Antimony negative electrode and aqueous alkaline battery based on antimony negative electrode

Abstract

The present invention belongs to the field of electrochemical energy storage, and specifically relates to an antimony negative electrode and an aqueous alkaline battery based on the antimony negative electrode. The present invention discloses an antimony negative electrode, comprising a substrate and antimony metal deposited on the substrate; a solution of alkali and antimony source is used as an electrolyte to electro-deposit the antimony metal on the substrate. The antimony negative electrode prepared by the present invention has the characteristics of low electrode potential, high specific capacity, excellent rate performance, good cycle stability, low cost and environmental friendliness. The aqueous alkaline battery based on the antimony negative electrode of the present invention has high energy density and long cycle life.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical energy storage, and more specifically, relates to an antimony negative electrode and an aqueous alkaline battery based on the antimony negative electrode. Background Art

[0002] Aqueous alkaline batteries, which use alkaline aqueous solutions as electrolytes, are an important type of electrochemical power source system with the advantages of high energy density, high power density, low cost, high safety, simple preparation process, and clean and pollution-free. They have been applied in small electrical appliances, portable electronic products, electric vehicles, and grid energy storage. At present, most research focuses on positive electrode materials and has made practical progress. However, the performance of the negative electrode materials currently developed lags far behind that of the positive electrode, which seriously restricts the application and development of aqueous alkaline batteries. For example, the nickel-zinc, nickel-iron, and nickel-cadmium batteries that are widely reported at present all face problems such as low energy density and poor cycle life, and cannot meet the needs of future portable, lightweight, and micro devices.

[0003] The development of aqueous alkaline batteries has a long history, but the lag of negative electrode materials has seriously affected the development of the system in practical applications and is also the main challenge facing the development of the system. According to the energy storage mechanism, the negative electrode materials in aqueous alkaline batteries can be divided into two categories, one is the conversion negative electrode and the other is the deposition / dissolution negative electrode. The former mainly stores energy through the redox reaction that occurs during the charge and discharge process, such as bismuth, cadmium, iron oxide and other materials. The latter usually stores and releases energy through the deposition / dissolution process of metals on the electrode surface. Compared with the conversion negative electrode, the deposition / dissolution negative electrode (such as zinc negative electrode) has faster reaction kinetics and higher charge transfer capacity. However, the deposition / dissolution negative electrode faces serious dendrite problems as well as surface passivation / corrosion and hydrogen evolution side reactions. As a result, it leads to low energy density and stability. Therefore, the development of new deposition / dissolution negative electrode materials has injected new vitality into the development of aqueous alkaline batteries. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention provides an antimony negative electrode, which has the characteristics of low electrode potential, high specific capacity, excellent rate performance, good cycle stability, low cost and environmental friendliness.

[0005] The present invention also provides a method for preparing the antimony negative electrode.

[0006] The present invention also provides an application of the antimony negative electrode in an alkaline battery.

[0007] The present invention also provides an alkaline battery having the antimony negative electrode.

[0008] According to one aspect of the present invention, an antimony negative electrode is provided, comprising a substrate and antimony metal deposited on the substrate; a mixed solution of alkali and antimony source is used as an electrolyte to electrodeposit the antimony metal on the substrate.

[0009] In some embodiments of the present invention, the substrate is a carbon material or a metal, that is, the carbon material or the metal is used as the negative electrode current collector.

[0010] In some preferred embodiments of the present invention, the carbon material includes but is not limited to one or more of carbon fiber, porous carbon, carbon nanotube and acetylene black. Among them, the conductivity, wettability, specific surface area and chemical adsorption performance of the carbon material are the main factors affecting the performance of the antimony negative electrode. The high-quality carbon material substrate is conducive to the reversible deposition / dissolution of antimony metal on its surface, which is conducive to obtaining a high specific energy and long-life aqueous alkaline battery. The carbon material selection is rich in variety and low in cost, which can meet the demand for low-cost power sources.

