A method for preparing vanadium trioxide / carbon supercapacitor electrode material

Abstract

A method for preparing vanadium trioxide / carbon supercapacitor electrode material belongs to the field of electrochemical energy storage, using vanadium acetylacetonate and glucose as raw materials, and preparing V 2 O 3 / C composite material, which is used as the electrode of supercapacitor with Na 2 SO 4 The aqueous solution is used as the electrolyte to assemble into a symmetrical aqueous supercapacitor. The raw material price of the invention is cheap and the preparation process is simple; V 2 O 3 The hollow nanospheres not only have a wide voltage window of ‑1.1~1.3 V (vs. Ag / AgCl), but also have a specific capacitance of 708.6 F g ‑1 ; V 2 O 3 / C hollow nanospheres as electrodes, Na 2 SO 4 The aqueous solution is used as the electrolyte, and the prepared symmetric supercapacitor has an operating voltage of up to 2.4 V and an ultra-high energy density of 96.8 W h kg ‑1 And excellent cycle stability.

Description

Technical Field

[0001] The invention belongs to the field of electrochemical energy storage and relates to a method for preparing a supercapacitor electrode material. Background Art

[0002] As a new type of energy storage device, supercapacitors have attracted much attention due to their much higher power density, fast charge and discharge capabilities, extremely long life, wide temperature range and environmental friendliness compared to batteries. However, their energy density is much lower than that of batteries, which greatly limits their application in various fields. Therefore, how to improve their energy density by designing efficient electrode materials has become an urgent problem to be solved at this stage.

[0003] The electrodes of supercapacitors are divided into positive and negative electrodes. At present, most research work is focused on how to prepare pseudocapacitive positive electrode materials with high specific capacitance. However, when applied to supercapacitors, their high specific capacitance cannot be effectively exerted, and the voltage range of the device is narrow. According to the energy density formula E = 1 / 2 CV 2 (its energy density (E) is proportional to its specific capacity (C) and working potential window (V)), the energy density of the prepared supercapacitor is still low. The main reason is that most of the current pseudocapacitor positive electrode materials have a narrow voltage range, and their extremely high specific capacitance is difficult to effectively match with the low specific capacitance carbon-based negative electrode materials, resulting in difficulty in improving the energy density of the device. Therefore, developing an electrode material that can be used as both the positive and negative electrodes and can be well matched can overcome this problem. Vanadium oxide has a higher voltage window and higher specific capacitance, and is a very promising high-voltage supercapacitor electrode material. Vanadium trioxide (V 2 O 3 ) has good intrinsic conductivity, which is conducive to the transmission and transfer of electrons, further expanding the possibility of vanadium oxide materials as high-voltage supercapacitors. However, how to prepare V with high working voltage and high specific capacitance? 2 O 3 The materials remain challenging. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing vanadium trioxide / carbon as a supercapacitor electrode material. 2 O 3 / C) hollow nanospheres as positive and negative electrodes are assembled into symmetrical aqueous supercapacitors with an operating voltage of up to 2.4 V. At the same time, it has the characteristics of high energy density, power density, excellent cycle stability and safety, providing an effective method for the design and preparation of high energy density supercapacitors.

[0005] The present invention is achieved through the following technical solutions.

[0006] The present invention discloses a method for preparing a supercapacitor electrode material vanadium trioxide / carbon, which uses glucose and vanadium acetylacetonate as raw materials, and prepares the electrode material by a hydrothermal method and subsequent heat treatment. 2 SO 4 Aqueous solution was used as the electrolyte to prepare symmetrical supercapacitors.

[0007] The method for preparing vanadium trioxide / carbon, a supercapacitor electrode material, according to the present invention, comprises the following steps.

[0008] (1) Add glucose to a mixed solution of deionized water and isopropanol in a volume ratio of 4:1 at a ratio of 40-60 / 5 (g / L) and stir until dissolved.

[0009] (2) Weigh vanadyl acetylacetonate in a mass ratio of 1:8-10 to glucose, add vanadyl acetylacetonate to the glucose solution obtained in step (1), and stir until dissolved.

[0010] (3) The solution obtained in step (2) is transferred to a reaction kettle and placed in a constant temperature drying oven at 160-180° C. for reaction for 20-24 hours.

[0011] (4) washing with alcohol, centrifuging, drying, and finally heat treating in an air atmosphere to obtain a vanadium trioxide / carbon hollow nanosphere material.

[0012] Compared with the existing methods, the present invention has the following technical advantages.

[0013] (1) The raw materials are cheap and the preparation process is simple.

[0014] (2) V 2 O 3 The C / C hollow nanospheres not only have a wide voltage window of -1.1~1.3 V (vs. Ag / AgCl), but also have a specific capacitance of 708.6 F g -1 .

[0015] (3) V 2 O 3 / C hollow nanospheres as electrodes, Na 2 SO 4 The aqueous solution is used as the electrolyte, and the prepared symmetric supercapacitor has an operating voltage of up to 2.4 V and an ultra-high energy density of 96.8 W h kg -1 And excellent cycle stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 V in step (4) of Example 2 2 O 3X-ray diffraction pattern of / C hollow nanospheres.

[0017] Figure 2 V in step (4) of Example 2 2 O 3 / C hollow nanospheres.

