRD spectrum shows that the characteristic diffraction peak intensity of PEO crystals is significantly smaller, indicating that the addition of LDHNS effectively reduces the crystallinity of PEO. Example room temperature electrical conductivity composite membrane according to the present embodiment is 1.22x lO- ⁶ S / cm, the lithium ion transport number of 0.20. Example 5

The experimental water was a freshly distilled secondary deionized water containing C0 ₂ and the reaction was carried out under a N ₂ atmosphere. 46.53 g of Ni(N0 ₃ ) ₂ '6H ₂ 0 and 21.54 g of Fe(N0 ₃ ) ₃ '9H ₂ 0 were weighed into 100 mL of a mixed solution of 2.13 mol/L (Ni ²⁺ and Fe ^{3 ).} The molar ratio of ⁺ is 3:1), and it is added dropwise to 100 mL of a 16 mol/L lactic acid (LA) solution (the molar ratio of LA to Ni ²⁺ is 10:1). At the same time, 128 mL of a 10 mol/L NaOH solution (8:1 molar ratio of NaOH to Ni ²⁺ ) was added dropwise to obtain a slurry, and the pH of the slurry system was maintained at a stirring rate during the dropwise addition. The resulting slurry was crystallized at 100 ° C for 24 hours in a closed vessel to obtain a lactic acid intercalated hydrotalcite. The lactic acid intercalated hydrotalcite was washed with deionized water de C0 ₂ and then centrifuged at high speed for 10 minutes at 10,000 rpm. The supernatant was removed, and the solid precipitate was washed with deco ₂ deionized water and then subjected to high-speed centrifugation. The above washing and high-speed centrifugation were repeated until the pH of the system was 7.5. The solid precipitate obtained by high-speed centrifugation was refluxed for 10 hours under boiling to obtain an LDHNS sol, and the concentration was adjusted to 4 g/L.

Weigh 1.0 g of PEO and 0.125 g of LiC10 ₄ (the mass ratio of PEO to LiC10 ₄ is 8:1). Dissolve in 60 mL of water and ultrasonically disperse for 45 minutes. 100 mL of the LDHNS sol prepared above (the mass ratio of LDHNS to PEO is 0.4:1) was added to a mixed aqueous solution of PEO and LiC10 ₄ while dispersing at an internal cutting type homogenizer at a speed of 2500 rpm for 60 minutes. Make it mix well. The mixed solution prepared above was evaporated under reduced pressure to remove solvent water. When the solution was viscous, it was added dropwise to a polytetrafluoroethylene mold, and dried at 90 ° C to form a film of the composite material of this example.

The composite film of this example was characterized as in Example 1. The XRD spectrum shows that the characteristic diffraction peak intensity of PEO crystals is significantly smaller, indicating that the addition of LDHNS effectively reduces the crystallinity of PEO. The room temperature conductivity of the composite film of this example was 1.02 x ^{10 -6} S/cm, and the lithium ion migration number was 0.20.

Claims

Claim

An inorganic/organic nanocomposite solid electrolyte characterized in that the solid electrolyte is composed of polyoxyethylene PEO, lithium perchlorate LiC10 ₄ and hydrotalcite nanosheet LDHNS, and its chemical composition is PEO/LiC10. ₄ / LDHNS, the mass fraction of each component is 54% ~ 91%, 6% ~ 16% and 1% ~ 30%.

The inorganic/organic nanocomposite solid electrolyte according to claim 1, wherein the chemical composition of the hydrotalcite nanosheet LDHNS is [Μ ²⁺ _μχ Μ ³⁺ _χ (ΟΗ) ₂ ] ^{χ +} , Μ ²⁺ is any one of divalent metal ions Mg ²⁺ , Zn ²⁺ , Ni ²⁺ , Fe ²⁺ , Co ²⁺ ; M ³⁺ is a trivalent metal ion Al ³⁺ , Cr ³⁺ , Fe ^{3 +} , V ³⁺ , Co ³⁺ , Ga ³⁺ , Ti ³⁺ ; x + is the positive charge of the hydrotalcite nanosheet LDHNS; X is the mole fraction of the trivalent metal ion M ³⁺ The value range is 0.2 ^ X 0.4.

The inorganic/organic nanocomposite solid electrolyte according to claim 1, wherein M ²⁺ is a divalent metal ion Mg ²⁺ .