[0011] In some preferred embodiments of the present invention, the metal includes but is not limited to one or more of nickel, titanium, copper, lead, tin, bismuth, tin-antimony alloy, lead-antimony alloy and copper-antimony alloy. The metal substrate has good electrical conductivity and antimony affinity, so the metal substrate can improve the deposition and dissolution process of the antimony negative electrode, thereby improving the coulombic efficiency and discharge depth of the antimony negative electrode and increasing the specific capacity of the antimony negative electrode.

[0012] In some embodiments of the present invention, the electrolyte is an aqueous solution, that is, the electrolyte is a mixed aqueous solution of an alkali and an antimony source.

[0013] In some embodiments of the present invention, the base includes, but is not limited to, one or more of potassium hydroxide, sodium hydroxide and lithium hydroxide.

[0014] In some preferred embodiments of the present invention, the concentration of the alkali in the mixed solution is 1-12 mol / L; for example, it can be 1 mol / L, 2 mol / L, 4 mol / L, 6 mol / L, 8 mol / L, 10 mol / L or 12 mol / L. Since the source of the alkali is abundant and the price is low, the application cost of the antimony negative electrode is reduced; by regulating the concentration of the alkali, the ionic conductivity of the electrolyte can be improved, thereby regulating the charge and discharge reversibility and cycle stability of the antimony negative electrode.

[0015] In some embodiments of the present invention, the antimony source is a trivalent antimony source, specifically, a trivalent antimony salt. More specifically, the antimony source includes, but is not limited to, one or more of antimony acetate, antimony sulfate, antimony trichloride, and potassium antimony tartrate. The trivalent antimony source is dissolved in an alkaline electrolyte, wherein antimony is in the form of SbO2 -In the charging process, it will be deposited on the substrate to form Sb metal. Different antimony sources have different coordination forms in the alkaline solution. Affected by different anions, they will show different states during the desolvation process and surface adsorption, nucleation, and growth process.

[0016] In some preferred embodiments of the present invention, the concentration of the antimony source in the mixed solution is 0.1-3 mol / L; for example, it can be 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L or 3 mol / L. By regulating the concentration of the antimony source, the deposition / solvent rate of the antimony metal on the surface can be regulated, thereby regulating the rate performance of the antimony negative electrode.

[0017] In some embodiments of the present invention, the deposition amount of antimony metal is 0.5-10 mAh cm -2 , for example, 0.5 mAh cm -2 , 2mAh cm -2 、5mAh cm -2 、7mAh cm -2 or 10mAh cm -2 .

[0018] In some embodiments of the present invention, the electrolyte further comprises an additive.

[0019] In some preferred embodiments of the present invention, the concentration of the additive is below 3 mol / L, for example, it can be 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L or 3 mol / L.

[0020] In some embodiments of the invention, the additive includes a large cationic salt and / or an anionic surfactant.

[0021] In some specific embodiments of the present invention, large cation salts include but are not limited to one or more of Li, Na, Al and Rb salts. In some specific embodiments of the present invention, anionic surfactants include but are not limited to one or more of fatty acid salts, sulfonates, sulfate esters and phosphate esters, such as sodium dodecyl sulfonate, hexadecyl trimethyl ammonium bromide (CTAB) and / or sodium dodecyl sulfate, etc.

[0022] The addition of large-sized cations to the electrolyte is beneficial to regulating the transfer rate of water molecules in the electrolyte, thereby regulating the deposition of antimony metal on the electrode surface. The addition of anionic surfactants is beneficial to changing the SbO2 - The coordination environment of ions reduces SbO2 - The diffusion of ions on the electrode surface inhibits side reactions and regulates the deposition morphology.

[0023] According to another aspect of the present invention, a method for preparing the above antimony negative electrode is provided, wherein a mixed solution of alkali and antimony source is used as an electrolyte to obtain the antimony negative electrode by electrodeposition.