[0018] Figure 3 is the V obtained in step (4) of Example 2 2 O 3 / C hollow nanospheres charge and discharge curves.

[0019] Figure 4 is the step (5) in Example 2 with V 2 O 3 / C hollow nanospheres as electrodes to prepare the charge and discharge curves of the aqueous symmetric supercapacitor. DETAILED DESCRIPTION

[0020] In order to make the advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical means involved in each embodiment described in the examples can be diversified and are not limited to the experimental technical means.

[0021] Example 1.

[0022] (1) Weigh 400 mg of glucose and add a mixed solution of 40 mL of deionized water and 10 mL of isopropanol. Stir until dissolved at a stirring rate of 600 rpm.

[0023] (2) Weigh 40 mg of vanadyl acetylacetonate and add it to the glucose solution obtained in step (1), stirring until dissolved at a stirring rate of 600 rpm.

[0024] (3) The solution obtained in step (2) was transferred to a 100 mL reactor and placed in a constant temperature drying oven at 170 °C for 24 hours.

[0025] (4) Wash with alcohol, centrifuge three times, dry under vacuum for 12 h, and finally heat treat in air atmosphere to obtain V 2 O 3 / C hollow nanosphere material. The centrifugal speed is 5000 rpm, the drying temperature is 60 ℃, the drying time is 12 h, the heat treatment temperature is 500 ℃, the heat treatment time is 1.5 h, and the heating rate is 2 ℃ / min.

[0026] (5) With 1 M Na 2 SO 4As electrolyte, the V obtained in step (4) 2 O 3 / C hollow nanosphere electrodes were used as electrodes and cellulose acetate membranes were used as separators to assemble into symmetrical button-type supercapacitors.

[0027] Example 2.

[0028] (1) Weigh 500 mg of glucose and add a mixed solution of 40 mL of deionized water and 10 mL of isopropanol. Stir until dissolved at a stirring rate of 600 rpm.

[0029] (2) Weigh 50 mg of vanadyl acetylacetonate and add it to the glucose solution obtained in step (1), stirring until dissolved at a stirring rate of 600 rpm.

[0030] (3) The solution obtained in step (2) was transferred to a 100 mL reactor and placed in a constant temperature drying oven at 160 °C for 20 hours.

[0031] (4) Wash with alcohol, centrifuge three times, dry under vacuum conditions for 12 hours, and finally heat treat in air atmosphere to obtain V 2 O 3 / C hollow nanosphere material. The centrifugal speed is 5000 rpm, the drying temperature is 60 ℃, the drying time is 12 h, the heat treatment temperature is 500 ℃, the heat treatment time is 1.5 h, and the heating rate is 2 ℃ / min.

[0032] (5) With 1 M Na 2 SO 4 As electrolyte, the V obtained in step (4) 2 O 3 / C hollow nanosphere electrodes were used as electrodes and cellulose acetate membranes were used as separators to assemble into symmetrical button-type supercapacitors.

[0033] Example 3.

[0034] (1) Weigh 600 mg of glucose and add a mixed solution of 40 mL of deionized water and 10 mL of isopropanol. Stir until dissolved at a stirring rate of 600 rpm.

[0035] (2) Weigh 60 mg of vanadyl acetylacetonate and add it to the glucose solution obtained in step (1), stirring until dissolved at a stirring rate of 600 rpm.

[0036] (3) The solution obtained in step (2) was transferred to a 100 mL reactor and placed in a constant temperature drying oven at 180 °C for 24 hours.

[0037] (4) Wash with alcohol, centrifuge three times, dry under vacuum for 12 h, and finally heat treat in air atmosphere to obtain V 2 O 3 / C hollow nanosphere material. The centrifugal speed is 5000 rpm, the drying temperature is 60 ℃, the drying time is 12 h, the heat treatment temperature is 500 ℃, the heat treatment time is 1.5 h, and the heating rate is 2 ℃ / min.

[0038] (5) With 1 M Na 2 SO 4 As electrolyte, the V obtained in step (4) 2 O 3 / C hollow nanosphere electrodes were used as electrodes and cellulose acetate membranes were used as separators to assemble into symmetrical button-type supercapacitors.

[0039] The method of the present invention is easy and controllable, and a V having a high voltage window and a high capacitance is prepared by design. 2 O 3 / C hollow nanosphere electrodes to improve the voltage window and energy density of supercapacitors, which provides certain guiding significance for further promoting the development of aqueous supercapacitors.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, improvement and replacement made within the design concept and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing vanadium trioxide / carbon supercapacitor electrode material, characterized in that The steps include: (1) Add glucose to a mixed solution of deionized water and isopropanol in a volume ratio of 4:1 at a ratio of 40-60 / 5 (g / L), and stir until dissolved; (2) Weighing vanadyl acetylacetonate in a mass ratio of vanadyl acetylacetonate to glucose of 1:8-10, adding the vanadyl acetylacetonate to the glucose solution obtained in step (1), and stirring until dissolved; (3) The solution obtained in step (2) was transferred to a reaction kettle and placed in a constant temperature drying oven at 160-180° C. for reaction for 20-24 hours; (4) washing with alcohol, centrifuging, drying, and finally heat treating in an air atmosphere to obtain a vanadium trioxide / carbon hollow nanosphere material.

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