CN1640935A - Full-solid composite polymer electrolyte containing cellular material and its preparation method - Google Patents

Abstract

The invention discloses an all-solid composite polymer electrolyte containing a mesoporous material and a preparation method thereof. The electrolyte is composed of polyethylene oxide, lithium salt and a mesoporous material, and the mesoporous material accounts for 1 to 30 wt.% of the polyethylene oxide; Dissolve lithium salt and mesoporous material with acetonitrile; add polyethylene oxide to form a uniform solution; cast the uniform solution into a polytetrafluoroethylene mold, evaporate the solvent, and dry in a vacuum oven to obtain an all-solid state containing mesoporous material composite polymer electrolyte. The present invention prepares an all-solid-state composite polymer with high ion conductivity, high lithium ion migration number, good electrode interface stability and electrochemical stability by incorporating mesoporous materials into polyethylene oxide/lithium salts matter electrolyte. The prepared all-solid composite polymer electrolyte containing the mesoporous material can be applied to the field of lithium-ion secondary batteries.

Description

All-solid composite polymer electrolyte containing mesoporous material and preparation method thereof

technical field

The invention relates to a polymer electrolyte and a preparation method thereof, in particular to an all-solid composite polymer electrolyte containing mesoporous materials for lithium-ion secondary batteries and a preparation method thereof.

Background technique

Since British Wright et al. (D.E.Fenton, J.M.Parker, P.V.Wright, Polymer, 1973, 14, 589) discovered in 1973 that the complexes of polyethylene oxide (PEO) and alkali metal salts have ion conductivity, polyethylene oxide -Lithium salt (PEO-LiX) system polymer electrolyte has attracted widespread attention because it may replace the liquid electrolyte in traditional lithium-ion secondary batteries and become the electrolyte material in all-solid-state lithium-ion secondary batteries (J.M.Tarascon, M.Armand , Nature, 2001, 414, 359).

After adding inorganic fillers to the traditional PEO-LiX polymer electrolyte system to obtain a composite polymer electrolyte, its ionic conductivity, electrode interface stability and mechanical properties can be greatly improved (J.Zhou, P.Fedkiw, Solid State Ionics, 2004, 166, 275). Incorporated inorganic fillers are mainly divided into fillers with layered structure (L.Z.Fan, C.W.Nan, M.Li, Chem.Phys.Lett., 2003, 369, 698) and nano-ceramic oxide fillers (F.Croce, R .Curini, A.Martinelli, L.Persi, F.Ronci, B.Scrosati, J.Phys.Chem.B, 1999, 103, 10632) two categories.

Contents of the invention

The object of the present invention is to provide an all-solid-state composite polymer electrolyte containing mesoporous materials, which has high ion conductivity, high lithium ion transfer number, good electrode interface stability and electrochemical stability, and a preparation method thereof.

The composition of the all-solid composite polymer electrolyte containing mesoporous material of the present invention is polyoxyethylene, lithium salt and mesoporous material; Its proportioning is: the O/Li molar ratio of polyoxyethylene and lithium salt is 8～ 24. The mesoporous material accounts for 1 to 30 wt.% of polyethylene oxide; the molecular weight of polyethylene oxide is 2×10 ⁵ to 1×10 ⁶ ; the lithium salt is LiClO ₄ , LiBF ₄ , LiPF ₆ or LiCF ₃ SO ₃ ; The mesoporous material is SBA-15, MCM-41 or HMS, wherein SBA-15 can also be SBA-15 containing template agent.

The preparation method of a kind of all-solid composite polymer electrolyte containing mesoporous material of the present invention is as follows:

In an acetonitrile solvent equivalent to 15 to 25 times the mass of polyethylene oxide, add a lithium salt with a molar ratio of 8 to 24 to polyethylene oxide O/Li and a mesoporous material accounting for 1 to 30 wt.% of polyethylene oxide, and ultrasonically disperse to homogeneous; add polyethylene oxide to the above solution, and stir until a uniform viscous solution; cast the above viscous solution into a polytetrafluoroethylene mold, evaporate the solvent, and then dry it in a vacuum oven at 50°C to obtain a mesoporous material containing All-solid composite polymer electrolyte;

The molecular weight of polyethylene oxide is 2×10 ⁵ to 1×10 ⁶ ; the lithium salt is LiClO ₄ , LiBF ₄ , LiPF ₆ or LiCF ₃ SO ₃ ; the mesoporous material is SBA-15, MCM-41 or HMS, where SBA -15 can also be SBA-15 containing a templating agent.

