Construction method of novel Zn-H2O2 battery for producing H2O2

Abstract

The invention relates to a construction method of a novel Zn-H2O2 battery for producing H2O2, and belongs to the technical field of batteries. The construction method comprises the following steps: selenizing ZnO through a hydrothermal method to obtain a ZnSe / ZnO heterojunction electrocatalyst, dispensing the ZnSe / ZnO heterojunction electrocatalyst on a carbon felt (CF) to obtain ZnSe / ZnO / CF as a cathode, taking a Zn sheet as an anode, and in an H-type electrolytic tank with a proton exchange membrane, taking an O2 saturated KOH solution as a cathode chamber electrolyte and a KOH and Zn (Ac) 2 mixed solution as an anode chamber electrolyte. The open-circuit potential of the constructed aqueous Zn-H2O2 battery is stabilized at 1.51 V, the peak power density is 12.0 mW cm <-2 >, the specific energy density is 2938.2 Ws kg <-1 >, an LED lamp can be turned on while H2O2 is synthesized through electro-catalysis, and good charge-discharge cycle stability is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries, and in particular relates to a novel Zn-H2O2 battery construction method for producing H2O2. Background Art

[0002] Ideal metal-air batteries have attracted much attention due to their large battery capacity, low price, light weight, and small size, as well as their huge development potential. Among them, zinc-air batteries have a fairly high theoretical energy density while ensuring a smooth charge and discharge cycle. In alkaline electrolytes, there is a large hydrogen evolution overpotential on the zinc surface, which is conducive to the formation of metallic zinc during the charging process. Zinc oxide, as a discharge product, can be regenerated by electrolysis. Aqueous zinc-air batteries have attracted more and more attention from researchers due to their high energy density, battery voltage, inherent safety, and suitable reduction potential, and are considered to be one of the most technically and economically feasible options for future electric vehicle applications. However, achieving stable operation of long-cycle batteries is the main obstacle to the commercial application of rechargeable zinc-air batteries. To achieve stable operation of rechargeable zinc-air batteries, fundamental challenges such as high polarization and rapid degradation of the air cathode, and low interfacial compatibility and stability of the electrolyte must be addressed. The electrode redox electrocatalytic process during battery charging and discharging is relatively complex, the reaction kinetics are slow, and the electrode polarization is severe, which affects the cycle life of the battery. Therefore, it is necessary to develop high-performance oxygen reduction / evolution reaction (ORR / OER) and catalysts to increase the reaction rate, slow down electrode polarization and extend the battery cycle life.

[0003] When zinc-air batteries are discharged and charged, the air electrode undergoes ORR and OER reactions, respectively. However, ORR and OER involve the transfer of four electrons and four protons, which are slow in kinetics and often require a high overpotential (1.23V vs. RHE), which restricts the charge and discharge performance of zinc-air batteries. Conventional zinc-air batteries often directly adsorb oxygen from the air to participate in the reaction, which is limited by the thermodynamically unfavorable and kinetically slow redox reaction between the positive electrode active material and oxygen, and the use of zinc-air batteries in an oxygen-free environment is greatly limited. In contrast, the two-electron oxygen reduction reaction only requires a potential of 0.7V vs. RHE to achieve the synthesis of H2O2 (O2+2H++2e-→H2O2 E0=0.70V), and the reaction is prone to two-electron ORR to generate H2O2; at the same time, the spontaneous decomposition of H2O2 (H2O2→H2O+1 / 2O2⊿H=-98kJ / mol) can provide timely and uninterrupted energy supply, and the generated O2 can promote the cycle of the cathode reaction. In addition, the generated H2O2, as one of the important chemical raw materials, can be widely used in the fields of chemical industry, medicine, environmental protection, etc., to achieve electrical energy output while synthesizing high value-added chemicals. Summary of the invention

[0004] The object of the present invention is to provide a method for constructing a novel aqueous Zn-H2O2 battery for producing H2O2.