The inorganic/organic nanocomposite solid electrolyte according to claim 1 or 3, wherein M ³⁺ is a trivalent metal ion Al ³⁺ .

A method for producing an inorganic/organic nanocomposite solid electrolyte according to claim 1, wherein the polyoxyethylene PEO, the lithium perchlorate LiC10 ₄ and the hydrotalcite nanosheet LDHNS are in a certain mass ratio in an aqueous solution. The mixture was uniformly mixed, and then the solvent was evaporated to obtain a PEO/LiC10 ₄ /LDHNS composite solid electrolyte.

6. The method of claim 5, wherein the method comprises the steps of:

A. Preparation of hydrotalcite nanosheets LDHNS sol

^Dissolving a soluble salt of M ^{2+ and} a soluble salt of M ^{3+ in} a molar ratio of M ²⁺ /M ³⁺ of 2:1 to 4:1 in deionized water de C0 ₂ to form a mixed salt solution, and controlling metal ion (M ²⁺ + M ³⁺⁾ total concentration of 0.10 ~ 2.4 mol / L; NaOH molar ratio of the M ²⁺ is from 5: 1 to 10: 1 ratio of NaOH dissolved C0 ₂ to release the Ionic water is formulated into an alkali solution having a concentration of 0.50 to 10.0 mol/L; The molar amount is 1 to 10 times the molar amount of M ²⁺ . The lactic acid is dissolved in deionized water de C0 ₂ to prepare a lactic acid aqueous solution having a concentration of 0.20-16 mol/L;

The mixed salt solution and the alkali solution are simultaneously added dropwise to the aqueous solution of lactic acid under the protection of N ₂ to obtain a slurry. The pH of the system is maintained at 8 to 12 during the dropwise addition, and then the slurry is protected under N ₂ at 40 to 100. Crystallization for 2 to 24 hours under °C conditions, to obtain hydrotalcite intercalated hydrotalcite;

The lactic acid intercalated hydrotalcite is washed with deionized water de C0 ₂ and then centrifuged at 8000-10000 rpm for 5-20 minutes at high speed to remove the supernatant. The solid precipitate is deionized water with C0 ₂ . After washing, the high-speed centrifugation is continued, and the above washing and high-speed centrifugation are repeated until the pH of the system is 7 to 7.5. The solid precipitate obtained by high-speed centrifugation is refluxed for 8 to 10 hours under boiling to obtain an LDHNS sol, and the concentration thereof is adjusted. 1~10 g/L spare;

B. Preparation of inorganic/organic nanocomposite solid electrolyte

According to the ratio of PEO to LiC10 _{4, the} ratio of 4:1 to 12:1 is weighed PEO and LiC10 _{4 respectively} , dissolved in deionized water, and mixed into a mixed aqueous solution of PEO and LiC10 _{4 with a} total concentration of 12.4-20.0 g/L. Ultrasonic dispersion for 20~60 minutes;

According to the ratio of LDHNS to PEO, the ratio is 0.01:1~0.55:1, and the corresponding amount is measured.

The LDHNS sol is added to the above mixed aqueous solution of PEO and LiC10 ₄ , and the three mixed solutions are dispersed by using an internal-type homogenizer at a rotation speed of 1000 to 4000 rpm for 20 to 60 minutes to be uniformly mixed; The mixed solution is evaporated under reduced pressure to evaporate the solvent water. When the solution is viscous, it is added dropwise to a mold, and dried at 60 to 100 ° C to form a composite solid electrolyte.

7. The method according to claim 6, wherein the soluble salt of M ²⁺ described in step A is nitrate of Mg ²⁺ , Zn ²⁺ , Ni ²⁺ , Fe ²⁺ , Co ²⁺ . Any of the soluble salts of M ³⁺ is any of the nitrates of Al ³⁺ , Cr ³⁺ , Fe ³⁺ , V ³⁺ , Co ³⁺ , Ga ³⁺ , and Ti ³⁺ .

8. The method according to claim 6, wherein the soluble salt of M ²⁺ described in step A is Mg(N0 ₃ ) ₂ .

9. A method according to claim 6 or 8, wherein the soluble salt of M3 ⁺ described in step A is A1(N0 ₃ ) ₃ .

10. The method of claim 6, characterized in that the C0 ₂ removal of the deionized water used in Step A is open deionized water boiled for 5 to 10 minutes, and then naturally cooled to under static conditions Obtained after room temperature.