The present invention is prepared by mixing mesoporous materials (such as SBA-15, MCM-41, HMS), especially mesoporous materials containing templates (SBA-15 containing templates) into polyethylene oxide/lithium salts An all-solid-state composite polymer electrolyte containing mesoporous materials with high ionic conductivity, high lithium ion transfer number, good electrode interface stability and electrochemical stability has been developed. The prepared all-solid-state composite polymer electrolyte can be applied to the field of lithium-ion secondary batteries. The room temperature ion conductivity of the all-solid composite polymer electrolyte containing mesoporous materials can reach 2.4×10 ^-5 S·cm ^-1 ; the lithium ion migration number can reach more than 0.5; the decomposition voltage exceeds 4.5V.

Description of drawings

Figure 1 shows the sample PEO ₁₂ -LiClO ₄ of Comparative Example 1, the sample PEO ₁₂ -LiClO ₄ /10%SBA-15 of Example 1, the sample PEO ₁₂ -LiClO ₄ /10%P123@SBA-15 of Example 2, and the sample of Example 3 The ion conductivity of the sample PEO ₁₂ -LiClO ₄ /10%MCM-41 and the example 4 sample PEO ₁₂ -LiClO ₄ /10%HMS change with temperature.

Figure 2 shows the sample PEO ₁₂ -LiClO ₄ of Comparative Example 1, the sample PEO ₁₂ -LiClO ₄ /10%SBA-15 of Example 1, the sample PEO ₁₂ -LiClO ₄ /10%P123@SBA-15 of Example 2, and the sample of Example 3 Lithium ion migration numbers of the sample PEO ₁₂ -LiClO ₄ /10%MCM-41 and the example 4 sample PEO ₁₂ -LiClO ₄ /10%HMS.

Fig. 3 is a diagram showing the variation of the ion conductivity of the sample PEO ₁₂ -LiClO ₄ /X%SBA-15 in Example 1 with temperature.

Fig. 4 is a time-dependent diagram of the interfacial resistance between the sample PEO ₁₂ -LiClO ₄ /X%SBA-15 and the lithium metal electrode in Example 1.

Fig. 5 is a diagram showing the variation of the ion conductivity of the sample PEO ₁₂ -LiClO ₄ /X%P123@SBA-15 with temperature in Example 2.

Fig. 6 is a diagram showing the variation of the lithium ion migration number of the sample PEO ₁₂ -LiClO ₄ /X%P123@SBA-15 with the content of P123@SBA-15 in Example 2.

Fig. 7 is the potential scanning curve of the sample PEO ₁₂ -LiClO ₄ /X%P123@SBA-15 in Example 2.

Specific implementation method

The following examples are to further illustrate the present invention, but not to limit the scope of the present invention.

Mesoporous material SBA-15 used in the present invention and SBA-15 reference literature (D.Y.Zhao, J.L.Feng, Q.S.Huo, N.Melosh, G.H.Fredrickson, B.F.Chmelka, G.D.Stucky, Science, 1998,279,548) containing template agent Preparation, mesoporous material MCM-41 refers to literature (M.Broyer, S.Valange, J.P.Bellat, O.Bertrand, G.Weber, Z.Gabelica, Langmuir, 2002, 18, 5083) preparation, mesoporous material HMS refers to literature (B. L. Newalkar, N. V. Choudary, U. T. Turaga, R. P. Vijayalakshmi, P. Kumar, S. Komarneni, T. S. G. Bhat, Micropor. Mesopor. Mat., 2003, 65, 267).

Example 1 PEO-LiClO ₄ /SBA-15

Take 0.101g LiClO ₄ and 0.005~0.15g SBA-15 and dissolve them in 12mL of acetonitrile, ultrasonically disperse for 15min and then stir for 2h, then add 0.5g of PEO (molecular weight: 1×10 ⁶ ) under strong stirring condition with O/Li molar ratio of 12 After stirring at room temperature for 24 hours, a uniform and transparent viscous solution was obtained. The solution was poured into a polytetrafluoroethylene mold and placed in a self-built atmospheric pressure purging device, and purged with dry air at a flow rate of 10L min ^-1 for 48 hours. After the acetonitrile solvent was basically volatilized, it was dried in vacuum at 50°C for 24 hours to remove a small amount of residual solvent. The thickness of the finally obtained PEO ₁₂ -LiClO ₄ /X%SBA-15 translucent self-supporting film is about 100-200 μm. Then the prepared samples were tested for ionic conductivity (Fig. 1, Fig. 3), lithium ion migration number (Fig. 2), and electrode interface stability (Fig. 4).

