TiO2-coated graphite double-ion battery composite positive electrode material and preparation method thereof

Abstract

The invention provides a preparation method of a TiO2-coated graphite double-ion battery composite positive electrode material. The method comprises the following steps: S1, by taking tetrabutyl titanate as a TiO2 source, uniformly mixing the tetrabutyl titanate with graphite powder, and putting the mixture into absolute ethyl alcohol to obtain a solid-liquid mixture; S2, continuously stirring thesolid-liquid mixture in a magnetic stirrer of a water bath kettle until absolute ethyl alcohol is completely evaporated to obtain a sample; and S3, heating the sample in an inert protective atmosphere, and carrying out heat preservation to obtain the TiO2-coated graphite double-ion battery composite positive electrode material. The TiO2-coated graphite double-ion battery composite positive electrode material provided by the invention is relatively good in cycle performance.

Description

Technical field

[0001] The invention relates to the technical field of energy storage and conversion materials, in particular to a coated TiO 2 Graphite dual-ion battery composite positive electrode material and preparation method thereof.

Background technique

[0002] The theoretical specific capacity of the embedded anion of the graphite material used in the positive electrode of the dual-ion battery is 120mAhg -1 , but the intercalation of anions would result in a volume expansion of about 130%. At the same time, the working voltage of about 5V inevitably leads to the decomposition of the electrolyte, so the actual specific cycle capacity of the graphite cathode is smaller than the theoretical cycle capacity, and the cycle performance is poor, making it difficult to be practical.

[0003] In the related art, in order to solve the above problems, currently, the cycle stability of the dual-ion battery is generally improved by adding high-voltage resistant additives to...

Examples

preparation example Construction

[0031] see figure 1 , the present invention provides the present invention provides a coated TiO 2 The preparation method of graphite double-ion battery composite cathode material comprises the steps:

[0032] S1: Using tetrabutyl titanate as TiO 2 source, mix the tetrabutyl titanate and graphite powder evenly, and put them into absolute ethanol to obtain a solid-liquid mixture;

[0033] S2: Stir the solid-liquid mixture continuously in a water bath with a magnetic stirrer until the absolute ethanol is completely evaporated to obtain a sample;

[0034] S3: The sample is heated and kept warm under an inert protective atmosphere to obtain a coated TiO 2 Graphite composite cathode material for dual-ion batteries.

[0035] Preferably, the mass ratio of tetrabutyl titanate to graphite powder is (0.05-0.15):1.

[0036] Preferably, the temperature of the water bath in the step S2 is 40-70°C.

[0037] Preferably, the heating temperature in the step S4 is 400°C-600°C, and the hol...

Embodiment 1

[0040] Mix tetrabutyl titanate and graphite powder according to the mass ratio of 0.15:1 and put them into an appropriate volume of absolute ethanol, place it in a 60°C water bath and continue magnetic stirring until the absolute ethanol is completely evaporated; the collected The sample was carbonized at 600°C for 3 hours in an argon atmosphere to obtain coated TiO 2 Graphite composite cathode material for dual-ion batteries.

[0041] Figure 2(a) shows the coated TiO 2 Composite cathode materials for graphite dual-ion batteries and uncoated TiO 2 The X-ray diffraction spectrum (XRD) contrast figure of the graphite double-ion battery cathode material of the present invention, wherein graph I is coated TiO 2 The X-ray diffraction spectrum (XRD) figure of the graphite dual-ion battery composite positive electrode material; Curve II is uncoated TiO 2 The X-ray diffraction spectrum (XRD) pattern of graphite dual-ion battery cathode material. Uncoated TiO 2 The graphite dual-i...

Embodiment 2

[0047] Mix tetrabutyl titanate and graphite powder according to the mass ratio of 0.05:1 and put them into an appropriate volume of absolute ethanol, place it in a 40°C water bath and continue magnetic stirring until the absolute ethanol evaporates; collect the obtained The sample was carbonized at 400°C for 6 hours in an argon atmosphere to obtain coated TiO 2 Graphite composite cathode material for dual-ion batteries.