[0024] According to another aspect of the present invention, a use of the antimony negative electrode in an alkaline battery is proposed.

[0025] According to another aspect of the present invention, an alkaline battery is provided, comprising the antimony negative electrode. Preferably, the alkaline battery is an aqueous alkaline battery.

[0026] The aqueous alkaline battery based on antimony negative electrode proposed by the present invention focuses on using antimony element as the active material of the negative electrode.

[0027] The present invention uses antimony as the main negative electrode active material of the aqueous alkaline battery, and its working principle and characteristics are as follows:

[0028] 1) In alkaline electrolyte, metal Sb and SbO2 - The redox electrode potential between them can reach about -0.66 V vs. SHE, and as the negative electrode it has a lower electrode potential.

[0029] 2) Antimony negative electrode has 660mAh g -1 It has a high theoretical specific capacity and low cost, about 7$ / kg.

[0030] 3) In alkaline solution, antimony exists in the form of SbO2 - , Sb and SbO2 - Energy can be stored and released through the electrochemical reaction mechanism of deposition / dissolution, with excellent electrochemical kinetics, which is conducive to the high rate performance of the battery.

[0031] It can be seen that aqueous alkaline batteries based on antimony negative electrode have the characteristics of high specific capacity, high rate performance, and long life.

[0032] The present invention has the following beneficial effects:

[0033] The present invention uses a solution of alkali and antimony source as an electrolyte to prepare an antimony negative electrode by an electrodeposition method. In an alkaline solution, antimony exists in the form of SbO2 - , Sb and SbO2 - Energy can be stored and released through the electrochemical reaction mechanism of deposition / dissolution. The antimony negative electrode prepared by the present invention has the characteristics of low electrode potential, high specific capacity, excellent rate performance, good cycle stability, low cost and environmental friendliness. The aqueous alkaline battery based on the antimony negative electrode of the present invention has high energy density and long cycle life. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0035] Figure 1 Scanning electron microscope (SEM) images of carbon fiber (CC) and carbon nanotube network (CC-CNT) at different magnifications. (a, b) CC; (c, d) CC-CNT.

[0036] Figure 2 Performance diagram of Sb / CC and Sb / CC-CNT negative electrodes. (a) Cyclic voltammetry curve of Sb / CC negative electrode; (b) Cyclic voltammetry curve of Sb / CC-CNT negative electrode; (c) Cyclic voltammetry curve of Sb / CC and Sb / CC-CNT negative electrodes at the same current density (2 mA cm -2 ), deposition / dissolution electrical curves at different capacities.

[0037] Figure 3 SEM images of antimony metal deposited on the brass surface at different magnifications.

[0038] Figure 4 Charge-discharge curves and Coulomb efficiency diagram of brass-based antimony anode (2 mA cm -2 , 2mAh cm -2 ).

[0039] Figure 5 Effects of different concentrations of alkali on the charge-discharge performance of antimony anode (5 mA cm -2 , 0.5mAh cm -2 ).

[0040] Figure 6 Effects of different concentrations of potassium antimony tartrate on the performance of antimony negative electrode; (a) Cyclic voltammetry curve (10mVs -1 ); (b) charge-discharge curve (5 mA cm -2 ,0.5mAh cm -2 ).

[0041] Figure 7 Effects of different additives on the charge and discharge performance of antimony anode (5 mA cm -2 , 0.5mAh cm -2 ).

[0042] Figure 8 Performance diagram of Fe-Co(OH)2 / / Sb alkaline battery based on CS and D-CS; including: (a) charge and discharge curve; (b) rate performance; (c) cycle stability. DETAILED DESCRIPTION

[0043] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0044] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art. Unless otherwise specified, the reagents and materials used in the present invention are commercially available. In this section, the concentration is expressed in M ​​(mol / L).