Example 2 PEO-LiClO ₄ /P123@SBA-15

Take 0.101g LiClO ₄ and 0.015～0.1g P123@SBA-15 and dissolve them in 12mL acetonitrile, ultrasonically disperse for 15min and then stir for 2h, then add 0.5g PEO (molecular weight 1×10 ⁶ ), the preparation process is with embodiment 1. The thickness of the finally obtained PEO ₁₂ -LiClO ₄ /X%P123@SBA-15 translucent self-supporting film is about 100-200 μm. Then the prepared samples were tested for ionic conductivity (Fig. 1, Fig. 5), lithium ion migration number (Fig. 2, Fig. 6) and electrochemical stability window (Fig. 7).

Example 3 PEO-LiClO ₄ /MCM-41

Take 0.101g LiClO ₄ and 0.05g MCM-41 and dissolve them in 12mL of acetonitrile, ultrasonically disperse them for 15min and then stir for 2h, then add 0.5g of PEO (molecular weight of 1×10 ⁶ ) under strong stirring conditions according to the O/Li molar ratio of 12 to prepare Process is with embodiment 1. The thickness of the finally obtained PEO ₁₂ -LiClO ₄ /10%MCM-41 translucent self-supporting film is about 150 μm. Then the prepared samples were tested for ionic conductivity (Fig. 1) and lithium ion migration number (Fig. 2).

Example 4 PEO-LiClO ₄ /HMS

Dissolve 0.101g LiClO ₄ and 0.05g HMS in 12mL of acetonitrile, ultrasonically disperse for 15min and then stir for 2h, then add 0.5g of PEO (molecular weight: 1×10 ⁶ ) under strong stirring conditions with the O/Li molar ratio of 12, the preparation process is the same as Example 1. The thickness of the finally obtained PEO ₁₂ -LiClO ₄ /10%HMS translucent self-supporting film is about 150 μm. Then the prepared samples were tested for ionic conductivity (Fig. 1) and lithium ion migration number (Fig. 2).

Comparative example 1 PEO-LiClO ₄

0.101g LiClO ₄ was completely dissolved in 12mL of acetonitrile, and 0.5g of PEO (molecular weight of 1×10 ⁶ ) was added under strong stirring conditions with an O/Li molar ratio of 12. The preparation process was the same as in Example 1. The thickness of the finally obtained PEO ₁₂ -LiClO ₄ translucent self-supporting film is about 150 μm. Then the prepared samples were tested for ionic conductivity (Fig. 1) and lithium ion migration number (Fig. 2).

Claims (2)

1. An all-solid composite polymer electrolyte containing a mesoporous material, characterized in that it is composed of polyethylene oxide, lithium salt and mesoporous material; its proportioning ratio is: the O/Li molar ratio of polyethylene oxide and lithium salt 8~24, the mesoporous material accounts for 1~30wt.% of polyethylene oxide; the molecular weight of polyethylene oxide is 2×10 ⁵ ～1×10 ⁶ ; the lithium salt is LiClO ₄ , LiBF ₄ , LiPF ₆ or LiCF ₃ SO ₃ ; the mesoporous material is SBA-15, MCM-41 or HMS, wherein SBA-15 can also be SBA-15 containing a template. 2. A method for preparing the all-solid composite polymer electrolyte containing mesoporous materials as claimed in claim 1, characterized in that the method is: In an acetonitrile solvent equivalent to 15 to 25 times the mass of polyethylene oxide, add a lithium salt with a molar ratio of 8 to 24 to polyethylene oxide O/Li and a mesoporous material accounting for 1 to 30 wt.% of polyethylene oxide, and ultrasonically disperse to homogeneous; add polyethylene oxide to the above solution, and stir until a uniform viscous solution; cast the above viscous solution into a polytetrafluoroethylene mold, evaporate the solvent, and then dry it in a vacuum oven at 50°C to obtain a mesoporous material containing All-solid composite polymer electrolyte; Among them, the molecular weight of polyethylene oxide is 2×10 ⁵ to 1×10 ⁶ ; the lithium salt is LiClO ₄ , LiBF ₄ , LiPF ₆ or LiCF ₃ SO ₃ ; the mesoporous material is SBA-15, MCM-41 or HMS, where SBA -15 can also be SBA-15 containing a templating agent.

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