[0005] The technical solution adopted by the present invention is:

[0006] A novel Zn-H2O2 battery construction method for producing H2O2 is as follows: a proton exchange membrane N117 is used as a diaphragm in an H-type electrolyzer, ZnSe / ZnO / CF is used as a cathode, a Zn sheet is used as an anode, the cathode chamber electrolyte is an O2-saturated KOH solution, and the anode chamber electrolyte is a mixed solution of KOH and Zn(Ac)2 to construct a Zn-H2O2 battery.

[0007] Furthermore, in the above-mentioned novel Zn-H2O2 battery construction method for producing H2O2, the cathode chamber electrolyte is an O2-saturated 1M KOH solution.

[0008] Furthermore, in the above-mentioned novel Zn-H2O2 battery construction method for producing H2O2, the anode chamber electrolyte is a mixed solution of 6M KOH and 0.2M Zn(Ac)2.

[0009] Furthermore, in the above-mentioned novel Zn-H2O2 battery construction method for producing H2O2, the preparation method of the ZnSe / ZnO / CF cathode comprises the following steps:

[0010] 1) Weigh 0.297g Zn(NO3)2·6H2O and 6g CO(NH2)2 and dissolve them in 80mL water, stir until completely dissolved, transfer the mixed solution to a Teflon-lined autoclave for thermal reaction, cool to room temperature, wash with water and ethanol several times, and dry in a vacuum drying oven at 60°C; then place the obtained solid in a quartz boat, transfer to a muffle furnace for calcination, and obtain ZnO after natural cooling;

[0011] 2) Weigh 0.02 g NaBH4 and 0.015 g Se powder and disperse them in 50 mL ethanol-water solution, then add 0.8 g ZnO and continue stirring for 30 min, transfer the mixed solution to a Teflon-based autoclave for thermal reaction, cool to room temperature, wash with water and ethanol, and dry in a constant temperature drying oven at 60 ° C to obtain a ZnSe / ZnO heterojunction electrocatalyst;

[0012] 3) Weigh 1 mg of ZnSe / ZnO heterojunction electrocatalyst and disperse it in 500 μL of water containing 5 μL of 5% Nafion solution, and ultrasonically disperse it to form a uniform dispersion; drop the dispersion onto the pretreated carbon felt CF, and dry it at room temperature to obtain a ZnSe / ZnO / CF cathode.

[0013] Furthermore, in the above-mentioned method for preparing the ZnSe / ZnO / CF cathode, in step 1), the thermal reaction conditions in the high-pressure reactor are: 100° C. for 8 hours.

[0014] Furthermore, in the above-mentioned method for preparing the ZnSe / ZnO / CF cathode, in step 1), the calcination conditions in the muffle furnace are: 500° C. for 6 hours.

[0015] Furthermore, in the above-mentioned method for preparing the ZnSe / ZnO / CF cathode, in step 2), the volume ratio of ethanol to water in the ethanol aqueous solution is 1:1.

[0016] Furthermore, in the above-mentioned method for preparing the ZnSe / ZnO / CF cathode, in step 2), the thermal reaction conditions in the high-pressure reactor are: 200° C. for 15 hours.

[0017] Furthermore, in the above method for preparing the ZnSe / ZnO / CF cathode, in step 3), the size of the carbon felt CF is 2 cm×2 cm×0.2 cm.

[0018] The beneficial effects of the present invention are:

[0019] 1. The present invention constructs a novel aqueous Zn-H2O2 battery, using a three-dimensional flower-shaped ZnSe / ZnO heterojunction electrocatalyst as a cathode to achieve a low-potential cathode reaction to drive the battery to a long-term charge and discharge cycle; at the same time, high value-added chemical H2O2 is obtained, promoting self-charging zinc-based batteries to achieve ultrafast power generation and energy storage, which can be applied to the electrocatalytic preparation of H2O2 and batteries and other related fields.

[0020] 2. The open circuit potential of the aqueous Zn-H2O2 battery constructed by the method of the present invention is stable at 1.51 V, and the peak power density is 12.0 mW cm -2 , the specific energy density is 2938.2Ws kg -1 It can realize the electrocatalytic synthesis of H2O2 and light up the LED lamp at the same time, and has good charge and discharge cycle stability, providing technical support for the development and application of self-charging zinc-based batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 (a) is the scanning electron microscope (SEM) image and (b) X-ray diffraction (XRD) spectrum of ZnSe / ZnO.