[0045] Example 1

[0046] Carbon fiber (CC) and carbon nanotube network in situ grown on carbon fiber (CC-CNT) were used as substrates, respectively. A mixed solution of 3 M KOH and 0.1 M potassium antimony tartrate was used as the electrolyte. A graphite rod was used as the counter electrode, and a Hg / HgO electrode was used as the reference electrode. The deposition capacity of Sb metal was fixed, and the deposition / dissolution performance of Sb metal on the surfaces of different samples was compared.

[0047] Figure 1 The SEM images of CC and CC-CNT show that the carbon fiber has a smooth surface and a small specific surface area, while the carbon nanotube network is densely distributed on the carbon fiber to form a conductive network with a large specific surface area and uniform pores in the gaps, which is conducive to the storage and reaction of the electrolyte.

[0048] like Figure 2 As shown in Figure 2, the cyclic voltammetry (CV) curves of the Sb / CC and Sb / CC-CNT anodes both exhibit a pair of symmetrical redox peaks, corresponding to the deposition and dissolution of Sb metal. It can be seen that the Sb / CC-CNT anode has a larger current density and a smaller polarization, indicating that the Sb / CC-CNT anode has better conductivity and more reversible Sb metal deposition / dissolution. In addition, at 2 mA cm -2 Under current density, the CP curves of different capacities show that compared with the Sb / CC anode, the Sb / CC-CNT anode exhibits excellent charge and discharge performance, with higher coulombic efficiency, stronger inhibition of hydrogen evolution, and longer cycle life.

[0049] Example 2

[0050] Using brass as the substrate, a mixed solution of 3M KOH and 0.1M potassium antimony tartrate as the electrolyte, a graphite rod as the counter electrode, and a Hg / HgO electrode as the reference electrode, constant current deposition / dissolution of Sb metal was used to test the cyclic stability of the antimony negative electrode.

[0051] Figure 3This is a SEM image of antimony metal deposited on the brass surface. It can be seen that antimony metal can be evenly deposited on the brass surface, the brass substrate is completely covered, and the deposited antimony metal particles are uniform in size without obvious protrusions or shedding. This shows that the brass substrate has a good interaction with the antimony metal and is an excellent antimony negative electrode substrate material.

[0052] Figure 4 The charge-discharge curve and coulomb efficiency diagram of the brass-based antimony negative electrode at 2 mA cm -2 The current density is 2 mAh cm-2 for Sb deposition. -2 Under the conditions of high temperature and low charge, the antimony anode can be stably cycled for 500 cycles, and its Coulombic efficiency can be maintained above 80% at 400 cycles, indicating that the brass substrate has good reversible deposition / dissolution properties of antimony metal.

[0053] Example 3

[0054] With carbon fiber as substrate, a mixed solution of KOH and 0.1M potassium antimony tartrate with different concentrations (1M, 2M, 3M, 4M and 6M) as electrolyte, a graphite rod as counter electrode, and a Hg / HgO electrode as reference electrode, the charge and discharge performance of the antimony negative electrode was tested. The charge and discharge current density of the electrode was 5mA cm -2 , the deposition amount of antimony metal is 0.5 mAh cm -2 .

[0055] from Figure 5 It can be seen that the concentration of KOH has a great influence on the charge and discharge performance of the antimony negative electrode. When the concentration of KOH is 6M, the antimony negative electrode has the smallest charging platform, while when the concentration is 4M, the antimony negative electrode has the highest coulombic efficiency and the smallest polarization.

[0056] Example 4

[0057] With carbon fiber as substrate, 3M KOH and different concentrations (0.5M, 1M, 1.5M, 2M, 2.5M and 3M) of potassium antimony tartrate mixed solution as electrolyte, graphite rod as counter electrode, Hg / HgO electrode as reference electrode, the charge and discharge performance of antimony negative electrode was tested respectively. The charge and discharge current of the electrode was 5mA cm -2 , the deposition amount of antimony metal is 0.5 mAh cm -2 .