[0048] Figure 3(a) is the coated TiO 2 SEM topography of graphite dual-ion battery composite cathode material, TiO 2 The nanoparticles are uniformly coated on the graphite surface. Figure 3(b) shows the coated TiO 2 The cycle performance diagram of graphite dual-ion battery composite positive electrode material at 2C current density, where curve I is coated TiO 2 The Coulombic efficiency curve of graphite dual-ion battery composite positive electrode material; Curve II is coated TiO 2 The charging capacity curve of graphite dual-ion battery composite cat...

Technical field

[0001] The invention relates to the technical field of energy storage and conversion materials, in particular to a coated TiO 2 Graphite dual-ion battery composite positive electrode material and preparation method thereof.

Background technique

[0002] The theoretical specific capacity of the embedded anion of the graphite material used in the positive electrode of the dual-ion battery is 120mAhg -1 , but the intercalation of anions would result in a volume expansion of about 130%. At the same time, the working voltage of about 5V inevitably leads to the decomposition of the electrolyte, so the actual specific cycle capacity of the graphite cathode is smaller than the theoretical cycle capacity, and the cycle performance is poor, making it difficult to be practical.

[0003] In the related art, in order to solve the above problems, currently, the cycle stability of the dual-ion battery is generally improved by adding high-voltage resistant additives to...

Examples

preparation example Construction

[0031] see figure 1 , the present invention provides the present invention provides a coated TiO 2 The preparation method of graphite double-ion battery composite cathode material comprises the steps:

[0032] S1: Using tetrabutyl titanate as TiO 2 source, mix the tetrabutyl titanate and graphite powder evenly, and put them into absolute ethanol to obtain a solid-liquid mixture;

[0033] S2: Stir the solid-liquid mixture continuously in a water bath with a magnetic stirrer until the absolute ethanol is completely evaporated to obtain a sample;

[0034] S3: The sample is heated and kept warm under an inert protective atmosphere to obtain a coated TiO 2 Graphite composite cathode material for dual-ion batteries.

[0035] Preferably, the mass ratio of tetrabutyl titanate to graphite powder is (0.05-0.15):1.

[0036] Preferably, the temperature of the water bath in the step S2 is 40-70°C.

[0037] Preferably, the heating temperature in the step S4 is 400°C-600°C, and the hol...

Embodiment 1

[0040] Mix tetrabutyl titanate and graphite powder according to the mass ratio of 0.15:1 and put them into an appropriate volume of absolute ethanol, place it in a 60°C water bath and continue magnetic stirring until the absolute ethanol is completely evaporated; the collected The sample was carbonized at 600°C for 3 hours in an argon atmosphere to obtain coated TiO 2 Graphite composite cathode material for dual-ion batteries.

[0041] Figure 2(a) shows the coated TiO 2 Composite cathode materials for graphite dual-ion batteries and uncoated TiO 2 The X-ray diffraction spectrum (XRD) contrast figure of the graphite double-ion battery cathode material of the present invention, wherein graph I is coated TiO 2 The X-ray diffraction spectrum (XRD) figure of the graphite dual-ion battery composite positive electrode material; Curve II is uncoated TiO 2 The X-ray diffraction spectrum (XRD) pattern of graphite dual-ion battery cathode material. Uncoated TiO 2 The graphite dual-i...

Embodiment 2

[0047] Mix tetrabutyl titanate and graphite powder according to the mass ratio of 0.05:1 and put them into an appropriate volume of absolute ethanol, place it in a 40°C water bath and continue magnetic stirring until the absolute ethanol evaporates; collect the obtained The sample was carbonized at 400°C for 6 hours in an argon atmosphere to obtain coated TiO 2 Graphite composite cathode material for dual-ion batteries.

[0048] Figure 3(a) is the coated TiO 2 SEM topography of graphite dual-ion battery composite cathode material, TiO 2 The nanoparticles are uniformly coated on the graphite surface. Figure 3(b) shows the coated TiO 2 The cycle performance diagram of graphite dual-ion battery composite positive electrode material at 2C current density, where curve I is coated TiO 2 The Coulombic efficiency curve of graphite dual-ion battery composite positive electrode material; Curve II is coated TiO 2 The charging capacity curve of graphite dual-ion battery composite cat...

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