[0022] Figure 2 The open circuit potential curve of Zn-H2O2 battery and the actual battery voltage (a), current density and power density curve (b) and specific energy density curve (c).

[0023] Figure 3It is the charge and discharge curve of Zn-H2O2 battery at different current densities.

[0024] Figure 4 This is the long-term charge and discharge cycle curve of Zn-H2O2 battery.

[0025] Figure 5 (a) is the H2O2 production diagram of Zn-H2O2 battery catalytic synthesis at different current densities and the H2O2 production diagram during long-term charging and discharging. DETAILED DESCRIPTION

[0026] Example 1 Preparation of flower-shaped ZnSe / ZnO / CF cathode

[0027] (I) Preparation of ZnO

[0028] Weigh 0.297g Zn(NO3)2·6H2O and 6g CO(NH2)2 and dissolve them in 80mL water, stir until completely dissolved, transfer the mixed solution to a 100mL Teflon-lined autoclave, react at 100℃ for 8h, cool to room temperature, wash with water and ethanol several times, and dry in a vacuum oven at 60℃. Then place the obtained solid in a quartz boat, transfer to a muffle furnace, heat to 500℃ in an air atmosphere and keep for 6h, and obtain ZnO after natural cooling.

[0029] (II) Preparation of ZnSe / ZnO

[0030] 0.02 g NaBH4 and 0.015 g Se powder were weighed and dispersed in 50 mL ethanol aqueous solution (the volume ratio of ethanol to water was 1:1), and then 0.8 g ZnO precursor was added and stirred for 30 min. The mixed solution was transferred to a 100 mL Teflon-lined high-pressure reactor and reacted at 200 °C for 15 h. After cooling to room temperature, it was washed with water and ethanol several times and dried at 60 °C in a constant temperature drying oven to obtain a ZnSe / ZnO heterojunction electrocatalyst.

[0031] (III) Preparation of ZnSe / ZnO / CF cathode

[0032] 1 mg of ZnSe / ZnO heterojunction electrocatalyst was weighed and dispersed in 500 μL of water containing 5 μL of 5% Nafion solution, and ultrasonically dispersed to form a uniform dispersion. The dispersion was drop-coated on pretreated carbon felt (CF, 2 cm×2 cm×0.2 cm) and dried at room temperature to obtain a ZnSe / ZnO / CF cathode.

[0033] Figure 1 a is the SEM image of ZnSe / ZnO. Figure 1As can be seen in a, ZnSe / ZnO is a three-dimensional flower-like structure formed by self-assembly of a large number of nanoparticles with a size of about 3-10 μm, which is beneficial to improving the catalytic active sites. Figure 1 b is the XRD spectrum of ZnSe / ZnO. Figure 1 As can be seen in b, the ZnSe / ZnO heterogeneous crystalline structure has the characteristic diffraction peaks of hexagonal wurtzite ZnO (JCPDS NO.36-1451) and ZnSe (JCPDS NO.37-1463), confirming the successful synthesis of the ZnSe / ZnO heterojunction.

[0034] Example 2 Zn-H2O2 battery construction

[0035] In the H-type electrolyzer, a proton exchange membrane (N117) was used as a diaphragm, ZnSe / ZnO / CF was used as a cathode, a Zn sheet was used as an anode, the cathode electrolyte was 20 mL of a 1 M KOH solution saturated with O2, and the anode electrolyte was a mixed solution of 6 M KOH and 0.2 M Zn (Ac) 2 to construct a Zn-H2O2 battery. During the electrically driven catalytic reaction, 0.5 mL of the cathode electrolyte solution was taken out every 30 minutes, and the H2O2 production was detected by potassium titanium oxalate colorimetry.

[0036] The results are as follows Figure 2 As shown in a, the open circuit voltage of the Zn-H2O2 battery is 1.51V, which is consistent with the result measured by an external multimeter; Figure 2 As shown in b, the peak power density of the Zn-H2O2 battery is 12.0 mW cm -2 ;from Figure 2 c shows that the specific energy density of Zn-H2O2 battery is 2938.2Ws kg -1 .