[0058] from Figure 6 It can be seen that when different concentrations of potassium antimony tartrate are added, the cyclic voltammetry curve of the antimony negative electrode shows different polarization characteristics, and the concentration of potassium antimony tartrate also has a great influence on the current density. In addition, from the charge and discharge curve of the antimony negative electrode, it can be found that the charge and discharge platform of the antimony negative electrode is greatly affected by the concentration of potassium antimony tartrate.

[0059] Example 5

[0060] With carbon fiber as substrate, a mixed solution of 3M KOH and 0.1M potassium antimony tartrate was used as electrolyte. Different additives (0.1M-1M) were added to modify the electrolyte. Graphite rod was used as counter electrode and Hg / HgO electrode was used as reference electrode to test the charge and discharge performance of antimony negative electrode. The charge and discharge current of the electrode was 5mA cm -2 , the deposition amount of antimony metal is 0.5 mAh cm -2 .

[0061] from Figure 7 It can be seen that adding different surfactants to modify the electrolyte can greatly improve the deposition / dissolution efficiency of the antimony negative electrode, thereby improving the coulombic efficiency of the antimony negative electrode.

[0062] Example 6

[0063] Carbon fiber (CS) and carbon fiber with rich intrinsic carbon defects (D-CS) were used as substrates, a mixed solution of 3M KOH+0.1M potassium antimony tartrate was used as the electrolyte, and Fe-doped Co(OH)2 (Fe-Co(OH)2) was used as the matching positive electrode to assemble Fe-Co(OH)2 / / Sb alkaline batteries.

[0064] from Figure 8 It can be seen that at a current density of 6 mA cm -2 Under the condition of high temperature, the Sb / D-CS electrode showed a high temperature of 0.32 mAh cm -2 The area capacity of the battery is much higher than that of the conventional battery, and it exhibits better rate performance; after 1800 charge and discharge cycles, its area capacity and coulombic efficiency have basically not decayed.

[0065] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. Aqueous alkaline battery antimony negative electrode, characterized in that: The invention comprises a substrate and an antimony metal deposited on the substrate; in an electrolyte of an alkaline battery, the antimony metal and SbO 2- Energy storage and release via electrochemical reaction mechanism of deposition / dissolution; The electrolyte is a mixed solution of alkali and antimony source; The substrate is a carbon material or a metal; the metal is selected from brass; and the carbon material is a carbon nanotube network grown in situ on carbon fibers.

2. The aqueous alkaline battery antimony negative electrode according to claim 1, characterized in that: The alkali is selected from one or more of potassium hydroxide, sodium hydroxide and lithium hydroxide; the antimony source is a trivalent antimony source; the trivalent antimony source is selected from one or more of antimony acetate, antimony sulfate, antimony trichloride and potassium antimony tartrate.

3. The aqueous alkaline battery antimony negative electrode according to claim 1, characterized in that: The concentration of the alkali in the mixed solution is 1-12 mol / L; the concentration of the antimony source in the mixed solution is 0.1-3 mol / L; the deposition amount of the antimony metal is 0.5-10 mAh cm -2 .

4. The aqueous alkaline battery antimony negative electrode according to any one of claims 1 to 3, characterized in that: The electrolyte further includes an additive; the concentration of the additive is below 3 mol / L.

5. The aqueous alkaline battery antimony negative electrode according to claim 4, characterized in that: The additive comprises a large cation salt and / or an anionic surfactant; the large cation salt is selected from one or more of Li, Na, Al and Rb salts.

6. The aqueous alkaline battery antimony negative electrode according to claim 5, characterized in that: The anionic surfactant is selected from one or more of fatty acid salts, sulfonates, sulfate esters and phosphate esters.

7. The method for preparing an antimony negative electrode for an aqueous alkaline battery according to any one of claims 1 to 6, characterized in that: The antimony negative electrode is obtained by electrodeposition using a mixed solution of alkali and antimony source as an electrolyte.

8. Aqueous alkaline battery, characterized in that: The invention comprises an antimony negative electrode for an aqueous alkaline battery as described in any one of claims 1-6.

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