[0037] from Figure 3 It can be seen that the Zn-H2O2 battery can still maintain a stable charge and discharge voltage under different current densities.

[0038] Maintaining a constant current density (5 mA cm -2 ), a charge-discharge cycle was performed every 40 minutes, and the charge-discharge experiment was carried out for 100 hours. Figure 4 As shown, the Zn-H2O2 battery has an energy efficiency of 63.4% and can maintain a long and stable charge and discharge cycle.

[0039] like Figure 5 As shown in a, with the increase of current density, the H2O2 production also increases. The current density is maintained at 5 mA cm -2 After 1 h of electrocatalysis, the yield of H2O2 was 7.0 M g cat -1 .from Figure 5 b It can be seen that the current density is maintained at 5 mA cm -2 Constant cyclic charging and discharging can simultaneously realize electrocatalytic synthesis of H2O2.

Claims

1. A novel Zn-H2O2 battery construction method for producing H2O2, characterized in that: The method is as follows: in an H-type electrolyzer, a proton exchange membrane N117 is used as a diaphragm, ZnSe / ZnO / CF is used as a cathode, a Zn sheet is used as an anode, the cathode chamber electrolyte is an O2-saturated KOH solution, and the anode chamber electrolyte is a mixed solution of KOH and Zn(Ac)2 to construct a Zn-H2O2 battery.

2. A novel Zn-H2O2 battery construction method for producing H2O2 according to claim 1, characterized in that: The cathode chamber electrolyte is an O2-saturated 1M KOH solution.

3. A novel Zn-H2O2 battery construction method for producing H2O2 according to claim 1, characterized in that: The electrolyte in the anode chamber is a mixed solution of 6M KOH and 0.2M Zn(Ac)2.

4. A novel Zn-H2O2 battery construction method for producing H2O2 according to claim 1, characterized in that: The preparation method of the ZnSe / ZnO / CF cathode comprises the following steps: 1) Weigh 0.297g Zn(NO3)2·6H2O and 6g CO(NH2)2 and dissolve them in 80mL water, stir until completely dissolved, transfer the mixed solution to a Teflon-lined autoclave for thermal reaction, cool to room temperature, wash with water and ethanol several times, and dry in a vacuum drying oven at 60°C; then place the obtained solid in a quartz boat, transfer to a muffle furnace for calcination, and obtain ZnO after natural cooling; 2) Weigh 0.02 g NaBH4 and 0.015 g Se powder and disperse them in 50 mL ethanol-water solution, then add 0.8 g ZnO and continue stirring for 30 min, transfer the mixed solution to a Teflon-based autoclave for thermal reaction, cool to room temperature, wash with water and ethanol, and dry in a constant temperature drying oven at 60 ° C to obtain a ZnSe / ZnO heterojunction electrocatalyst; 3) Weigh 1 mg of ZnSe / ZnO heterojunction electrocatalyst and disperse it in 500 μL of water containing 5 μL of 5% Nafion solution, and ultrasonically disperse it to form a uniform dispersion; drop the dispersion onto the pretreated carbon felt CF and dry it at room temperature to obtain a ZnSe / ZnO / CF cathode.

5. A novel Zn-H2O2 battery construction method for producing H2O2 according to claim 4, characterized in that: In step 1), the thermal reaction conditions in the high-pressure reactor are: 100° C. for 8 h.

6. A novel Zn-H2O2 battery construction method for producing H2O2 according to claim 4, characterized in that: In step 1), the calcination condition in the muffle furnace is: 500° C. for 6 hours.

7. A novel Zn-H2O2 battery construction method for producing H2O2 according to claim 4, characterized in that: In step 2), the volume ratio of ethanol to water in the ethanol aqueous solution is 1:

1.

8. A novel Zn-H2O2 battery construction method for producing H2O2 according to claim 4, characterized in that: In step 2), the thermal reaction conditions in the high-pressure reactor are: 200° C. for 15 h.

9. A novel Zn-H2O2 battery construction method for producing H2O2 according to claim 4, characterized in that: In step 3), the size of the carbon felt CF is 2 cm×2 cm×0.2 cm.

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